Sandy soils typically have a high permeability that will allow water to quickly drain from the site. In most cases, a soil that is too well drained will not hold enough moisture for good plant growth. You can add materials to the sandy soil for moisture holding capabilities. Sphagnum moss and some wood byproducts will slowly break down over the years to aid in retaining moisture. Before any soil building process is undertaken, a soil test must be completed and sent off to your local agricultural extension service.
Conduct a soil test and send that sample to the local agricultural extension service prior to working the sandy soil. The service will provide a detailed analysis of the soil, and may recommend a particular process that includes differing procedures. Not all sandy soils are the same, and may have different chemical make-ups.
Work the sandy soil up using a rototiller over the area. Before incorporating any organic material into the soil, it is best to loosen it as much as possible.
Add approximately 2 to 3 inches of sphagnum moss across the surface of the sandy soil area. Use the rototiller to work the material into the soil.
Spread 2 to 3 inches of wood chips or sawdust over the location. The more organic material rototilled into the sandy soil, the more moisture capacity it will have.
Plant the area with a winter cover crop to reduce erosion and improve the organic material in the soil. Seed rye grass in late September by broadcasting seed at a rate of 1 to 2 pounds per 1000 square feet. You can also add some red clover seed to the mix at an application rate of ¼ pound of seed per 1000 square feet.
Work the cover crop into the soil the following spring using the rototiller. The sandy soil will be ready to plant and should contain a high organic material consistency.
Take another soil test. Use the results to add any further amendments. Follow the extension service laboratory results.