Hearty Plants Start with Crazy-Rich Soil

A healthy soil is the basis of everything in the landscape and garden. There’s no need for petroleum-based fertilizers and pesticides when your landscape is rooted in fertile ground.

I am often asked what to add to or spray on plants to encourage growth or discourage pests. And my answer is always the same: Start with healthy soil.

A healthy soil is the basis of everything in the landscape and garden. It creates robust plants that can resist pests and efficiently use the fertilizers that nature provides. Frequent applications of petroleum-based fertilizers and pesticides are unnecessary when your landscape is rooted in fertile ground.

So what exactly is healthy soil? It actually starts with an ideal soil mixture of 50 percent mineral solids (sand, silt or clay), 22 percent air, 22 percent water and 4 percent to 6 percent organic matter (compost, organisms). The components may vary slightly, but this is an ideal soil.

To take the soil from ideal to healthy, it must also have minimum compaction — what biologists like to call low bulk density — and be absolutely teaming with soil life — the microorganisms and macroorganisms living within the soil.

The fastest way to minimize compaction is to core aerate every year and add ¼ to ½ inch of compost. Or, the slower but simpler way is to add the same amount of compost twice a year over a four- to five-year period. Do not add sand. If the soil is heavy clay, then incorporate into the soil half to 1 inch of expanded shale. Repeat as necessary.

To encourage all those wonderful micro and macroorganisms, incorporate directly to the soil copious amounts of compost and biochar. Compost supplies the building blocks of essential nutrients and carbon, while biochar houses all the nutrients and organisms.

And now for the secret sauce… Malcolm Beck, the late godfather of organic gardening in Texas, discovered a massive surge of organisms in his composting piles after adding Coca-Cola syrup. He realized the simple sugars in the syrup, aka simple carbon chains, benefited and increased the physiological activity of the microorganisms. Research has since proven him correct.

So add simple sugars like molasses, juices or soda to your garden and landscape to increase the health of your soil. The microorganisms will rapidly feed and reproduce on those simple carbon chains and encourage the other organisms to feed and return the nutrients to a form available to plants.

Picture of Mark Peterson
Mark Peterson
Mark A. Peterson was a conservation project coordinator for San Antonio Water System before retiring. With over 30 years of experience as an urban forester and arborist, Mark is probably the only person you know who actually prunes trees for fun. When not expounding on the benefits of trees and limited lawns, you're likely to find him hiking San Antonio's wilderness parks or expounding on the virtues of geography and history to his friends.
Dig Deeper

Find expert advice on garden basics, landscape design, watering and year-round maintenance.