In her story “A Sanctuary in Every Season” (Fine Gardening #54), Pat Bullard mentions greensand as an ingredient in a mixture that will help break up clay soils. What is it, and how does it work?
John Owens, Glen Heal, FL
Nancy DuBrule, a garden designer in Northford, Connecticut, replies: Greensand is a naturally occurring, green mineral powder with the texture of fine sand. The most common type is mined in New Jersey and therefore called Jersey Greensand. It is primarily a source of potassium, but it also contains iron, magnesium, calcium, phosphorus, and up to 30 trace minerals that are necessary for plant health.
In organic gardening, a popular saying is “Feed the soil and the soil will feed the plants.” Feeding the soil actually means feeding the life in the soil. Greensand, which is not soluble in water, has valuable nutrients that are released to plants only after being digested by the microorganisms in soil. These microorganisms also break down organic material. The result is a rich, well-balanced, black-colored soil teeming with earthworms.
I have been using greensand in my landscape business for many years. At first many of my customers were puzzled because they had never heard of it, but the results speak for themselves. Gardens that have greensand added at the initial stages of soil preparation have plants that are much more vigorous, with strong stems and abundant blossoms.