 INTRODUCTION TO GARDENING WITHOUT IRRIGATION OR WITHOUT MUCH ANYWAY This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. Read by Betsy Bush, August 2009. GARDENING WITHOUT IRRIGATION OR WITHOUT MUCH ANYWAY by Steve Solomon. INTRODUCTION. Starting a New Gardening Era First, you should know why Ameritime Northwest Raised Bed Gardener named Steve Solomon became worried about his dependence on irrigation. I'm from Michigan. I moved to Lorraine, Oregon in April 1978 and homesteaded on five acres in what I thought at the time was a cool, showery, green valley of liquid sunshine and rainbows. I intended to put in a big garden and grow as much of my own food as possible. Two months later in June, just as my garden began needing water, my so-called 15-gallon-per-minute well began to falter, yielding less and less with each passing week. By August, it delivered about three gallons per minute. Fortunately, I wasn't faced with a completely dry well or one that had shrunk to below one gallon per minute as I soon discovered many of my neighbors were cursed with. Three gallons per minute won't supply a fan nozzle or even a common impulse sprinkler. But I could still sustain my big raised bed garden by watering all night, five or six nights a week, with a single two-and-a-half gallon-per-minute sprinkler that I moved from place to place. I had repeatedly read that gardening in raised beds was the most productive vegetable-growing method, required the least work, and was the most water-efficient system ever known. So, without adequate irrigation, I would have concluded that food self-sufficiency on my homestead was not possible. In late September of that first year, I could still run that single sprinkler. What a relief not to have invested every last scent in land that couldn't feed us. For many succeeding years at Lorraine, I raised lots of organically grown food on densely planted raised beds. But the realities of being a country gardener continued to remind me of how tenuous my irrigation supply actually was. We country folks have to be self-reliant. I am my own sanitation department. I maintain my own 800-foot-long driveway. The septic system puts me in sewage business. A long, long-response time to my 911 calls means I'm my own self-defense force. And I'm my own water department. Without regular and heavy watering during high summer, dense stands of vegetables become stunted in a matter of days. Pump failure has brought my raised bed garden close to that several times. Before my frantic efforts got the water flowing again, I could feel the stressed-out garden screaming like a hungry baby. As I came to understand our climate, I began to wonder about complete food self-sufficiency. How did the early pioneers irrigate their vegetables? There probably aren't more than a thousand homestead sites in the entire maritime northwest with gravity water. Hand pumping into hand-carried buckets is impractical and extremely tedious. Wind-powered pumps are expensive and have severe limits. The combination of dependably rainless summers, the realities of self-sufficient living, and my homesteads' poor well turned out to be an opportunity. For I continued wondering about gardens and water, and discovered a method for growing a lush, productive vegetable garden on deep soil with little or no irrigation in a climate that reliably provides 8 to 12 virtually dry weeks every summer. Gardening with less irrigation. Being a garden writer, I was on the receiving end of quite a bit of local lore. I had heard of someone growing unirrigated carrots on sandy soil in southern Oregon by sowing early and spacing the roots one foot apart in rows four feet apart. The carrots were reputed to grow to enormous sizes, and the overall yield in pounds per square foot occupied by the crop was not as low as one might think. I read that Native Americans in the southwest grew remarkable desert gardens with little or no water, and that Native South Americans in the highlands of Peru and Bolivia grow food crops in a land with 8 to 12 inches of rainfall. So I had to wonder what our own pioneers did. In 1987 we moved 50 miles south to a much better homestead with more acreage and an abundant well. Ironically, only then did I grow my first summertime vegetable without irrigation. Being a low-key survivalist at heart, I was working at growing my own seeds. The main danger to attaining good germination is in repeatedly moistening developing seeds. So in early March 1988 I moved six winter surviving savory cabbage plants far beyond the irrigated soil of my raised bed vegetable garden. I transplanted them four feet apart because blooming brassicas make huge sprays of flower stocks. I did not plan to water these plants at all, since cabbage seed forms during May and dries down during June as the soil naturally dries out. This is just what happened, except that one plant did something a little unusual, though not unheard of. Instead of completely going into bloom and then dying after setting a massive load of seeds, this plant also threw a vegetative bud that grew a whole new cabbage among the seed stocks. With increasing excitement I watched this head grow steadily larger, through the hottest and driest summer I had ever experienced. Realizing I was witnessing revelation, I gave the plant absolutely no water, though I did hoe out the weeds around it after I cut the seed stocks. I harvested the unexpected lesson at the end of September. The cabbage weighed in at six or seven pounds and was sweet and tender. Up to that time all my gardening had been on thoroughly and uniformly watered raised beds. Now I saw that elbow room might be the key to gardening with little or no irrigating, so I began looking for more information about dry gardening and soil water physics. In spring 1989 I tilled four widely separated, unirrigated experimental rows in which I tested an assortment of vegetable species spaced far apart in the row. Out of curiosity I decided to use absolutely no water at all, not even to sprinkle the seeds to get them germinating. I sowed a bit of kale, savory cabbage, purple sprouting broccoli, carrots, beets, parsnips, parsley, endive, dry beans, potatoes, French sorrel, and a couple of field corn stocks. I also tested one compact bush, determinate, and one sprawling, indeterminate tomato plant. Many of these vegetables grew surprisingly well. I ate unwattered tomatoes July through September. Kale, cabbages, parsley, and root crops fed us during the winter. The purple sprouting broccoli bloomed abundantly the next March. In terms of quality all the harvest was acceptable. The root vegetables were far larger, but only a little bit tougher and quite a bit sweeter than usual. The potatoes yielded less than I'd been used to and had thicker than usual skin, but also had a better flavor and kept well through the winter. The following year I grew two parallel gardens. One, my insurance garden, was thoroughly irrigated, guaranteeing we would have plenty to eat. Another experimental garden of equal size was entirely unirrigated. There I tested larger plots of species that I hoped could grow through a rainless summer. By July growth on some species had slowed to a crawl and they looked a little gnarly, wondering if a hidden cause of what appeared to be moisture stress might actually be nutrient deficiencies. I tried spraying liquid fertilizer directly on these gnarly leaves, a practice called foliar feeding. It helped greatly because, I reasoned, most fertility is located in the top soil, and when it gets dry the plants draw on subsoil moisture, so surface nutrients, though still present in the dry soil, become unobtainable. That being so, I reasoned that some of these species might do even better if they had just a little fertilized water. So I improvised a simple drip system and metered out 4 or 5 gallons of liquid fertilizer to some of the plants in late July and 4 gallons more in August. To some species extra-fertilized water, what I called fertigation, hardly made any difference at all. But unirrigated winter squash vines, which were small and scraggly and yielded at about 15 pounds of food, grew more lushly when given a few 5-gallon fertilizer fortified assists and yielded 50 pounds. 