Clay Soil Preparation - Knowledgebase Question

Name: Lonnie Brundage
Long Beach, CA
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Question by lonsgrdn
October 29, 1997
I have a garden space that has not been used in 15 or so years. The soil analysis says its clay. Please give some direction on soil preparation. Should I use green sand or not?

Answer from NGA
October 29, 1997
Greensand provides sandy mineral content that can improve drainage in clay soils, and it also contains a lot of potassium that is slowly released over time. If your soil test results suggest that you need to boost potassium in the soil, you can add it asyour test recommends. It takes a lot of sand to really make a difference in the texture of a clay soil - a better method is to add organic matter.

The first rule in working clay soil is to stay out of it while it's wet, or it will set up likecement when it dries (think pottery!). As organic amendments decay, they release substances that improve soil structure, drainage and fertility. Start by loosening the soil and adding well- rotted manure, compost, chopped leaves, grass clippings, etc. Introduce some earthworms to the area, and start a compost pile with the materials mentioned above. As you garden, continue to add organic matter in the form of mulch, compost, seaweed-based fertilizers, etc. If you don't want to wait a long time for results, loosen the clay and spray it with seaweed-based fertilizer, and build a raised bed with good topsoil over the clay.

For great free bulletins on composting and soil improvement, contact Gardener's Supply Co. (;
ph# 800/863-1700) Hope this helps!

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