 Welcome, everyone, to the sixth session of our 10th session 2021 Field to Fork webinar series. My name is Julie Garden Robinson and I'm a food and nutrition specialist with NDSU Extension. I will be your host for today's webinar. Our upcoming webinars are featuring Janet Kanotl and ESU Extension entomologist and Joseph Lesnick, Extension Forester. We hope you are joining us for the entire series of 10 webinars. If you miss one, they will be archived within a day or two. As you can see, we are using the Zoom webinar function this year, and you will all be in listening mode today without cameras or microphones. People watching this live will be able to ask questions in the chat box. So you can go ahead and type your questions in the chat box and I will pose those questions to our speaker after his presentation today. And next I have a special request for all reviewers of the live talk and any of the archives to maintain our funding sources and offer these types of programs in the future. I ask that you please take the very short survey that will land in your email inbox shortly after today's talk. We will have random prize drawings, so you may receive a prize in the mail if you win. After submitting your survey, you will be redirected to a second survey to enter your name and mailing address. We offer two acknowledgments today. First to the USDA Agricultural Marketing Service for our field to fork funding. And we also have a contribution from Purdue University through a grant from the National Institute of Food and Agriculture. And we thank all the entities for your for their support and we also thank you for participating. It's time for our featured speaker and I'm very pleased to introduce Randy Nelson. Randy is an extension educator in Clay County, and his primary job responsibilities include education and outreach in the areas of home horticulture and agriculture production systems. Randy has been at the University of Minnesota extension Clay County since 2007. So thanks and welcome back. Thank you Dr. Garden Robinson and it's a pleasure to be back and thanks again for inviting me. Today we'll be talking about weed control in the home garden and as you think about this topic I know weed control is not always the most desirable topic to talk about but as all gardeners know it is extremely important in order to bring a good looking garden and also if you're growing vegetables one that is going to give you a bountiful produce. With that in mind, I'll talk briefly about the importance of weed control, and then I'll move right into weed control options which I have broken down into cultural and chemical under cultural control. We'll talk about hand cultivation, as well as mulch. So to start with when you think about weed control, these probably all come to your mind that you want to make sure that you remove all undesirable plants, also known as weed desirable plants. They're also blocking sunlight, they're taking up space, and they're also taking valuable nutrients that your desirable plants would be taking up otherwise. In addition to just what I have listed, they can also harbor insects that could damage some of your produce. For example, if anybody is growing potatoes, and if you've ever experienced Colorado potato beetle, you know that weeds in the nightshade family, and if you look at the photo on your right, that is a nightshade plant. They harbor Colorado potato beetle. And if you do happen to have nightshade, you know, maybe nearby, and you're growing potato or even if you're growing eggplant, it would be wise to do your best to get rid of nightshade. In addition to just insects, some of the weeds can also serve as host for diseases. For example, you're looking at common pigweed on the right, and pigweed is a host for verticillium wilt of tomato. In addition to everything I've stated, weeds also promote disease, which makes sense if you think about them, you know, taking up a bunch of space in your garden. They're also going to reduce air circulation, which means foliage is going to remain wet longer than what it should. Sometimes you'll see increased powdery mildew, which you'll see coming up here shortly. If you look at the photo on your right, you can see powdery mildew that is growing on some of these vines in the back. You're looking at a very weedy garden, and I'll talk a bit more about this. This was set up as a demonstration a few years back over in North Moorhead, but again, you can see a lot of lamb's quarter out here, a bunch of other weeds too. Another thing that weeds are going to do is that if you do happen to have, you know, maybe a pest that you have to control, or maybe you're trying to prevent a disease. It's going to make it very difficult to either put a spray on or potentially a dust on your desirable plants, just because there are other weeds that are out there. And probably most importantly, weeds are going to reduce the quality and yield of fruits and vegetables. And if you are growing just flowers, maybe you're not growing fruits or vegetables, they're going to reduce the amount of flowers to just because the plants are going to be smaller. And above all, it's going to create an unattractive garden. We're going to move on to our cultural controls. And the first one I want to talk about is the only one that you would do before planting. And this is called solarization. And if you look at the photo on the right, you can see when you use solarization, you're using clear plastic. And ideally, you're going to use two sheets of clear plastic that are anywhere from two to six mils thick. You're going to lay it over bare soil. And ideally that bare soil is going to be uniform, so you're not going to have a bunch of dips or voids underneath. If you want it level as can be, lay your plastic over, make sure you do a good job burying the edges around here. And you're going to do this during a summer fallow period. And generally you control, you can control weed seed in the top two to three inches of soil. You probably already have this come into your mind that there are some drawbacks with this one is that is in. I'm based out of Clay County, my office is in Moorhead so in my neck of the woods. This would take you a whole season. Basically, you're not going to be able to garden in this spot for a whole year or for a whole growing season, in order for that soil to get a high enough temperature to actually kill the weed seed. The other drawback to solarization is that it's only killing the weed seed in the upper few inches of soil because at least