30 pounds of squash for 25 extra gallons of water and a bit of extra nutrition is a pretty good exchange in my book. The next year I integrated all this new information into just one garden. Water-loving species, like lettuce and celery, were grown through the summer on a large, thoroughly irrigated, raised bed. The rest of the garden was given no irrigation at all or minimally metered out vertigations. Some unirrigated crops were foliar fed weekly. Everything worked in 1991 and I found still other species that I could grow surprisingly well on surprisingly small amounts of water, or none at all. So the next year, 1992, I set up a sprinkler system to water the intensive raised bed and used the overspray to support species that grew better with some moisture supplementation. I continued using my improvised drip system to help still others, while keeping a large section of the garden entirely unwatered, and at the end of that summer I wrote this book. What follows is not mere theory, not something I read about or saw others do. These techniques are tested and workable. The next to last chapter of this book contains a complete plan of my 1992 garden with explanations and discussions of the reasoning behind it. In Waterwise Vegetables, I assume that my readers already are growing food, probably on raised beds, already know how to adjust their gardening to this region's climate, and know how to garden with irrigation. If you don't have this background, I suggest you read my other garden book, Growing Vegetables West of the Cascades. Sasquatch Books, 1989. Steve Solomon. End of introduction. Chapter 1 of Gardening Without Irrigation Or Without Much, Anyway. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. Read by Betsy Bush, August 2009. Gardening Without Irrigation, Or Without Much, Anyway. By Steve Solomon. Chapter 1. Predictably Rainless Summars. In the eastern United States, summertime rainfall can support gardens without irrigation, but is just irregular enough to be worrisome. West of the Cascades, we go into the summer growing season certain we must water regularly. My own many times revised book, Growing Vegetables West of the Cascades, correctly emphasized that moisture-stressed vegetables suffer greatly. Because I had not yet noticed how plant spacing affects soil moisture loss, in that book I stated a half-truth as law. Soil moisture loss averages one and a half inches per week during summer. This figure is generally true for raised bed gardens west of the Cascades, so I recommended adding one and a half inches of water each week and even more during really hot weather. Summertime Rainfall West of the Cascades, in Inches. Location, Eureka, California. April, 3.0. May, 2.1. June, 0.7. July, 0.1. August, 0.3. September, 0.7. October, 3.2. Medford, Oregon. April, 1.0. May, 1.4. June, 0.98. July, 0.3. August, 0.3. September, 0.6. October, 2.1. Eugene, Oregon. April, 2.3. May, 2.1. June, 1.3. July, 0.3. August, 0.6. September, 1.3. October, 4.0. Portland, Oregon. April, 2.2. May, 2.1. June, 1.6. July, 0.5. August, 0.8. September, 1.6. October, 3.6. Astoria, Oregon. April, 4.6. May, 2.7. June, 2.5. July, 1.0. August, 1.5. September, 2.8. October, 6.8. Olympia, Washington. April, 3.1. May, 1.9. June, 1.6. July, 0.7. August, 1.2. September, 2.1. October, 5.3. Seattle, Washington. April, 2.4. May, 1.7. June, 1.6. July, 0.8. August, 1.0. September, 2.1. October, 4.0. Bellingham, Washington. April, 2.3. May, 1.8. June, 1.9. July, 1.0. August, 1.1. September, 2.0. October, 3.7. Vancouver, British Columbia. April, 3.3. May, 2.8. June, 2.5. July, 1.2. August, 1.7. September, 3.6. October, 5.8. Victoria, British Columbia. April, 1.2. May, 1.0. June, 0.9. July, 0.4. August, 0.6. September, 1.5. October, 2.8. Source, Vanderleden et al. The Water Encyclopedia, 2nd edition. Chelsea, Michigan. Lewis Publishers, 1990. Defined scientifically, drought is not lack of rain. It is a dry soil condition in which plant growth slows or stops, and plant survival may be threatened. The earth loses water when wind blows, when sun shines, when air temperature is high, and when humidity is low. Of all these factors, air temperature most affects soil moisture loss. Daily Maximum Temperature, Fahrenheit. July, August Average. Eureka, California, 61. Medford, Oregon, 89. Eugene, Oregon, 82. Astoria, Oregon, 68. Olympia, Washington, 78. Seattle, Washington, 75. Bellingham, California, Washington, 75. Bellingham, Washington, 74. Vancouver, British Columbia, 73. Victoria, British Columbia, 68. Source, The Water Encyclopedia. The kind of vegetation growing on a particular plot and its density have even more to do with soil moisture loss than temperature or humidity or wind speed. And, surprising as it might seem, bare soil may not lose much moisture at all. Or no, it is next to impossible to anticipate moisture loss from soil without first specifying the vegetation there. Evaporation from a large body of water, however, is mainly determined by weather, so reservoir evaporation measurements serve as a rough guide of anticipated soil moisture loss. Evaporation from reservoirs inches per month. Location, Seattle, Washington, April, 2.1. May, 2.7. June, 3.4. July, 3.9. August, 3.4. September, 2.6. October, 1.6. Baker, Oregon. April, 2.5. May, 3.4. June, 4.4. July, 6.9. August, 7.3. September, 4.9. October, 2.9. Sacramento, California. April, 3.6. May, 5.0. June, 7.1. July, 8.9. August, 8.6. September, 7.1. October, 4.8. Source, the water encyclopedia. From May through September, during a normal year, a reservoir near Seattle loses about 16 inches of water by evaporation. The next chart shows how much water farmers expect to use to support conventional agriculture in various parts of the West. Comparing this data for Seattle with the estimates based on reservoir evaporation shows pretty good agreement. I include data for Umatilla and Yakima to show that much larger quantities of irrigation water are needed in really hot, arid places like Baker or Sacramento. Estimated irrigation requirements during growing season in inches. Location, Umatilla, Yakima Valley. Duration, April to October. Amount, 30. Willamette Valley. May to September, 16. Puget Sound. May to September, 14. Upper Rogue, Upper Umpqua Valley. March to September, 18. Lower Rogue, Lower Coquille Valley. May to September, 11. Northwest California. April to October, 17. Source, The Water Encyclopedia. In our region, gardens lose far more water than they get from rainfall during the summer growing season. At first glance, it seems impossible to garden without irrigation west of the Cascades, but there is water already present in the soil when the gardening season begins. By creatively using and conserving this moisture, Submaritime Northwest Gardeners can go through an entire summer irrigating very much, and with some crops irrigating not at all. End of Chapter 1. Chapter 2 of Gardening Without Irrigation or Without Much Anyway This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org Read by Betsy Bush, August 2009. Gardening Without Irrigation or Without Much Anyway by Steve Solomon. Chapter 2 Waterwise Gardening Science Plants Are Water Like all other carbon-based life forms on earth, plants conduct their chemical processes in a water solution. Every substance that plants transport is dissolved in water. When insoluble starches and oils are required for plant energy, enzymes change them back into water-soluble sugars for movement to other locations. Even cellulose and lignin insoluble structural materials that plants cannot convert back into soluble materials are made from molecules that once were in solution. Water is so essential that when a plant can no longer absorb as much water as it is losing, it wilts in self-defense. The drooping leaves transpire, evaporate, less moisture because the sun glances off them. Plants can wilt temporarily and resume vigorous growth as soon as their water balance is restored. But most vegetable species aren't as tough. Moisture-stressed vegetables may survive, but once stressed the quality of their yield usually drops markedly. Yet in deep open soil west of the Cascades most vegetable species may be grown quite successfully with very little or no supplementary irrigation and without mulching because they're capable of being supplied entirely to water already stored in the soil. Soil's water holding capacity. Soil is capable of holding on to quite a bit of water, mostly by adhesion. For example, I'm sure that at one time or another you have picked up a wet stone from a river or by the sea. A thin film of water clings to its surface. This is adhesion. The more surface area there is the greater the amount of moisture that can be held by adhesion. If we crushed that stone into dust we would greatly increase the amount of water that could adhere to the original material. Clay particles, it should be noted, are so small that clay's ability to hold water is not as great as its mathematically computed surface area would indicate. Surface area of one gram of soil particles. Particle type, very coarse sand. Diameter of particles in millimeters. 2.00 to 1.00 Number of particles per gram 90 Surface area in square feet centimeters. 