We began stage two today. While Jim rototilled in the first layer of mushroom compost, I purchased the vermiculite and peat moss. From what I’ve read on the Square Foot Gardening forums, it seems that vermiculite is hard to find, so I was happy to get it from a local supplier, Terralink, on Riverside Road. I bought Sunshine Strong-lite Coarse, two 4-cubic-foot bales at $33 each, which will be one per 4′ x 20′ section. It is on the list of products acceptable for organic growing. This is a one-time addition to the garden as it does not get used up over time the way compost does.
Vermiculite is is a mineral that expands to many times its original volume when processed with heat. It is recommended to improve soil because it provides aeration and drainage; it holds large amounts of water which it then releases it as the soil dries out; it is sterile and disease-free, non-toxic and pH neutral. By the way, it is very light and dusty, so using a painter’s mask is smart. Spreading it on a windy day is not.