Miles wrote this article with Peter D’Auria. Originally published in the Spring 2015 issue of YES! Magazine, and online at http://www.yesmagazine.org/issues/together-with-earth/5-ways-to-get-your-soil-ready-this-spring
The key to gardening is dirt. If you can grow good dirt now, you can grow good vegetables this spring. And you don’t have to run to the garden store to load up on boxes and bags of stuff to do it if you start early and think of it as a year-round project.
Hugelkültür (mound or hill culture) is a long-term method of soil improvement that makes use of wood debris. Bury excess wood (twigs, branches, lumber scraps) a foot beneath the soil and cover with dirt and mulch. At first, the decomposition of the buried wood will eat up a lot of nitrogen, and the soil may need more water than usual. After about a year, though, the bed will be rich with nutrients, moisture, and beneficial organisms—perfect for gardening.
Lasagna compost, or sheet mulching, combines the benefits of compost with the simplicity of mulching. Spread compostable materials onto your garden beds in alternating layers of “green” material (table scraps, manure, grass clippings, vegetable waste) and “brown” material (wood, sawdust, leaves, straw, cornstalks, paper, cardboard). This will immediately cut down on weed growth in your garden, and as the lasagna compost decomposes over the next few months, it will aid in water retention, add nutrients, and create a healthy habitat for beneficial soil organisms.
Charcoal is one of the best soil amendments you can have. It is created by burning organic material in a low-oxygen environment. The process burns away excess gases, leaving behind a material that’s rich in carbon. Biochar differs from standard charcoal only in its application as a soil improvement. It was a key ingredient in the enduringly fertile “terra preta” maintained by indigenous Amazon River communities. What’s more, biochar can actually help alleviate the effects of climate change on a small scale by turning your soil into a carbon sink. There are several methods out there for creating biochar in your backyard, some more complex than others. All of them carry the benefit of knowing where your charcoal was made, and from what.
Most modern home gardeners enrich their soil through the addition of compost, mulch, and fertilizer. But there are several under-the-radar amendments lying around the house that can be used to quickly and easily improve your soil. Coffee grounds help acidify soil with a high pH, while eggshells add calcium and help correct acidic soil. Seafood might not immediately spring to mind when thinking about compost, but adding shrimp, lobster, and crab shells promotes microorganism growth, and seaweed is an excellent mulch that adds nutrients and repels garden pests. And a 2009 Finnish study found that diluted urine, followed by the application of wood ash, can be as good a fertilizer as anything on the market, adding nitrogen, magnesium, and other vital nutrients to soil with no increased risk of disease.
Crop rotation isn’t just for farmers. Even in your garden, switching up what you plant each season reduces nutrient depletion and prevents disease, pests, and weeds. Professional market gardener Eliot Coleman suggests a simple and effective eight-crop rotation scheme: potatoes, corn, cabbage, peas, tomatoes, beans, root vegetables, squash, and back to potatoes. For more flexibility, alternate plants that need a lot of compost and fertilizer (celery, melons, tomatoes, corn, peppers, cucumbers, pumpkins, eggplant, and squash) with plants that need little or no compost or fertilizer (carrots, onions, garlic, radishes, leeks, and turnips).