in my area, that's the soil that is going to heat up high enough to kill the weed seed. With that in mind, if one would then go out and do some type of tillage, maybe with a rototiller or if you're going to be maybe digging in the ground with a spade. If you're going, say more than three or four inches deep, you could then be bringing up weed seed. And basically the solarization isn't going to do you any good. Some of the other methods of cultural controls, as you can see here, is this your regular garden hoe or garden cultivator, which you can see in the first photo. And in the photo on the far right, you can see a rototiller, which some people use. The benefits of cultivation are numerous. One, you get immediate results because the moment you chop down a weed, it is going to start, you know, wilting and it's going to dry up right away. If you compare cultivation and again, whether it is a garden cultivator or, you know, some type of a tillage and implement like the rototiller. If you compare that with any type of herbicide, you can use hand cultivation. As often as you want, whereas any chemical application, your following label directions, which means, you know, there's always going to be an interval between your first application and then when you can apply it again. It's called hand cultivation. It's less dependent on whether if the weather is windy. It doesn't matter if it's going to rain soon. It doesn't necessarily matter either because you can still go out and do it. There is no residual control, meaning that once you go through and cultivate if more weed seed are exposed, eventually you're likely going to get more more weeds. And cultivation can also reduce soil structure. And if you focus on the photo on the far right, the rototiller, when you start doing tillage. That is when you can start reducing soil structure. And if you think about soil structure, when you have plants growing in the soil you have roots that are growing in there, you're going to have roots that would be considered well-structured. When you would dig into it, it's going to be nice and crumbly. The soil particles are going to be held together nice into some smaller pieces. And you also have a bunch of microorganisms that are in that soil too that are also helping build that soil structure. When you go through with a rototiller or any type of tillage where you're going in the ground a few inches, you're breaking up all that structure. And then the soil has to go through and that has to get redeveloped. Bear in mind, tillage is sometimes needed, but if possible, if you can limit tillage in your garden, you're going to be better off. And just want to draw your attention back to the person with the garden hoe. And just notice how they are just barely dragging that underneath the soil. They're bringing very, very shallow tillage with this garden cultivator. And that is what is, that's what would be recommended because they're not bringing up much for weed seed and they are essentially just cutting off the top of the weed. I'll talk a bit more about that as we move on. You know, again, whether you're using a garden hoe or some other type of device, you always want to start when the weeds are young. Ideally, somewhere around the two to four leaf stage or even smaller, if you can and like I mentioned previously, shallow cultivation is the key because the moment you start digging into that soil, you're bringing up weed seed. The reason for that is that a lot of our soils have quite a bit of weed seed that is in them inherently from from prior years. And when that weed seed, if it's still viable, if it's brought near enough to the soil surface, it can then receive sunlight. Maybe the temperatures are going to be more optimal for germination, then they're going to be able to germinate, emerge, and then give you a headache as time goes on. And I want to point out in this photo, this happens to be from our garden at home a few years back, if you notice the brown that is out here, that's not mulch that was applied, that's actually dead weeds. And the reason I bring this up is that when you remove your weeds and I just used a garden hoe and just lightly shave the weeds off at the soil surface because I was trying to control some annual weeds. And over on the far left, well, not the way far left, but the second row in here you can see a few pumpkins right here. The grasses that are growing along there are foxtail, which are annuals and if you just cut those off the soil surface, they're not coming back. These didn't have any seed heads, so I wasn't worried about the seeds maturing. And then I just left that across the soil surface because it's going to act as a mulch. And again, you don't necessarily have to, you know, keep your soil absolutely clean of all plant residue. Having the weeds laying on the soil surface, you know, when the rain falls, it does provide that rain something to hit, and it's not going to be compacting your soil as much or destroying that structure in the upper surface. When you start pulling out weeds, it's always a good idea to make sure you stay on top of it throughout the growing season. Later in the growing season, at least for me anyway, you're running out of time and, you know, sometimes you get weeds that escape. And the photo on the right, you're looking at common lamb's quarter, which is prevalent in this area along with a number of pigweeds. And if you look here, common lamb's quarter, an average plant can produce more than 70,000 seeds. If you think about that for a moment, if even 10% of those seeds survive and are, say, viable for the next year or two years, you have thousands of plants that could come up. And there are pigweed species that are in our area that you can get a single plant producing 100,000 plus seeds. And again, that is a lot of seed that can cause you a lot of headache down the road. So again, it's important to remove the weeds as you see them in your garden so they don't develop a seed head. Moving on to mulch. And I have the mulch section broke down into synthetic, which what I'm considering synthetic would be your plastics or landscape fabric, which is what's pictured on the right. And then I have organic and what I'm considering organic would be straw and wood and I'll talk about a few other organic mulches as well as we move on. So this is a piece of mulch and and this is mulch in general, including synthetic and organic is that you're going to have reduced weed germination and emergence, mainly because you're preventing light from reaching