By Tracey Allen, Colorado State University Cooperative Extension Master Gardener, Denver County
It takes a staunch gardener to dig up a lawn and turn it into a garden, unless you do it the "no till" way. In a matter of hours, this method allows you to turn an unused sod area into a raised bed garden.
Locate an area of unused lawn that receives at least six hours of full sun each day. Mark off the area with a garden hose, then use a spade to create an outline just inside the hose. Cut the sod into one cubic foot pieces, then turn it upside down.
Water the area well. Spread a four-inch layer of straw over the entire bed and water well again. The straw acts as a barrier against grass regrowth and it also adds valuable organic matter as it decomposes.
On top of the straw layer, place two yards, per 75 square feet, of good topsoil mix. Then add 40 pounds of steer manure, per 75 square feet. Rake this in, and wait two to four weeks to allow time for decomposition to begin. You then can begin planting. Transplants are recommended for the first year, as the soil temperature will raise slightly, making it difficult for some seeds to germinate. By the end of the growing season, the straw layer will be reduced to provide four inches of good loamy soil, with one to two inches of straw beneath.
Continue watering well during the growing season. This will maintain temperatures warm enough for decomposition. Soil microbes and bacterial will use nitrogen as protein to create nutrients during the composting process, so it's important, each year, to add extra sources of nitrogen. This could be pre-composted steer, chicken or sheep manure. You also can topdress the bed with grass clippings that are free of fertilizers or weed killers, and you can add leaves and other plant material. Do not introduce any weedy material into the garden, as the composting process will not be hot enough to destroy all weed seeds.
The increased depth of soil in this raised bed garden promotes better root development, preserves water and nutrients that otherwise would be lost through soil erosion and lowers the temperature of the soil during the summer, thus preventing evaporation. It also conserves valuable organic matter by slowing the decomposition of materials. This allows plants to absorb nutrients more efficiently throughout the growing season.
Photograph courtesy of Judy Sedbrook.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010