 Using the sun to dry grain requires little investment and is environmentally friendly. This video shows you how to sun dry grain and explores the many options for using this method. What is sun drying? Sun drying is a traditional method of drying paddy. The sun heats the surrounding air and thus increases the rate of water evaporating from the grains. So why sun dry? Simply put, sun drying is cheap compared with mechanical drying. It is also environmentally friendly since it uses the sun as the heat source and therefore produces no carbon dioxide or pollution. Now that we know what sun drying is, let's learn how to do it. First, spread the grains in thin layers on the drying surface. The pile should be 2 to 4 cm high. Before faster drying, place the grains and panicles in well aerated or windy areas. You will need to mix the grain frequently, at least every 30 minutes. Make sure that you monitor the grain temperature and moisture content using thermometers and moisture meters. Shade or cover the grain when grain temperatures are above 50 degrees Celsius to avoid overheating. Make sure you collect or cover the grain when it rains and at night, because dried grain that becomes moist usually cracks. Another tip to minimize cracking is to use sun drying for first stage drying. Reduce water from the outer layer of the grain to 18% moisture content. This grain can be safely stored for two weeks. Use another drying system to reduce moisture further. This dries the rice at a slower rate and the grains have less chances of cracking. Finally, keep animals off the grain and avoid drying grain on public roads as the grain can get dirty or hinder traffic and cause accidents. Although sun drying is inexpensive and simple, it has some limitations. Because it is not possible during rain or at night to dry the grain, delays in drying lead to excessive respiration and fungal growth causing grain losses in the yellowing. Sun drying is labor intensive and has a limited capacity. Another problem is that controlling temperature is difficult. Also overheating can result in low milling quality caused by cracked grains. Now that you know the basics of sun drying, let us look at four methods of drying grain under the sun. This is the traditional method for pre-drying hand harvested crops before thrashing. To feel dry, place cotton plants on the ground or on racks. Field drying has limitations, however. At night, grains can get wet from the soil and from wet straw. There is limited air circulation and drying, so grain quality can rapidly deteriorate if you aren't ensuring optimum airflow. Field drying is another traditional smallest scale method used by farmers. In this method, you place tight bundles of panicles on pavements or mats or hang them from frames. You will need to manually harvest the panicles which sometimes results in an even drying since grains inside a panicle dry slower than grains outside. This is a small-to-medium-scale method of sun drying for farmers, groups, and contractors. It's a hygienic method that allows quick collection and mixing by placing thrust grain on nets, mats, or canvass. There are some costs involved for the net, mat, or canvass, if you decide to use this method. One problem is rewetting and pollution from the ground when using nets. Drying on pavements is a method used for medium-to-large-scale drying. For pavement drying, place thrust grain on pavements made specifically for drying. Mixing and collecting can be partially done by mechanization. Due to the large size of this setup, labor can be more effectively used when pavement drying. One recommendation to improve the system is to use pavements with elevations for the grains and drainage channels for rainwater. Although the pavement method is effective, grain is vulnerable to contamination from stones and dirt. You will also need capital for pavement. Those are the basics of sun drying. Now you can wait for the sun to rise while you choose a method that suits you best.