the soil surface, and you're creating a physical barrier any weeds that do happen to germinate and emerge, they're going to have to grow through the mulch if they can. And weeds that do make it through the mulch are generally easier to pull out. And another benefit of mulch is that it slows evaporation from the soil surface. A few additional benefits of mulches that the mulches will eliminate damage from deep cultivation. And I just want to give you an example of what I mean by that you're looking at some tomato plants, right here, and I happen to be using a plastic mulch over the soil surface and these were planted right into that. And then you can see some drip tape that is right here as well. With tomatoes, they tend to have a lot of their roots pretty near the soil surface. And if a person is out there, you know, trying to remove some weeds if you're going down a couple of inches, you're cutting into a lot of the roots of that tomato plant. The roots are cutting into a lot of roots, you're reducing the amount of water and nutrients though that plant can then take out of the soil, and you can ultimately reduce yield with mulch you don't have to worry about that. Another benefit of using a mulch is that you can prevent soil splash, or maybe prevent as a pretty strong word, you can at least lessen the amount of soil that is being splashed onto the foliage. So you can actually see a little bit of soil that is on top of the plastic in this photo right here. But even this plastic does a really good job of reducing the amount of soil splash and when you think about tomatoes. A lot of the tomato diseases, at least the foliage diseases are actually in the soil, or at least they can survive in the soil. So anything you can do to minimize that soil splash, you can also reduce the amount of foliage disease on your plants. The other interesting thing about mulch is that it will influence soil temperature. Some of the mulches can increase your soil temperature, others can suppress it. And I'll talk more about the influence of temperature as we go on. And also using a mulch is going to prevent soil crusting. And last thing I want to point out in this photo. If you look just to the left of this plastic, you can see the soil kind of has a little bit of white on top on there, then you can see a lot of cracks that are on there. And when the soil was freshly worked, it was nice and crumbly. This photo is taken in North Moorhead. But after several rains over the growing season, those soil particles at the surface were broken down by the rain drop into essentially sand silt and clay, which then the silt, the clays more or less formed a crust on top. And then when it dries, you get cracking. And this is really an issue. If you're growing small seeded plants like carrots, for example, because they're going to have a real tough time pushing through that crust. So again, the use of mulch can help to reduce or even eliminate in some cases soil crusting. Some of the drawbacks of mulch are that they need to be applied annually. And sometimes you might even have to make more than one application. If you look at this photo, the very look towards the top of it, you'll see an area that was mulched with wheat straw. And usually when you use wheat straw, it breaks down pretty quick, and you'll end up having to add more straw over the course of the over the course of the growing season. And in some cases, you might have to remove it in the end. If you look towards the bottom of that photo, you can probably just see some black plastic that's there. The black plastic, of course, in this case, it's not biodegradable. So it will have to be removed at the end of the year, which does increase the amount of work that a person has to put into their garden. I'm going to jump right into plastics. And plastic mulch is great to use around vegetable plants. And if you look at the photo on the right here, the far right row, you can see a partial row of peppers, and there's a row of tomatoes that are behind it. And then in the middle row, we have cucumbers, and then tomatoes are in the back. Tomatoes, cucumbers, peppers, if you're growing any melons, which would be your musk melon, your honeydew, watermelon, all of those plants like warm temperatures. And using plastic mulch can heat your soil. And these plants tend to do very well in that type of situation. When it comes to plastics, the real common ones are going to be clear and black. Although keep in mind, there are a lot of colors. For example, you can get blue, red, white, olive green, yellow, brown, reflective aluminum, and that's just a few. This photo just illustrates some of the colors that you can get. For example, you can see blue over here. We have red in the right here. And then as you go to the left on there, it looks like some white plastics. I remember reading a few reports that the use of red plastic could increase your tomato yield, and I'm not well versed enough in the different colors of plastic to let you know whether or not you could actually increase your yield. But just know that there is information out there about some of the plastics based on the color that they could potentially increase yield, and in some cases could decrease yield as well. The interesting thing about plastic is that it does have the ability to reflect, absorb, and transmit light. What is interesting that maybe not everybody knows is that clear plastic actually has the highest soil warming capacity. It allows visible light to penetrate, and it does not inhibit weed growth like black plastic. And if you look at the photo on there, you can clearly see the weed growth underneath. I think this is common personally if I'm not mistaken, that is growing underneath here. And granted, for the most part, the weeds aren't going to get real massive by any means, but using clear plastic, you certainly can and likely will get weed growth underneath. I just want to give you an example. This came from Penn State back in 2008. They just were checking soil temperatures under clear and black plastic and clear plastic. For example, the daytime soil temperature under clear plastic is usually 8 to 14 degrees higher compared to bare soil at a depth of two inches. And they did the same thing with black plastic. And the daytime soil temperature under black plastic is approximately 5 degrees higher compared to bare soil at a depth of two inches. And again, clearly you can see that the clear plastic, no pun intended, will increase the soil temperature more than what black plastic will. Another