Q: How much worm castings should I use? My garden soil always ends up returning to Georgia red clay. I want it to eventually become good planting soil.

A: Worm castings are a great addition to soil but they don’t do much to help the soil drain quickly or stay soft. The tiny particles of worm excrement are comparable in size to clay and humus particles. Consider adding an inorganic component such as gritty sand (granite dust) or expanded shale (Soil Perfector, PermaTill, etc). Spread an inch of either material over your garden and mix it eight inches deep. I sometimes mix pine mini-nuggets into soil to help keep it loose.