Gardening and Horticulture - Treat Clay Soil

What can I do to treat clay in my soil? Having a hard time getting things to grow well.

Thanks for any help.

Joe

You need organic material and lots of it. You won't fix the problem overnight, but in time it will get better.

Compost or some other organic material.

add clean sand, peat moss, compost and pearlite if it's a small area . till in as deep as possible. drainage will be improved only as deep as you till. Faffard makes an organic soil conditioner as i'm sure others do.

A soil test will tell you what amendments need to be made to your soil. Your local Dept. of Agriculture Extension Agent can provide you with info on soil tests, amending soil, and composting.

I live in the hills around San Jose and I swear you could almost remove a shovel full of clay and throw it on a turntable and make a pot. I can't imagine a better source for clay.

I have had success adding compost. I found that at about 50% the soil will support any plant. The problem is that for anything beyond small annuals you need deeper conditioning. Then the problem was for me that if I dig a deep hole to support a large plant (ie. Camelia, Rhodedendron, Peony etc.) it will fill with water during hard rain or accidental overwatering and suffocate the plant. If I dig a test hole and put water in it, it will basically stay there forever if evaporation is slow.

So in the end, I decided to put in a raised bed. My bed is a 4' border backed by a fence. I screwed pressure treated 2x12's to the fence so I would not damage/rot the fence and used tumbled concrete retaining wall blocks for the front of the bed. I then had 6 yards of planting soil delivered and filled it up. It's a ton of work but for me it would be a tightrope to get any of the above plants to thrive and one overwatering mistake or heavy rain could do them in.

If you don't care what the plants look like there are plants that will thrive in the worst clay soils. When I moved in there were several 10' bushes planted that had to be heavily pruned once a year and the roots were all over the yard. However, they did not flower and they are not particularly attractive. I have no idea what kind of plants they are but I'm sure the local nursery knows plants that will grow well in your native soils if you decide to go that route.

Do not add sand. That is a common misconception.

Sand will just make the clay soil even harder.