interesting thing to note is that you can purchase plastics that have special coatings on them. Sometimes they're referred to as selective reflective mulch or SRM for short. And sometimes you might see them listed as infrared transmitting or IRT mulch for short. And the IRT mulch will warm the soil intermediate to clear and black. And the nice thing about these is that they're pigmented. So they reduce the amount of visible light that actually moves through that plastic. And because of that, it will reduce the amount of weed growth beneath the plastic. I had mentioned earlier, landscape fabric under the synthetic mulches. And some people love using landscape fabric. It certainly some benefits to it. It will allow water and oxygen to pass through. Although, if you're going to use landscape fabric, if you could, it would probably be best if you could have it. So you had drip tape underneath because if you've ever poured water on the landscape fabric, yes, water and air does move through. But the water moving through is pretty slow. And if you have a raised bed, for example, a lot of that water can end up running off. So it would be best to use drip tape if you can, or you can always water through the planting hole. It is landscape fabric that is usually a little more expensive than plastic. But the one thing about landscape fabric is that if you're careful with it, you can reuse it for several seasons. When it comes to applying your synthetic mulch and again, whether that's plastic or landscape fabric, you want to do it as soon as you can in the spring of the year. And you want to apply it to a smooth seed bed. And ideally, your soil is going to be moist and you're going to do it during the warmest part of the day. And if you look at this photo right here, you can see these folks are laying a red plastic and you can see their roll of plastic in the back. So what they did, they just stretch this across their seed bed and note that they do have drip tape that was laid out. If you actually look to the bed just to the left of the one covered in red plastic, you can see a black strip of drip tape that runs the whole length. One important thing to note here is that you notice how that drip tape is offset a little bit to the right. And what they'll do when they actually come in here to plant with that drip tape offset, they can easily plant right down the middle without having fear of cutting into the black plastic tape. And you notice here too, the row on the left, you have a nice smooth surface on top. And what that smooth surface will do for you is it'll give you optimum plastic to soil contact, which is extremely important. In this case, their beds are not moist, but again if you can lay it plastic to a moist bed, that would be ideal. You can always water some, you know, maybe the night before and that should be enough time for that water to, you know, soak in and you're not having a muddy mess to deal with. Well, after they laid out their black or their red plastic, excuse me, if you look here, they're going through and they're probably digging down maybe three or four inches, and they're just throwing soil over the top. So essentially, they got trenches that they are, that they probably have pre-dog that they're filling in. And I did mention you want to do this during the warmest part of the day. And that's critical. And the reason is if you do it during the warmest part of the day, and if you get it relatively snug, what will happen is when the temperature starts to cool off, it is going to tighten up because of course, as it cools, that plastic is going to shrink and then it tightens up. If you put it, if you get it where it's really snug, there is potential you could rip your plastic, but I wouldn't be overly concerned about that if you're doing this by hand, but keep that in mind. If you do this during a cool part of the day, even though you might have it snug, what will happen when it warms up is that it'll be loose. So it is important that you do this if you can during the warmest part of the day. You can actually use plastic for even plants that you are seeding. You'd have a couple of options in this example right here I got some beans that are in the back and I seeded the beans and then I laid black plastic just right next to my row so I had a slit in there where the seeds could come up. The other option is you can lay your plastic and you could just poke holes and just seed right into or if you wanted to. They work really well for transplanting when you use plastic then you can just cut a slip in your plastic some people actually just burn a hole with a torch that's certainly an option to and then you can plant right into it. And like I mentioned before, when you're using plastic, it's always best to use drip tape and going back to the photo I showed you earlier the tomato plants right here. What we have right here is drip tape that is running along. And this is where the drip tape connects to what is the main line and this irrigation system folks is a real real simple setup. All that was needed for this is the drip tape, and then you have what's considered your main line right here. So this main line just runs back to a pressure reducer and that pressure reducer is hooked up to a garden hose. And all I have to do is turn on our hydrant and the water hits that pressure reducer the PSI or pounds per square inch drops down to 15. And then that water flows through the main line and then into the drip line it's a real slick way to water your plants in the garden. And that's a relatively inexpensive setup. And if you're real careful with your drip tape, you can use that for more than one year, and your main line that I that I mentioned earlier. I think I've been using main line probably for the same main line for about seven or eight years already. As I mentioned in the earlier in the presentation that the plastic is likely going to have to be removed at the end of the growing season. You have plastic that is not biodegradable and it's in good condition if you're careful, you can roll that back up and reuse it the following year I've had good luck doing that. But I do want to point out that there are biodegradable plastics, and this photo was taken back in September of 2014. And this is a trial that Dr. Chi-Wang Li was conducting at at NDSU. And he was growing cucumber, and he had four different mulch treatments. On the far left he had clear, and then he had biodegradable. There was a control which didn't have any plastic applied to it, and then black plastic on