11 Particle type, coarse sand. Diameter of particles 1.00 to 0.50 Number of particles 720 Surface area 23 Particle type, medium sand. Diameter of particles 0.50 to 0.25 Number of particles 5,700 Surface area 45 Particle type, fine sand. Diameter of particles 0.25 to 0.10 Number of particles 46,000 Surface area Particle type, very fine sand. Diameter of particles 0.10 to 0.05 Number of particles 772,000 Surface area 227 Particle type, silt. Diameter of particles 0.05 to 0.002 Number of particles 5,776,000 Surface area 454 Particle type, clay. Diameter of particles below 0.002 Number of particles 90,260,000,000 853,000 Surface area 8 billion Source Fof Henry D Fundamentals of soil science 8th edition New York John Wiley & Sons 1990 This direct relationship between particle size surface area and water holding capacity is so essential to understanding plant growth that the surface areas presented by various sizes of soil particles have been calculated. Soils are not composed of a single size of particle. If the mix is primarily sand we call it a sandy soil. If the mix is primarily clay we call it a clay soil. If the soil is a relatively equal mix of all three containing no more than 35% clay we call it a loam. Available moisture inches of water per foot of soil. Soil texture very coarse sand. Average amount 0.5 Coarse sand 0.7 Sandy 1.0 Sandy loam 1.4 Loam 2.0 Clay loam 2.3 Silty clay 2.5 Clay 2.7 Source Fundamentals of soil science Adhering water films can vary greatly in thickness but if the water molecules adhering to a soil particle become too thick the force of adhesion becomes too weak to resist the force of gravity and some water flows deeper into the soil. When water films are relatively thick the soil feels wet and plant roots can easily absorb moisture. Field capacity is the term describing soil particles holding all the water they can against the force of gravity. At the other extreme the thinner the water films become the more tightly they adhere and the drier the earth feels. At some degree of desiccation roots are no longer forceful enough to draw on soil moisture as fast as the plants are transpiring. Clay loam is called the wilting point. The term available moisture refers to the difference between field capacity and the amount of moisture left after the plants have died. Clay soil can provide plants with 3 times as much available water as sand 6 times as much as a very coarse sandy soil. It might seem logical to conclude that a clay garden would be the most drought resistant but there's more to it. For some crops deep sandy loam can provide just about as much useful moisture as clays. Sandy soils usually allow more extensive root development so a plant with a naturally aggressive and deep root system may be able to occupy a much larger volume of sandy loam. Ultimately coming up with more moisture than it could obtain from a heavy airless clay. The sandy loams often have a clay moisture rich subsoil. Because of this interplay of factors how much available water your own unique garden soil is actually capable of providing and how much you will have to supplement it with irrigation can only be discovered by trial. How soil loses water Suppose we till the plot about April 1st and then measured soil moisture loss until October. Because plants growing around the edge might extend roots into our test plot and extract moisture we'll make our tilled area 50 feet by 50 feet and make all our measurements in the center. And let's locate this imaginary plot in full sun on flat uniform soil and let's plant absolutely nothing in this bare earth and all season let's rigorously hoe out every weed while it is still very tiny. Let's also suppose it's been a typical maritime northwest rainy winter so on April 1 the soil is at field capacity holding all the moisture it can from early April until well into September the hot sun will beat down on this bare plot. Our summer rains generally come in insignificant installments and do not penetrate deeply. All of the rain quickly evaporates from the surface few inches without recharging deeper layers. Most readers would reason that a soil moisture measurement taken 6 inches down on September 1st should show very little water left. One foot down seems like it should be dry and in fact most gardeners would expect that there would be very little water found in the soil until we got down quite a few feet if there were several feet of soil but this is not what happens. The hot sun does dry out the surface inches but if we dig down 6 inches or so there will be almost as much water present in September as there was in April. Bare earth does not lose much water at all. Once a thin surface layer is completely desiccated, be it loose or compacted, virtually no further loss of moisture can occur. The only soils that continue to dry out when bare are certain kinds of very heavy clays that form deep cracks. These ever deepening openings allow atmospheric air to freely evaporate additional moisture. But if the cracks are filled with dust by surface cultivation even this soil type ceases to lose water. Soil functions as our bank account holding available water and storage. In our climate soil is inevitably charged to capacity by winter rains but then all summer growing plants make heavy withdrawals. But hot sun and wind working directly on soil don't remove much water. That is caused by hot sun and wind working on plant leaves making them transpire moisture drawn from the earth through their root systems. Plants desiccate soil to the ultimate depth and lateral extent of their rooting ability and then some. The size of vegetable root systems is greater than most gardeners would think. The amount of moisture potentially available to sustain vegetable growth is also greater than most gardeners think. Rain and irrigation are not the only ways to replace soil moisture. If the soil body is deep water will gradually come up from below the root zone by capillarity. Capillarity works by the very same force of adhesion that makes moisture stick to a soil particle. A column of water in a vertical tube like a thin straw adheres to the tube's inner surfaces. This adhesion tends to lift the edges of the column of water. As the tube's diameter becomes smaller the amount of lift becomes greater. Soil particles form interconnected pores that allow an inefficient capillary flow recharging dry soil above. However the drier soil becomes the less effective capillary flow becomes. This is why a thoroughly desiccated surface layer only a few inches thick acts as a powerful mulch. Industrial farming and modern gardening tend to discount the replacement of surface moisture by capillarity considering this flow an insignificant factor compared with the moisture needs of crops. But conventional agriculture focuses on maximized yields through high plant densities. Capillarity is too slow to support dense crop stands where numerous root systems are competing. But when a single plant can without any competition occupy a large enough area moisture replacement by capillarity becomes significant. How plants obtain water Most gardeners know that plants acquire water and minerals through their root systems and leave it at that. But the process is not quite that simple. The actively growing tender root tips and almost microscopic root hairs close to the tip absorb most of the plant's moisture as they occupy new territory. As the root continues to extend parts behind the tip cease to be effective because as soil particles in direct contact with these tips and hairs dry out the older roots thicken and develop a bark while most of the absorbent hairs slough off. This rotation from being actively foraging tissue to becoming more passive conductive and supportive tissue is probably a survival adaptation because the slow capillary movement of soil moisture fails to replace what the plant used as fast as the plant might like. The plant is far better off to aggressively seek new water in unoccupied soil than to wait for the soil its roots already occupy to be recharged. A simple bit of old research magnificently illustrated the significance of this. A scientist named Ditmer observed in 1937 that a single potted ryegrass plant allocated only one cubic foot of soil to grow in made about three miles of new roots and root hairs every day. Rye grasses are known to make more roots than most plants. I calculate that a cubic foot of silty soil offers about 30,000 square feet of surface area to plant roots. If three miles of microscopic root tips and hairs, roughly 16,000 lineal feet draws water only from a few millimeters of surrounding soil, then that single rye plant should be able to continue ramifying into a cubic foot of silty soil and find enough water for quite a few days before wilting. These arithmetical estimates agree with my observations in the garden and with my experiences raising transplants in pots. Lowered plant density, the key to water-wise gardening. I always think my latest try at writing a near-perfect garden book is quite a bit better than the last. Growing vegetables west of the Cascades recommended somewhat wider spacings on raised beds than I did in 1980 because I'd repeatedly noticed that once a leaf canopy forms plant growth slows markedly. Adding a little more fertilizer helps after plants bump, but still the rate of growth never equals that of younger plants. For years I