By Glenn DiNella
In the plant world soil is one of the big three in the trifecta of building blocks for success (along with sunlight and water). If any of these three is out of whack, you are doomed to failure. Today we’ll deal with soil.
In the Southeast, after digging through an inch or two of good, loamy topsoil, most of us strike clay (typically red clay). If you are closer to the coast, you probably hit sand. Either way the best thing to do is till in loads of organic matter. Soil conditioner, manure, and mushroom compost are readily available and great for improving soil fertility and structure.
Some soil mixes contain sand and partially composted pine bark or hardwood fragments (called fines). Other mixes add fly ash as a fertilizer, but those mixes also could contain heavy metals, so you might want to avoid these in your veggie garden.
Coarse “builder’s sand” or “paver sand” (not fine play sand, which compacts) also improves drainage in clay soils. But you have to incorporate this in large amounts—at least 50 percent of the total soil volume, which is not practical in large beds. Adding small amounts of sand to clay soil only creates something more akin to cement than soil.
When it comes to filling dips and holes in your lawn, don’t use sand—use topsoil or even composted cow manure. If you fill holes with sand in your clay- or loam-based lawn, you create small spots that dry out more quickly than surrounding areas, and you might get dead spots when a summer drought strikes.
(By the way, the sand myth sprang from golfers who saw golf course grounds crews top-dressing their putting greens with sand. The key difference is typically golf greens are created on soils that are almost pure sand.)
I like to stop at my local Starbucks and grab the “Grounds for Your Garden” from a bucket near the door. I wish more people would take advantage of this as a soil amendment. Some coffee shops just throw away their grounds because nobody takes them.
Grounds can be slightly acidic, but a dash of lime counteracts this. Soils in the Southeast are typically slightly acidic, so an annual lime application may be in order for your lawn. Only a soil sample can say for sure.
Last bit of advice: Get a soil-test kit from Lowe’s. This will help you determine the pH and fertility of your soil so you have a better idea how to improve it.