the far right and I just want to focus on the biodegradable one. What you can see on September 19 that there's still a little bit of that plastic left, but it is it is breaking down pretty good and they've had, they have made some pretty big strides in biodegradable plastic since 2014. And some of them now are able to actually break down at the end of the growing season where you're not out having to pick up pieces so biodegradable plastic could be an option. When it comes to organic mulch, as you can see in the photo here we're looking at wood chips, organic mulch will over time add nutrients and organic matter back to the soil. It will help to improve soil structure. Again, mainly it's protecting the soil surface from from the impact of raindrops, as well as drying out from the sun. I do want to mention that as the mulch decomposes some of the soil nitrogen that's in contact with the mulch is not going to be readily available to the plants and the reason for that microorganisms in the soil are going to be using that nitrogen as a food source. And then they're going to slowly break down the mulch. All that said, you might notice nitrogen deficiency in some of the plants and usually that's going to be a yellowing of your older leaves or the lower leaves on the plants. I do want to point out though, if you're just applying organic mulch to the soil surface and you're not working it into the soil, you shouldn't have any issues. I've used a lot of wood mulch, a lot of straw mulch over the years in gardens and landscape plantings and I've never witnessed a nitrogen deficiency. The issue is going to come in if you were to till in the organic mulch if it wasn't broken down. For example, if you till in wood chips, you can certainly have an issue because those wood chips have a very high carbon to nitrogen ratio and it just takes a lot of time for that to break down. And again, if you leave them on the soil surface, you shouldn't have any issues. When it comes to organic mulch, you really have limitless possibilities. Some of the ones that I want to briefly mention are going to be compost, leaves, straw or hay, wood chips. Some people call that shredded bark and finally pine needles. I left off grass clippings, although some people have real good luck using grass clippings. If possible, return your grass clippings to your lawn because your lawn is going to get more benefit out of those grass clippings than what your garden is. Although if you are using grass clippings, just make sure that you are not using any herbicides or you didn't recently use any herbicides on your lawn because if you did, those herbicides can then be in those clippings and then potentially cause you a problem in your garden. So if you did use an herbicide, it's always best to not use those grass clippings in your landscape bed or in your home garden. Compost is great to use around vegetables as well as fruit plants. You can use it around flowers too. Oftentimes compost is going to be laid right over the soil surface at a depth from anywhere from two to four inches. And I want to point out one thing. You notice the picture on the lower left side, you see a lot of steam that is rising up from these piles. That compost is not finished yet. It's still in the heating process. When you're using compost, ideally you want to make sure that it is fully decomposed or maybe I should say fully cured. If you look over here on the far right, you can see some nice piles. You're not having any steam. And when you grab a finished compost and you smell it, it really has just an earthy smell to it and you really can't make out any of the organic material that it was once composed of. And again, it can make great compost. And I should say it can make great mulch over your plants. Leaves are certainly an option. They can be used around vegetable and fruit plants. You can go a little bit deeper with leaves, maybe three to four inches deep. And it's best if you can run them over with lawnmower first, get them chopped up. A couple of drawbacks on leaves. One, if you get a really good wind after these were applied, you might lose all your mulch. The second drawback is that they're going to break down relatively quick in the garden. So you may find yourself having to resupply and again to make sure you keep your mulch layer. And maybe another drawback, depending on where you live, you might not have many leaves. Straw or hay make a wonderful mulch. And about the same depth that you would use for leaves three to four inches. One thing I want to point out is that try to make sure that there are no weed seed in there. And by weed seed, that could also be the, for example, if you're using wheat, that would also be the wheat seed. For example, if all the wheat wasn't taken out of the straw or essentially wasn't harvested, and it was still in the straw. Well, those weed seeds are then going to germinate and now all of a sudden it is becoming a weed problem in your garden. So if you are using straw or hay, just make sure that it is free of any, any weed seed, if possible. Even chips or shredded bark work wonderful, especially if you have perennial fruit plants. I have perennial vegetables on here. Some people consider rhubarb a fruit, others a vegetable. But it obviously rhubarb comes back every year so you're not really killing around your rhubarb plants. But therefore they, again, the wood mulch works wonderful because you should be able to get probably at least two or three years out of a single application. And you can go a depth of three to four inches, depending on where you're at. If it's, you know, if you're a little wetter you can certainly go around three inches if it's pretty dry you could certainly go with with four inches of wood mulch. If you're using needles, depending on where you're located you might have a lot of access to pine needles. These work well again for vegetables that are perennial, as well as your perennial fruit plants and the reason for that is that pine needles to are going to last for a while, and you can lay this down to a depth of about three to four inches. A common question that comes up with using needles, will it affect the soil pH and again I'm based in Clay County, my office is in Moorhead. And I know the soil pH right around the Moorhead area, you know we're anywhere probably from 7.6 and in some cases maybe up to an eight or an 8.1. Pine needles would not lower our soil pH to a point where it's going to cause any issue. So if you have a higher pH soil again something that is around that 7.5, 