assumed crowded plants stopped producing as much because competition developed for light. But now I see that unseen competition for root room also slows them down. Even if moisture is regularly recharged by irrigation and although nutrients are replaced, once a bit of earth has been occupied by the roots of one plant, it is not so readily available to the roots of another. So allocating more elbow room allows vegetables to get larger and yield longer and allows the gardener to reduce the frequency of irrigations. Though hot, baking sun and wind can desiccate the few inches of surface soil, withdrawals of moisture from greater depths are made by growing plants transpiring moisture through their leaf surfaces. The amount of water a growing crop will transpire is determined first by the nature of the species itself, then by the amount of leaf exposed to sun, air temperature, humidity and wind. In these respects the crop is like an automobile radiator. With cars the more metal surfaces the colder the ambient air and the higher the wind speed the better the radiator can cool. In the garden the more leaf surfaces the faster, warmer and drier the wind and the brighter the sunlight the more water is lost through transpiration. Dealing with a surprise water shortage. Suppose you are growing a conventional irrigated garden and something unanticipated interrupts your ability to water. Perhaps you are homesteading and your well begins to dry up. Perhaps you are a backyard gardener and the municipality temporarily restricts usage. What to do? First if at all possible before the restrictions take effect water very heavily and long to ensure there is maximum subsoil moisture. Then eliminate all interplantings and ruthlessly hoe out at least 75% of the remaining immature plants and about half of those about 2 weeks away from harvest. For example, suppose you've got a 4 foot wide intensive bed holding 7 rows of broccoli on 12 inch centers or about 21 plants. Remove at least every other row and every other plant in the 3 or 4 remaining rows. Try to bring plant density down to those described in chapter 5 how to grow it A to Z. Then shallowly hoe the soil every day or two to encourage the surface inches to dry out and form a dust mulch. You water wise person, you're already dry gardening. Now start furtigating. How long available soil water will sustain a crop is determined by how many plants are drawing on the reserve, how extensively their root systems develop and how many leaves are transpiring during the moisture. If there are no plants, most of the water will stay unused in the barren soil through the entire growing season. If a crop canopy is established midway through the growing season, the rate of water loss will approximate that listed in the table in chapter 1, estimated irrigation requirement. If by very close planting the crop canopy is established as early as possible and maintained by successive interplantings as is recommended by most advocates of raised bed gardening, water losses will greatly exceed this rate. Many vegetable species become mildly stressed when soil moisture has dropped about half the way from capacity to the wilting point. On very closely planted beds a crop can get in serious trouble without irrigation in a matter of days. But if that same crop were planted less densely it might grow a few weeks without irrigation. And if that crop were planted even farther apart so that no crop canopy ever developed and a considerable amount of bare, dry earth were showing, this apparent waste of growing space would result in an even slower rate of soil moisture depletion. On deep open soil the crop might yield a respectable amount without needing any irrigation at all. West of the Cascades we expect a rainless summer. The surprise comes that rare rainy year when the soil stays moist and we gather bucketfuls of shantrel mushrooms in early October. Though the majority of Maritime Northwest gardeners do not enjoy deep open moisture retentive soils I'll accept those with the shallowest soil can increase their use of the free moisture nature provides and lengthen the time between irrigations. The next chapter discusses making the most of whatever soil depth you have. Most of our region's gardens can yield abundantly without any rain at all if only we reduce competition for available soil moisture, judiciously furtigate some vegetable species and practice a few other water wise tricks. Would lowering plant density as much as this book suggests equally lower the yield of the plot? Surprisingly the amount harvested does not drop proportionately. In most cases having a plant density one eighth of that recommended by intensive gardening is in a yield about half as great as on closely planted raised beds. Internet readers in the print copy of this book are color pictures of my own irrigation-less garden. Looking at them about here in the book would add reality to these ideas. End of chapter 2 Chapter 3 Helping plants to need less irrigation Dry though the maritime northwest summer is, we enter the growing season with our full depth of soil at field capacity. Except on clay soils in extraordinarily frosty high elevation locations we usually can till and plant before the soil has had a chance to lose much moisture. There are a number of things we can do to make soil moisture more available to our summer vegetables. The most obvious step is thorough weeding. Next we can keep the surface fluffed up with a rotary tiller or hoe during April and May to break its capillary connection with deeper soil and accelerate the formation of a dry dust mulch. Usually weeding forces us to do this anyway. Also, if it should rain during summer we can hoe a rotary till a day or two later and again help a new dust mulch to develop. Building bigger root systems Without irrigation, most of the plant's water supply is obtained by expansion into new earth that hasn't been desiccated by other competing roots. Eliminating any obstacles to rapid growth of root systems is the key to success. So keep in mind a few facts about how roots grow and prosper. The air supply in soil limits or allows root growth. Unlike the leaves roots do not perform photosynthesis breaking down carbon dioxide gas into atmospheric oxygen and carbon. Yet root cells must breathe oxygen. This is obtained from the air held in spaces between soil particles. Many other soil dwelling life forms from bacteria to moles compete for the same oxygen. Consequently soil oxygen levels are lower than in the atmosphere. A slow exchange of gases does occur between soil air and free atmosphere but deeper in the soil there will inevitably be less oxygen. Different plant species have varying degrees of root tolerance for lack of oxygen but they all stop growing at some depth. Moisture reserves below the roots maximum depth become relatively inaccessible. Soil compaction reduces the overall supply and exchange of soil air. Compacted soil also acts as a mechanical barrier to root system expansion. When gardening with unlimited irrigation or where rain falls frequently it is quite possible to have satisfactory growth when only the surface 6 or 7 inches of soil facilitates root development. When gardening with limited water China is the limit and soil conditions permit many vegetable species are capable of reaching 4, 5 and 8 feet down to find moisture and nutrition. Evaluating potential rooting ability One of the most instructive things a water wise gardener can do is to rent or borrow a hand operated fenced post auger and bore a 3 foot deep hole. It can be even more educational to buy a short section of ordinary water pipe to extend the augers reach whether 2 or 3 feet down. In soil free of stones using an auger is more instructive than using a conventional post hole digger or shoveling out a small pit because where soil is loose the hole deepens rapidly where any layer is even slightly compacted one turns and turns the bit without much effect. Augers also lift the materials more or less as they stratified. If your soil is somewhat stony like much upland soil north of Centrelia left by the Vachon Glacier the more usual fenced post digger or common shovel works better. If you find more than 4 feet of soil the site holds a dry gardening potential that increases with the additional depth. Some soils along the flood plains of rivers or in broad valleys like the Willamette or Skagit can be over 20 feet deep and hold far more water than the deepest roots could draw or capillary flow could raise during an entire growing season. Gently sloping land can often carry 5 to 7 feet of open usable soil. However soils on steep hillsides become increasingly thin and fragile with increasing slope. Whether in urban, suburban, or rural gardener you should make no assumptions about the depth and openness of the soil at your disposal. Dig a test hole if you find less than 2 unfortunate feet of open earth before hitting the soil obstacle