by Connie Oswald Stofko
When you have clay soil, should you add compost or sand?
“In the long run, by far, the best thing you could possibly add is organic matter,” said John Farfaglia, extension educator with Cornell Cooperative Extension in Niagara County. Organic matter can be compost, autumn leaves, peat moss or other plant material.
Organic matter is better because you have to add so much sand to loosen the clay, it’s not practical, Farfaglia said.
I asked this question because a reader left a comment on a previous article talking about the value of adding sand to clay soil. In a garden that is 16 by 45 feet, he said he added four tons of sand.
Another reason to use organic matter is that it improves your soil in ways that sand doesn’t, Farfaglia said. Organic matter gives your soil better texture and supports organisms such as earth worms and microorganisms that are beneficial to plants.
You can add organic matter to your soil at this time of year. Tip: If your garden is still wet, give it a few days to dry out. If you try to work with the soil when it’s wet, you can damage the soil structure. If you pick up soil in your hand and you can crumble it, you can work with it. If it sticks together, it’s too wet.
To break up the clay, try to incorporate your organic matter into the top few inches of your soil where the roots of your plant will be, he said. That will have a faster effect.
If you can’t do that, you can still top dress compost or organic matter on top of the soil. That will help.
You will need to add organic matter over a number of years, he noted.