7.6, you shouldn't have an issue but again bear in mind I can only speak to my area with with the soils that are common in in Clay County. And again in my area, you certainly would not have an issue using pine needles if you have a different soil where maybe you're a bit on the acidic side. I would, you may want to use a little bit of consciousness before using pine needles. I also wanted to mention sawdust, because again depending on where you're located you might have access to an abundance of sawdust especially if you happen to be near a sawmill. So sawdust just like pine needles and wood mulch work great around your perennial plants just because it's going to last for a couple of seasons. If you do have access to sawdust, make sure that it's been composted for one year and the reason for that there are a lot of chemical compounds in fresh sawdust that could cause harm to your plants. And usually after a year of composting or basically just have it in the pile, those chemicals are going to be gone and you should be able to safely apply it around your plants without an issue. And sawdust since it is a pretty fine material, and it can mat together pretty well, you don't want to go much deeper than two inches. And obviously a drawback with sawdust, it's pretty light, and if you apply it you get a really good wind, you may end up losing a lot of what you put down. Another one that is common, some people like to use this newspaper. And usually people are putting down either strips of newspaper or if you look at this photo you can see actually basically whole pieces of newspaper are being laid down and oftentimes people will put together four or six sheets and lay that over the soil surface. And if you look at the bed in the back, they actually lay down newspaper and then put some straw mulch over the top of it that tends to help hold it down because obviously with newspaper, it could blow around if it dries out unless it has something on top of it or if you maybe have it staked down. But again, newspapers are certainly an option. I want to talk a little bit about when to apply organic mulches. And generally speaking, when you're planting your cool season vegetables, if you think about onions, broccoli, cabbage, once you either seed these or if you transplant these, you can go ahead and apply your organic mulch because these plants like cooler temperatures, and you're not going to cause any problem. With our warm season vegetables, think of tomatoes and peppers. You want to apply your organic mulch when that soil temperatures have warmed up enough and usually the rule of thumb is a temperature around 65 degrees Fahrenheit. I want to draw your attention here to a demonstration garden I set up years back. Gosh, I think this was back in 2009, if I remember correctly, there was a garden I was doing some work at in North Moorhead. And if you see my yellow lines, that is showing you the row of summer squash. Obviously that is not a straight line, because the piece of ground I had, it was a little bit misshapen, and while my row was just not that straight either. What you're looking at are, again, all the the same plant so again we have summer squash through here and think we had some onions all the way here and some radish that are now seeding out and there are some beans on the far left. The only difference in these plots is the mulch treatment. And these plants were all put in the ground on June 3, and I believe this is back in 2009. And the picture you're looking at this was taken in about mid July. So you can draw your attention to the far back if you can kind of see part of the car that is in the picture here, but we have straw mulch. This straw mulch was laid down after the soil temperature at a four inch depth was 65 degrees. Then as we come down this picture here, we have a bare soil plot. Then we have black plastic. And then we have some more straw mulch. The black plastic, of course, was laid down right after planting. And again, black plastic is going to increase your soil temperature. The straw mulch, like I mentioned, was placed right after planting. And when this garden was planted on June 3, the four inch soil temperature was only 59 degrees Fahrenheit. And I want you to note, I'm hoping that you can notice the big difference in plant size. Again, this is summer squash, really with the straw when the soil temperature was 65 degrees at a four inch depth, the bare plot, and then the black plastic. Those summer squash are above the same size, but you probably notice a significant reduction in size with the plot that had the straw mulch laid right after planting. And this photo, like I said, was taken in mid July. And I think I took this, it was in the late afternoon, probably around six o'clock or so. And I also took the soil temperature at that time. And for the three plots, the straw mulch in the back, bare soil, black plastic, the four inch soil temp was 77 degrees. And the four inch soil temp on this plot with the straw that was laid down right after planting was only 69 degrees. And again, just want to illustrate the importance of laying your organic mulch at the right time. My feeling is that the straw mulch kept the soil temperature cooler for the plot in the foreground, and that is why those summer squash plants are so much smaller when you compare it with the straw mulch plots in the back, where it's the same size as essentially the bare soil and the black plastic. I wanted that to throw that out there. You'll see you can see in what an impact organic mulch can play on warm, loving plants again like like squash. If it's applied, if it's applied too early when the soil temperatures aren't warm enough because again organic mulch will suppress soil temperature. Alright folks, the last thing I want to talk about here are herbicide options and there certainly are herbicide options that homeowners can use. Probably one of the most common are going to be your, what are known as a pre emergence herbicide and these generally are are put down prior to any weed seed germination because they're not going to have any impact on plants that are already up and growing prior to any emergence what they'll do, they more or less form a barrier in the soil maybe that top inch or so. And as that weed seed begins to germinate and grow it'll contact that herbicide that herbicide moves into the plant, and then it'll cause its damage to the plant and the plant eventually dies. One of the most common pre emergent herbicides that homeowners have access to is trifleurilin. The other