such as rock or gravel. Not much water storage can occur and the only use this book will hold for you is to guide your move to a more likely gardening location or encourage the house hunter to seek further. Of course you can still garden quite successfully on thin soil in the conventional irrigated manner. Growing vegetables west of the Cascades will be an excellent guide for this type of situation. Eliminating Plough Pan Deep though the soil may be any restriction of root expansion greatly limits the ability of plants to aggressively find water. A compacted subsoil or even a thin compressed layer such as Plough Pan may function as such a barrier. Though moisture will still rise slowly by capillarity and recharge soil above Plough Pan, plants obtain much more water by rooting into unoccupied damp soil. Soils close to river or on flood plains may appear loose and infinitely deep but may hide subsoil streaks of drowdy gravel that effectively stops root growth. Some of these conditions are correctable and some are not. Plough Pan is very commonly encountered by homesteaders on farm soils and may be found in suburbia too. But fortunately it is the easiest obstacle to remedy. Traditionally American croplands have been tilled with a mold board plough as this implement first cuts and then flips a 6 or 7 inch deep slice of soil over the soil the part supporting the plough's weight presses heavily on the earth about 7 inches below the surface. With each subsequent plowing the plough soil rides at the same 7 inch depth and even more compacted layer develops. Once formed Plough Pan prevents the crop from rooting into the subsoil. Since winter rains leach nutrients from the topsoil and deposit them in the subsoil, Plough Pan prevents access to these nutrients and effectively impoverishes the field. So why is farmers periodically use a subsoil plough to fracture the pan? Plough Pan can seem as firm as a rammed earth house. Once established it can last a long, long time. My own garden land is part of what was once an old wheat farm. One of the first homesteads of the Oregon Territory. From about 1860 through the 1930s the field produced small grains. The wheat became unprofitable probably because of changing market conditions and soil exhaustion. The field became an unplowed pasture. Then in the 1970s it grew daffodil bulbs, occasionally more plowing. All through the 80s my soil again rested under grass. In 1987 when I began using the land there was still a 2 inch thick very hard layer starting about 7 inches down. Below 9 inches the open earth is soft as butter as far as I've ever dug. On a garden sized plot plough pan or compacted subsoil is easily opened with a spading fork or a very sharp common shovel. After normal rotary tilling either tool can fairly easily be wiggled 12 inches into the earth and small bites of plough pan loosened. Once this laborious chore is accomplished the first time deep tillage will be far easier. In fact it comes so easy that I've been looking for a custom made fork that I've been looking for a few times. Curing Clay Soils In humid climates like ours sandy soils may seem very open and friable on the surface but frequently hold some unpleasant subsoil surprises. Over geologic time spans mineral grains are slowly destroyed by weak soil acids and clay is formed from the breakdown products. Then heavy winter rainfall transports these miniscule clay particles deeper into the earth where they concentrate. It is not unusual to find a sandy topsoil underlaid with a dense cement like clay sand subsoil extending down several feet. If very impervious a thick dense deposition like this may be called hard pan. The spading fork cannot cure this condition as simply as it can eliminate thin plough pan. Here is one situation where if I had a neighbor with a large tractor in subsoil plough it would be difficult for him to fracture my land three or four feet deep. Painstakingly double or even triple digging will also loosen this layer. Another possible strategy for a smaller garden would be to rent a gasoline powered post hole auger, spread manure or compost an inch or too thick and then bore numerous almost adjoining holes four feet deep all over the garden. Clay subsoil can supply surprisingly larger amounts of moisture than the sandy surface might imply but only if the earth is opened deeply and becomes more accessible to root growth. Fortunately once root development increases at greater depth the organic matter content and accessibility of this clay layer can be maintained through intelligent green maneuvering postponing for years the need to subsoil again. Green maneuvering is discussed in detail shortly. Other sites may have gooey, very fine clay subsoils almost inevitably with gooey, very fine clay subsoils as well. Though incorporation of extraordinarily large quantities of organic matter can turn the top few inches into something that behaves a little like loam, it is quite impractical to work in humus to adapt the four or five feet. Root development will still be limited to the surface layer. Very fine clays don't make likely dry gardens. Not all clay soils are fine clay soils, totally compacted and airless. For example, on the gentler slopes of the geologic old cascades those five hundred million year old black basalts that form the cascades foothills and appear in other places throughout the maritime northwest a deep friable red clay soil called in Oregon, jewelry often forms. Jory clays can be six to eight feet deep and are sufficiently porous and well drained to have been used in highly productive orchard crops. Water wise gardeners can do wonders with juries and other similar soils, though clays never grow the best root crops. Spotting a likely site Observing the condition of wild plants can reveal a good site to garden without much irrigation. Where Himalaya or evergreen blackberries grow two feet tall and produce small, dull tasting fruit there is not much available soil moisture. Where they grow six feet tall and the berries are sweet and good sized there is deep open soil. When the berry vines are eight or more feet tall and the fruits are especially huge usually there is both deep soil and a higher than usual amount of fertility. Other native vegetation can also reveal a lot about soil moisture reserves. For years I wondered at the short leaders and sad appearance of Douglas fir in the vicinity of Yelm, Washington to extreme soil infertility. When I learned that conifer trees responded more to summertime soil moisture than to fertility I obtained a soil survey of Thurston County and discovered that much of that area was very sandy with gravelly subsoil, Eureka. The Soil Conservation Service SCS a U.S. Government Agency has probably put a soil auger into your very land or a plot close by. Its tests have been correlated and mapped. The soils underlying the Maritime Northwest have been named and categorized by texture depth and ability to provide available moisture. The maps are precise and detailed enough to approximately locate a city or suburban lot. In 1987 when I was in the market for a new homestead I first went to my county SCS office, mapped out locations where the soil was suitable and then went hunting. Most counties have their own office. Using humus to increase soil moisture. Maintaining top soil humus content in the 4-5% range is vital to plant health, vital to growing more nutritious food and essential to bringing the soil into that state of easy workability and cooperation known as good tilth. Humus is a spongy substance capable of holding several times more available moisture than clay. There are also new synthetic long-lasting soil amendments that hold and release even more moisture than humus. Garden books frequently recommend tilling in extraordinarily large amounts of organic matter to increase a soil's water holding capacity in the top few inches. Humus can improve many aspects of soil but will not reduce a garden's overall need for irrigation because it is simply not practical to maintain sufficient humus deeply enough. Rotary tilling only blends amendments into the top 6 or 7 inches of soil. Rigorous double digging by actually trenching out 12 inches and then spading up the next foot theoretically allows one to mix in sufficient amounts of organic matter to nearly 24 inches. But plants can use water from far deeper than that. Let's realistically consider how much soil moisture reserves might be increased by double digging and incorporating large quantities of organic matter. The topsoil organic matter level in our climate is about 4%. This rapidly declines to less than 0.5% in the subsoil. Suppose inches thick layers of compost were spread and by double digging the organic matter content of a very sandy soil were amended to 10% down to 2 feet. If that soil contained little clay, its water holding ability in the top 2 feet could be doubled. Referring to the chart of soil moisture in chapter 