The Secret to Healthy Soil
IT MIGHT SURPRISE YOU that no really good definition of healthy soil exists. You can’t send your sample to a lab and get a “soil health number.” Labs can measure soil fertility, which is a measure of nutrients in soil, but that’s only part of the story. Descriptions of healthy soil tend to be vague and say something like, “Healthy soil sustains life, maintains environmental quality, and enhances plant and animal health,” but that doesn’t help a gardener much.
I’m going to take a pragmatic approach to this topic and define “healthy soil” as soil having good structure with enough air, water, and nutrients to make your plants grow well. Plants obviously use the water and nutrients to grow, but it might surprise you to learn that plant roots also breathe in oxygen, which they get from the air in soil. In fact, soil will ideally be about 25 percent air.
What is soil structure? I recommend every gardener go for a walk in an established, wooded area and grab some soil. It’ll be black, and very crumbly. You won’t even need a shovel to dig up a handful of good soil. This “black