one is corn gluten meal and corn gluten meal would be your organic option and trifleurilin would be certainly not an organic option. I have side by side here pictures of just a portion of the herbicide label and the only reason I'm showing these to you, just this for educational purposes just to illustrate the importance of following directions on here. And I want to draw your attention first if you look under for use on vegetables and hopefully you can see my blue arrow that popped up, you notice before seeding. Which means that before seeding broccoli Brussels sprouts and I'm not going to read them all, you can apply this particular product. I'm not going to cause any impact to those plants. If you notice the next one down after seeding or transplanting. It says after seeding or transplanting cantaloupe cucumbers watermelons apply after plants have developed five or more leaves. And then we're just going to skip down to the last one where it says before transplanting celery broccoli Brussels sprouts and whatnot. My point is, is that it's, it's really important to know what you're seeding and when you should apply your pre emergence again some of these plants before you apply before or, you know when you seed others you have to wait long enough until your plants are established before you put it down. I have seen cases where pre emergence have been used and inappropriately and it ended up ruining that particular crop because it was just not able to come up because that herbicide had an impact on that germinating seed. And it essentially killed most of the crop. And I also want to point out the corn gluten meal label and again this is just a portion of it on the far right and hopefully you see my blue arrow that popped up here. On this one notice that it doesn't say anything about the actual types of plants for example you don't see Brussels sprouts or anything like that. All you see here it says when your vegetable sprouts have true leaves and are two to three inches tall, it's safe to apply the product. Again, the only purpose of showing you these two is just to stress how important it is to read the label to make sure you're applying it appropriately. When it comes to post emergence herbicides, meaning that you're going to apply the herbicide to weeds that are already there. There's not that many products available to the home gardener in particular for broadleaf weeds. If you look at my photo on the right. That's Canada thistle that happened to be coming up in a opening in some plastic mulch. There are products that are available on the market but again for the home gardener, they're not very economical. The one product that you may be able to use and you might find some usefulness would be a non-selective herbicide. And one the common name of the active ingredient would be glyphosate with any non-selective and that means that it's essentially killing anything that you apply it to. You have to use extreme caution when you apply the product so that you only contact the weed that you are trying to kill because if it would drift or move over to your desirable plants it's going to cause damage to them too. And it's also important to note that when you're looking for a non-selective, make sure that it's labeled for use in a vegetable garden or around fruit plants. You got to make sure that it says that on the label then you should be fine. But again you want to use extreme caution because otherwise you're going to cause damage to your desirable plants. When it comes to grass control, there are more options that are available to the homeowner. One of the common names of the active ingredient that you can find at a lot of garden centers is sephoxidin. And this particular product, it's a grass control product, you can apply it over the top and if you look at this photo here, we have some cone flowers in the foreground here and a lot of quack grass. You could apply it over the top and it's going to take out the grass without causing any harm to the flower in this case. So if you have areas of your garden, whether it be a vegetable, maybe a fruit garden or a flower garden, all hope is not lost because you could look at using one of the selective grass herbicides in that situation. Just make sure that if you're using it as an over the top, meaning that you're applying this as a spray over the top of the area, that it's not going to cause any harm to your desirable plants. And when you look at the label, it'll tell you what plants you can apply it over the top to. With that folks is going to wrap it up here that weeds can be successfully managed. And remember, look at your cultural control options first we talked about cultivation, we also talked about using mulch. And then, when you've used those, if you have some real difficult to control weeds, always remember that you do have some chemical options. With that, I would love to take any questions that you may have. I have a lot of questions. And I think some of these you already answered, like the reason for clear versus black plastic so I think you covered that. Garb says, I get thousands of elm tree seeds which fall. Any thoughts on the best ways to deal with them. Oh, gosh, that is a, that is a great question. I don't have any real good ideas. Other than you might want to look at some of the pre emergence options like I had mentioned trifleural and that could be an option you'd have to look at the label to see if it has any effectiveness on on elm seeds. But that could be an option if you're dealing with a lot of them you might be able to use that in your garden. The only other thought is, I don't know if this is practical or not. But if you could cover your, you know, the area where they're blowing in, when those elm seeds are falling, you know, that could be another option to buddy. But again, I don't know if that's going to be practical or not. Sue asks, what inch spacing should there be between holes and drip system holes. Great question because with with the irrigation or with the drip tape, you know I think I've seen six inch I think is real common eight inch. I've been using eight inch just because that was what the supplier had in stock I've had good luck with that. You probably would be okay with that some people will use a smaller spacing just because you get more. The water is. It's not as far apart but if you run your irrigation long enough. You know your plants should be whetted appropriately it's really going to come down to to what you're growing. If you're using it with tomato plants or pepper plants for