2, we see that sandy soil can release up to 1 inch of water per foot. By dint of massive amendment, we might add 1 inch of available moisture per foot of soil to the reserve. That's 2 extra inches of water, enough to increase the time an ordinary garden can last between heavy irrigations by a week or 10 days. If the soil in question were a silty clay, it would naturally make 2.5 inches available per foot. A massive humus amendment would increase that to 3.5 inches in the top foot or 2, relatively not as much benefit as in sandy soil. And I seriously doubt that many gardeners would be willing to thoroughly double dig to an honest 24 inches. Trying to maintain organic matter levels above 10% is an almost self-defeating process. The higher the humus level gets, the more rapidly organic matter tends to decay. Finding or making enough well-finished compost to cover the garden several inches deep. What it takes to lift humus levels to 10% is enough of a job. Double digging just as much more into the second foot is even more effort. But having to repeat that chore every year or two becomes downright discouraging. No, either your soil naturally holds enough moisture to permit dry gardening or it doesn't. Keeping the subsoil open with green maneuvering. When roots decay fresh organic matter and large long lasting passageways can be left deep in the soil allowing easier air movement and facilitating entry of other roots. But no cover crop that I am aware of will effectively penetrate firm plough pan or other resistant physical obstacles. Such a barrier forces all plants to root almost exclusively in the top soil. However, once the subsoil has been mechanically fractured the first time and if recompaction is avoided by shunning heavy tractors and other machinery, green manure crops can maintain the openness of the subsoil. To accomplish this correct green manure species selection is essential. Lawn grasses tend to be shallow rooting while most regionally adapted pasture grasses can reach down about 3 feet at best. However, orchard grass called coltsfoot in English farming books will grow down 4 or more feet while leaving a massive amount of decaying organic matter in the subsoil after the sod is tilled in. Sweet clover, a biennial legume that sprouts one spring then winters over to bloom the next summer may go down 8 feet. Red clover, a perennial species may thickly invade the top 5 feet. Other useful subsoil busters include densely sewn umbilifairy such as carrots, parsley, and parsnips. The chicory family also makes very large and penetrating tap roots. Though seed for wild chicory is hard to obtain, cheap varieties of endive a semi cultivated relative are easily available and several pounds of your own excellent parsley or parsnip seed can be easily produced by letting about 10 row feet of overwintering crops form seed. Orchard grass and red clover can be had quite inexpensively at many farm supply stores. Sweet clover is not currently grown by our region's farmers and so can only be found by mail from Johnny's selected seeds. See chapter 5 for their address. Poppy seed used for cooking will often sprout. Sown densely in October it forms a thick carpet of frilly spring greens underlaid with countless massive tap roots that decompose very rapidly if the plants are tilled in in April before flower stocks begin to appear. If any of your new copies is a green manure crop be sure to till them in early to avoid trouble with the DEA or other authorities. For country gardeners the best rotations include several years of perennial grass, legume, herb mixtures to maintain the openness of the subsoil followed by a few years of vegetables and then back. See Newman Turner's book in more reading. I plan my own garden this way. In October after a few inches of rain has softened the earth I spread 50 pounds of agricultural lime per 1,000 square feet and break the thick pasture side covering next year's garden plot by shallow rotary tilling. Early the next spring I broadcast a concoction I call complete organic fertilizer seed growing vegetables west of Cascades or the territorial seed company catalog. Till again after the soil dries down a bit and then use a spading fork to open the subsoil before making a seed bed. The first time around I had to break the century old plow pan forking compacted earth foot deep as a lot of work. In subsequent rotations it is much much easier. For a couple of years vegetables will grow vigorously on this new ground supported only with a complete organic fertilizer but vegetable gardening makes humus levels decline rapidly so every few years I start a new garden on another plot and replant the old garden to green manures. I never remove vegetation during the long rebuilding under green manures but merely mow it once or twice a year and allow the organic matter content of the soil to redevelop. If there ever were a place where chemical fertilizers might be appropriate around a garden it would be to affordably enhance the growth of biomass during green manuring. Were I a serious city vegetable gardener I'd consider growing vegetables in the front yard for a few years and then switching to the backyard having lots of space as I do now I keep three or four garden plots available one in vegetables and the others restoring their organic matter content under grass. Mulching. Gardening under a permanent thick mulch of crude organic matter is recommended by Ruth Stout see the listing for her book and more reading and her disciples as a surefire way to drought-proof gardens while eliminating virtually any need for tillage, weeding and fertilizing. I have attempted the method in both southern California and western Oregon with disastrous results in both locations. What follows in this section is addressed to gardeners who have already read glowing reports about mulching. Permanent mulching with vegetation actually does not reduce summertime moisture loss any better than mulching with dry soil sometimes called dust mulching. True, while the surface layer stays moist, water will steadily be wicked up by capillarity and be evaporated from soil's surface. If frequent light sprinklings keep the surface permanently moist, subsoil moisture loss can occur all summer so unmulched soil could eventually become desiccated many feet deep. However, capillary movement only happens when soil is damp. Once even a thin layer of soil has become quite dry, it almost completely prevents any further movement. West of the Cascades, this happens all by itself in late spring. One hot, sunny day follows another and soon the earth's surface seems parched. Unfortunately by the time a dusty layer forms quite a bit of soil water can have risen from the depths and been lost. The gardener can significantly reduce spring moisture loss by frequently hoeing weeds until the top inch or two of earth is dry in powdery. This effort will probably be necessary in any case because weeds will germinate prolifically until the surface layer is sufficiently desiccated. On the off chance it should rain hard during summer, it is very wise to again hoe a few inches to rapidly restore the dust mulch. If hand cultivation seems very hard work, I suggest you learn to sharpen your hoe. A mulch of dry hay, grass clippings leaves and the like will also retard rapid surface evaporation. Gardeners think mulching prevents moisture loss better than bare earth because under mulch the soil stays damp right to the surface. However, dig down four to six inches under a dust mulch and the earth is just as damp as under hay. And soil moisture studies have proved that overall moisture loss using vegetation mulch slightly exceeds loss under a dust mulch. West of the Cascades, the question of which method is superior is a bit complex with pros and cons on both sides. Without a long winter freeze to set populations back, permanent thick mulch quickly breeds so many slugs, earwigs and sow bugs that it cannot be maintained for more than one year before vegetable gardening becomes very difficult. Laying down a fairly thin mulch in June after the soil has warmed up well, raking up what remains of the mulch early the next spring and composting it prevents destructive insect population levels from developing while simultaneously reducing surface compaction by winter rains and beneficially enhancing the survival and multiplication of earthworms. Mulch also enhances the summer germination of weed seeds without being thick enough to suppress their emergence. And any mulch, even a thin one makes hoeing virtually impossible while hand-weeding through mulch is tedious. Mulch has some unqualified pluses in hotter climates. Most of the organic matter in soil and consequently most of the available nitrogen is found in the surface few inches. Levels of other mineral nutrients are usually two or three times as high in the top soil however if the surface few inches of soil becomes completely desiccated no root activity