I Need Help Amending My Clay Soils!

“We have added compost, mulch, and additional black dirt, but the soil continues to be very hard and difficult to grow vegetables in. What should we do?” Question from Linda of Schererville, Indiana

Answer: I looked at the soil map for your area, and your soils are indeed very clay-rich and silty. The trouble with clayey soils is that they lack aeration, good drainage, and become very hard when dry. This disables water percolation and the fine roots of vegetables from gathering necessary air and moisture for top performance. There are several things that you can do to improve poor soils like yours for better vegetable growing.

  1. Improve and uplift your amending strategy. For amendments to be effective in clay soils, they need to be evenly incorporated in quantity. They also need to be lifted above the soil level to maximize drainage. Add amendments, like compost and rich topsoil, into your soil at a ratio of two parts rich amendments to one part ground soil, and till them in until well incorporated. Then berm your soils to lift them above the soil level. (Click here to learn more about berming.) Do not amend your soil with bark mulch. Bark binds nitrogen, keeping this essential nutrient from growing plants. Finally, add a quality fertilizer for vegetable growing to ensure your plants are getting the nutrients they need.
  2. Double dig. You can maximize the rooting potential of your vegetables by double digging. This means digging a 1- to 2-foot deep trench below your vegetable plots and amending the backfill with the same two to one ratio of amendment to soil. Fill the trenches in with the enriched backfill, and then berm with more amended soil up top to ensure excellent drainage and deep root growth for your edibles. (Click here to learn more about double digging.)
  3. Try raised bed gardening. If you continue to have trouble with vegetable garden productivity, turn to raised bed gardening. This will allow you to give your plants the best soil possible for excellent vegetable production. We recommend adding Black Gold Garden Compost Blend and Black Gold Garden Soil to raised bed plantings.

I hope that you have better luck with your vegetable garden this year!

Happy gardening,

Jessie Keith

Black Gold Horticulturist


Plants are the lens Jessie views the world through because they’re all-sustaining. (“They feed, clothe, house and heal us. They produce the air we breathe and even make us smell pretty.”) She’s a garden writer and photographer with degrees in both horticulture and plant biology from Purdue and Michigan State Universities. Her degrees were bolstered by internships at Longwood Gardens and the American Horticultural Society. She has since worked for many horticultural institutions and companies and now manages communications for Sun Gro Horticulture, the parent company of Black Gold. Her joy is sharing all things green and lovely with her two daughters.

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