your spacing is a foot. For plant for peppers or maybe two feet apart for tomatoes and you have an eight inch spacing on your emitters for your drip tape, you'd be fine with that you could probably even go, you know if you even had a foot spacing you could certainly do that too. If you're using it for, you know, save some closer space plants, maybe beans or radish or lettuce, maybe getting drip tape that had a little bit closer emitters. That would be an idea to Kelly is wondering if you should till the straw into the soil in the fall. You, you certainly could till it in in the fall, if, if there's not a lot on the soil surface because you know depending on when you do it if it's early enough in the fall we have a say a long fall where the temperatures are a bit warm where those microbes are still active. If everything down come springtime, you're going to be fine but if it happens to be a bit cooler and you don't get much breakdown in your soil. You could have some issues with some nitrogen being tied up. So it's, you're going to have to use your best judgment I would say if there's not a lot of straw on the surface, go ahead, kill it in. If it's a pretty thick layer of straw on top, you might be better off just raking it off the best he can, and then do any of the the tillage that is needed. Aaron is wondering if it is best to till a garden in the fall and and then again in the spring or leave it until only in the spring. Alright, another great question. When it comes to tillage. I would look at why one why you're you're telling because you may not have to. For example, if you're not having to contend with a lot of roots maybe coming from, I don't know if you got a windbreak or something that you're worried about or you know, maybe some trees that are mature trees that are close you're not worried about those roots and invading your garden. You may not have to tell it all you might just be able to maybe just work up some rows where you're planting and maybe also you're adding in fertilizer where you're having to incorporate that some let's just assume you're adding fertilizer you need to incorporate that. I would just do one tillage pass in the in the spring of the year and call it good and I assume there's maybe cases where you'd want to tell twice, none come to mind right now so I think you could easily get by with just once in the spring of the year. Okay, here's an interesting question from Lila. The previous owners of my home put plastic dome covers over the window wells. I had lots of weeds last season, including oxalis around the edge of the window wells under the domes. Would landscape fabric covered by pea gravel be a good option in place of unscrewing covers and pulling the weeds. You might have an option with that, although if you have oxalis and maybe some other difficult to control weeds. Even if you do a perfect job laying down your landscape fabric covering it up with P rock. The very edges of the window well, they may be able to have enough light and probably enough moisture where they could actually germinate and emerge and then grow right along your edges which would then require you to go in and manage those. So even with the landscape fabric and P rock you can certainly cut down on the amount of weeds but bear in mind they can still come up around the edges. Putting you through your paces here today or handy. Dwight is wondering, when wheat or straw bales have been used and herbicide has been applied. Will there be a risk residue that may affect the plants. Great question. And I, I don't have a good answer for that question although here's what's coming to mind. Right now, and that is any of the herbicides or various pesticides maybe it was a fungicide or something like that that was used. There's going to be a pre harvest interval for the farmer that they would have to follow, assuming that was all followed they harvested their wheat. When it was, you know, safe for them to do so. So I sure wouldn't think you would have any issues with any. You know, any residual being left in the straw that would cause harm in your, in your garden. If it's a concern. I would certainly ask the person that you're purchasing from just to find out what they had used and if they can give you the product, you could certainly look that product up, and then there might be a interval in there but again I'm thinking that you're likely going to be fine. Sue asked about handouts for this session I believe your PowerPoint slides will be posted as a PDF. And if you go to either University of Minnesota or and ESU extension, you're going to find a lot of information about weeds, correct. That is correct. Yes. Last question and then I'm going to refer the rest of the folks who have questions maybe to write to you directly if that's okay. Yes, that would be just fine. All right, so last one. This is about the local landfill and the compost that's available. And Catherine says the local landfill says their compost is processed for three years before it is available to residents. Is it long enough to destroy herbicide residue. Great question. You know in a perfect world, there shouldn't be any herbicide in the turf grass, going into the compost pile because everybody would be looking at their label directions and it'll say when you apply the herbicide you have to wait this for this many moans before you can catch your clippings before you can use them as compost. Obviously, that is that's not the case so it's very likely you're going to get clippings that are contaminated with herbicide after three years. Gosh, I would sure think most of them would already be would be out, and it would be safe to use. One thing you can do if you're concerned. You can always get a sample of of compost or if you get compost ordered in, just take a sample of it. And you can maybe mix it with potting soil 5050 by volume, and then use just potting soil alone and grow some very sensitive plants, and that would be your green bean or tomatoes. It should be grow fine in your mix. It should be fine and the reason to have to your mix and your basically your control you know there's nothing in your the potting soil, you would just want to make comparisons and if the growth looks the same. I think the compost should be just fine. Well with that will wrap it up for today and I want to thank you Randy for your excellent presentation. I learned a lot and I'm anxious to get outside and garden. And I want to thank everyone else for attending. And please join us next week. So thanks again Randy. Thank you Julie.