will occur there and the plants are forced to feed deeper in soil far less fertile. Keeping the top soil damp does greatly improve the growth of some shallow feeding species such as lettuce and radishes but with our climate's cool nights most vegetables need the soil as warm as possible and the cooling effect of mulch can be as much a hindrance as a help. I've tried mulching quite a few species while dry gardening and found little or no improvement in plant growth with most of them. Probably the enhancement of nutrition compensates for the harm from lowering soil temperature. Fertigation is better all around. Wind Breaks Plants transpire more moisture when the sun shines. When temperatures are high and when the wind blows it is just like a drying laundry. Wind Breaks also help the garden grow in winter by increasing temperature. Many other garden books discuss wind breaks and I conclude that I have a better use for the small amount of words my publisher allows me than to repeat this data. Bindakal Brooks Winter gardening in the Maritime Northwest Sasquatch Books, 1989 is especially good on this topic. Fertilizing Fertigating and foliar spraying In our heavily leached region almost no soil is naturally rich while fertilizers, manures, and potent composts mainly improve the top soil. But the water wise gardener must get nutrition down deep where the soil stays damp through the summer. If plants with enough remaining elbow room stop growing in summer and begin to appear gnarly it is just as likely due to lack of nutrition as lack of water. Several things can be done to limit or prevent mid-summer stunting. First, before sowing or transplanting large species like tomato squash or big brassicas, dig out a small pit about 12 inches deep and below that blend in a handful or two of organic fertilizer. Then fill the hole back in. This double dicking process places concentrated fertility mixed 18 to 24 inches below the seeds or seedlings. Foliar feeding is another water wise technique that keeps the plants growing through the summer. Soluble nutrients sprayed on plant leaves are rapidly taken into the vascular system. Unfortunately, dilute nutrient solutions that won't burn leaves only provoke a strong growth response for 3 to 5 days. Optimally, foliar nutrition must be applied weekly or even more frequently. To efficiently spray a garden larger than a few hundred square feet I suggest buying an industrial grade 3 gallon backpack sprayer with a side handle pump. Approximate cost as of this writing was $80. The store that sells it, probably a farm supply store will also support you with a complete assortment of inexpensive nozzles that can vary the rate of emission and the spray pattern. High quality equipment like this outlasts many, many cheaper and smaller sprayers designed for the consumer market and replacement parts are also available. Keep in mind that consumer merchandise is designed to be consumed. Stuff made for farming is built to last. Increasing soil fertility saves water. Does crop growth equal water use? Most people would say this statement seems likely to be true. Actually, faster growing crops use much less soil moisture than slower growing ones. As early as 1882 it was determined that less water is required to produce a pound of plant material when soil is fertilized than when it is not fertilized. One experiment required 1100 pounds of water to grow 1 pound of dry matter on infertile soil but only 575 pounds of water to produce a pound of dry matter on rich land. Perhaps the single most important thing a water wise gardener can do is to increase the fertility of the soil especially the subsoil. Poor plant nutrition increases the water cost of every pound of dry matter produced. Using foliar fertilizers requires a little caution and forethought. Spinach, beet and charred leaves seem particularly sensitive to foliars and even to organic insecticides and may be damaged by even half strength applications. And the cabbage family coats its leaf surfaces with a waxy moisture retentive sealant that makes sprays bead up and run off rather than stick and be absorbed. Mixing foliar feed solutions with a little spreader sticker safer soap or if bugs are also a problem with a liquid organic insecticide like red arrow, a pyrethrum rhodorone nix eliminates surface tension and allows the fertilizer to have an effect on brassicas. Sadly, in terms of nutrient balance, the poorest foliar sprays are organic. That's because it is nearly impossible to get significant quantities of phosphorus or calcium into solution using any combination of fish emulsion and seaweed or liquid kelp. The most useful possible organic foliar is half to one tablespoon each of fish emulsion and liquid seaweed concentrate per gallon of water. Foliar spraying and fertilization are two occasions when I am comfortable supplementing my organic fertilizers with water soluble chemical fertilizers. The best and most expensive brand is Rapid Grow. Less costly concoctions such as Peters 2020 or the other grows don't provide as complete trace mineral support or use as many sources of nutrition. One thing fertilizer makers find expensive to accomplish is concocting a mixture of soluble nutrients that also contains calcium of vital plant food. If you dissolve calcium nitrate into a solution containing other soluble plant nutrients, many of them will precipitate out because few calcium compounds are soluble. Even Rapid Grow doesn't attempt to supply calcium. Recently I've discovered better quality hydroponic nutrient solutions that do use chemicals that provide soluble calcium. These also make excellent foliar sprays. Brands of hydroponic nutrient solutions seem to appear and vanish rapidly. I've had great luck with Dynagrow 795. All these chemicals are mixed at about 1 tablespoon per gallon. Vegetables that like foliar asparagus carrots, melons, squash beans, cauliflower peas, tomatoes broccoli, brussel sprouts cucumbers, cabbage, eggplant radishes, kale, rutabagas potatoes don't like foliar beets, leeks, onions spinach, chard, lettuce peppers like furtigation brussel sprouts, kale savoy cabbage, cucumbers, melons squash, eggplant peppers, tomatoes furtigation every 2 to 4 weeks is the best technique for maximizing yield while minimizing water use. I usually make my first furtigation late in June and continue periodically through early September. I use 6 or 7 plastic 5 gallon drip system buckets, see below set one by each plant and fill them all with a hose each time I work in the garden. Doing 12 or 14 plants each time I'm in the garden it takes no special effort to rotate through them all more or less every 3 weeks. To make a drip bucket, drill a 3 16th inch hole through the side of a 4 to 6 gallon plastic bucket about 1.25 inch up from the bottom or in the bottom at the edge. The empty bucket is placed so that the fertilized water drains out close to the stem of a plant. It is then filled with liquid fertilizer solution. It takes 5 to 10 minutes for 5 gallons to pass through a small opening and because of the slow flow rate, water penetrates deeply into the subsoil without wetting much of the surface. Each furtigation makes the plant grow very rapidly for 2 to 3 weeks. More I suspect it will result of improved nutrition then from added moisture. Exactly how and when to furtigate each species is explained in chapter 5. Organic gardeners may furtigate with combinations of fish emulsion and seaweed at the same dilution used for foliar spraying or with compost manure tea. Determining the correct strength to make compost tea is a matter of trial and error. I usually rely on weak rapid grow mixed at half the recommended dilution. The fertilizer you need depends on how much and deeply you place to nutrition in the subsoil. End of chapter 3 Chapter 4 of Gardening Without Irrigation This is a LibriVox recording all LibriVox recordings are in the public domain. For more information or to volunteer please visit LibriVox.org read by Betsy Bush October 2009 Gardening Without Irrigation or without much anyway by Steve Solomon Chapter 4 Water-wise Gardening Year-Round Early Spring The Easiest Unwatered Garden West of the Cascades most crops started in February and March require no special handling when irrigation is scarce. These include peas, early lettuce, radishes, kohlrabi, early broccoli, and so forth. However, some of these vegetables are harvested as late as June so to reduce their need for irrigation space them wider than usual. Spring vegetables also will exhaust most of the moisture from the soil before maturing making secession planting impossible without first irrigating heavily. Early spring plantings are best allocated one of two places in the garden plan. Either in that part of the garden that will be fully irrigated all summer or in a part of a big garden that can affordably remain bare during the summer and be used in October for receiving transplants of overwintering