Ask Burton: Q: My clay has terrible drainage! Should I add sand to the soil to loosen it?

A: No!
Sand drains far better than clay does, so it seems reasonable to say, “Hey, this material is looser than my normal soil. Wouldn’t it loosen what I have in the flowerbeds?”

Unfortunately, it doesn’t work that way. Sand is a larger soil particle size than clay, and it does drain better by itself. But small amounts of sand mixed into clay will merely increase the drainage problems of clay as the tiny clay particles aggregate with the sand and form a packed, concrete-like material. It would take many tons of sand replacing a majority of the clay to drain properly in a typical flowerbed.

Now, expanded shale that is in our soil builder is a far larger particle size than sand so those drainage problems won’t occur, and is porous enough to increase soil aeration even when soils are waterlogged. Compost is highly beneficial as well, both for drainage and soil nutrition.

We recommend our Covington’s Soil Builder that has expanded shale cotton burr compost and green sand.  You’ll get the results you were looking for.

  • Remember: Mix 1/2 Covington’s soil builder with 1/2 native soil when amending your soil for best results!