crops. The garden plan and discussion in Chapter 6 illustrate these ideas in detail. Later in spring sprouting seeds without watering. For the first years that I experimented with dry gardening I went overboard and attempted to grow food as though I had no running water at all. The greatest difficulty caused by this self-imposed handicap was sowing small seeded species after the season warmed up. Sprouting what we in the seed business call big seed corn, beans, peas, squash, cucumber, and melon is relatively easy without irrigation because these crops are planted deeply where soil moisture still resides long after the surface has dried out. And even if it is so late in the season that the surface has become very dry a wide shallow ditch made with a shovel will expose moist soil several inches down. A furrow can be cut in the bottom of that damp valley and big seeds germinated with little or no watering. Tillage breaks capillary connections until the fluffy soil resettles. This interruption is useful for preventing moisture loss in summer but the same phenomenon makes the surface dry out in a flash. In recently tilled earth successfully sprouting small seeds in warm weather is dicey without frequent watering. With a bit of forethought the water wise gardener can easily reestablish capillarity below sprouting seeds so that moisture held deeper in the soil rises to replace that lost from surface layers reducing or eliminating the need for watering. The principle here can be easily demonstrated. In fact there probably isn't any gardener who has not seen the phenomenon at work without realizing it. Every gardener has tilled the soil, gone out the next morning and noticed that his or her compacted footprints were moist while the rest of the earth was dry and fluffy. Foot pressure restored capillarity and during the night fresh moisture replaced what had evaporated. This simple technique helps start everything except carous and parsnips which must have completely loose soil to develop correctly. All the gardener must do is intentionally compress the soil below the seeds and then cover the seeds with a mulch of loose dry soil. Sprouting seeds that rest atop damp soil exactly like they lie on a damp blotter in a germination laboratory has covered petri dish. This dampness will not disappear before the sprouting seedlings has propelled a root several inches farther down and is putting a leaf into the sunlight. I've used several techniques to re-establish capillarity after tilling. There's a wise old plastic push planter in my garage that first compacts the tilled earth with its front wheel, cuts a furrow, drops the seeds, and then with its drag chain pulls loose soil over the furrow. I've also pulled one wheel of a garden cart or pulled a lightly loaded wheelbarrow down the row to press down a wheel track, sprinkled seed on that compacted furrow, and then pulled loose soil over it. Handmade Footprints Sometimes I sew large brassicas and kooker bits in clumps above a fertilized double-dug spot. First in a space about 18 inches square I deeply dig in complete organic fertilizer. Then with my fist I punch down a depression in the center of the fluffed-up mound. Sometimes my fist goes in so easily that I have to replace a little more soil and punch it down some more. The purpose is not to make rammed earth or cement but only to reestablish capillarity by having firm soil under a shallow fist-sized depression. Then a pinch of seed is sprinkled atop this depression and covered with fine earth. Even if several hot sunny days follow, I get good germination without watering. This same technique works excellently on hills of squash, melon, and cucumber as well, though these large seeded species must be planted quite a bit deeper. Summer, how to fluid drill seeds Soaking seeds before sewing is another water-wise technique especially useful later in the season. At bedtime place the seeds in a half-pint mason jar, cover with a square of plastic window screen held on with a strong rubber band, soak the seeds overnight, and then drain them first thing in the morning. Gently rinse the seeds with cool water two or three times daily until the root tips begin to emerge. As soon as this sign appears the seed must be sewn because the newly emerging roots become increasingly subject to breaking off as they develop and soon form tangled masses. Presprouted seeds may be gently blended into some crumbly moist soil and this mixture gently sprinkled into a furrow and covered. If the sprouts are particularly delicate or as with carrots you want a more uniform stand disperse the seeds in a starch gel tin and imitate what commercial vegetable growers call fluid drilling. Heat one pint of water to the boiling point. Dissolve in two to three tablespoons of ordinary cornstarch. Place the mixture in the refrigerator to cool. Soon the liquid will become a soupy gel. Gently mix this cool starch gel with the sprouting seeds making sure the seeds are uniformly blended. Pour the mixture into a one quart plastic zipper bag and scissors in hand. Go out to the garden. After a furrow with capillarity restored has been prepared cut small hole in one lower corner of the plastic bag. The hole size should be under a quarter inch in diameter. Walk quickly down the row dribbling a mixture of gel and seeds into the furrow. Then cover. You may have to experiment a few times with cooled gel minus the seeds until you define the proper hole size, walking speed, and amount of gel needed per length of furrow. Not only will pre-sprouted seeds come up days sooner and not only will the root be penetrating moist soil long before the shoot emerges but the stand of seedlings will be very uniformly spaced and easier to thin. After fluid drilling a few times you will realize that one needs quite a bit less seed per length of row than you previously thought. Establishing the fall and winter garden. West of the Cascades, germinating fall and winter crops in the heat of summer is always difficult. Even when the entire garden is well watered mid-summer sowings require daily attention and frequent sprinkling. However, once they have germinated keeping little seedlings growing in an irrigated garden usually requires no more water than the rest of the garden gets. But once hot weather comes, establishing small seeds in the dry garden seems next to impossible without regular watering. Should a lucky perfectly timed and unusually heavy summer rainfall sprouts your seeds, they still would not grow well because the next few inches of soil would at best be only slightly moist. A related problem many backyard gardeners have with establishing the winter and over winter garden is finding enough space for both the summer and winter crops. The nursery bed solves both these problems. Instead of trying to irrigate the entire area that will eventually be occupied by a winter or over winter crop at maturity, the seedlings are first grown in irrigated nurseries for transplanting in autumn after the rains come back. Where I desperately short of water I'd locate my nursery where it got only morning sun and sow a week or ten days earlier to compensate for the slower growth. Vegetables to start in a nursery bed Variety Fall winter lettuce Sowing date Mid-August Transplanting date Early October Variety Leaks Sowing date Variety Overwintered onions Sowing date Early mid-August Transplanting date December-January Variety Spring cabbage Sowing date Mid-late August Transplanting date November-December Variety Spring cauliflower Variety Winter scallions Sowing date Mid-July Transplanting date Mid-October Seedlings in pots and trays are hard to keep moist and require daily tending. Fortunately growing transplants in little pots is not necessary because in autumn, when they'll be set out, humidity is high, temperatures are cool, the sun is weak, and transpiration transplants will tolerate considerable root loss. My nursery is sown in rows about 8 inches apart across a raised bed and thinned gradually to prevent crowding, because crowded seedlings are hard to dig out without damage. When the prediction of a few days of cloudy weather encourages transplanting, the seedlings are lifted with a large sharp knife. If the fall rains are late and or the crowded seedlings are getting leggy, a relatively small amount of irrigation will moisten the planting areas. Another light watering at transplanting time will almost certainly establish the seedlings quite successfully. And finding room for these crops ceases to be a problem because fall transplants can be set out as a succession crop following hot weather vegetables such as squash, melons, cucumbers, tomatoes, potatoes, and beans. Vegetables that must be heavily irrigated. These crops are not suitable for dry gardens. Bulb onions for fall harvest. Celeric Celery, Chinese cabbage, lettuce summer and fall, radishes summer and fall, scallions for summer harvest, spinach summer. End of chapter 4