Saturday, March 23, 2013

Soil Ecology

It's still too cold to start gardening in earnest, so why not kill the time by talking about gardening? I attended a lecture on soil ecology at Boston Natural Areas Network on March 12th, the finale to a series on composting.

Dr. Wendy Heiger-Bernays from Boston University started us off with a scientific look at lead testing. Many of us were surprised to hear that UMass Extension was underfunded for many years, leading to potentially incorrect results on lead content in soil samples. (If you have had your soil tested within the last year and a half, don't worry, you're fine. If not, you might want to re-test.) The testing facilities are back in shape now, and in the future, they may have the capability to test compost in addition to soil.

The second speaker, Casey Townsend, talked to us about soil ecology systems. He runs the rooftop garden on the Boston Medical Center parking garage, called the Northampton Square Rooftop Garden.

I don't know about you, but I often think of gardening as a linear process. Start with compost, sow seeds, water and weed, harvest. Each year I start over. Casey thinks a bit deeper about gardening, looking at the soil as a positive feedback loop between three aspects: organic matter, native populations, and nutrient build-up. Build on one aspect, and you build the rest too.

So what is organic matter? Compost, of course, is a fast boost for your soil. A slower (but very efficient) option is organic mulch, like hay, which will retain moisture in the soil and can be tilled under in the fall. Casey recommended we look at the methods used on Arnolds' Pleasant Valley Farm as a model.

The Arnolds mulch with a thick layer of saltwater marsh hay through the growing season. In the fall, they till it under. And by spring, it's gone! Their soil is so rich with native populations that the hay just disintegrates, returning nutrients to the soil.

Speaking of native populations - if you have earthworms, your soil is in good shape. If not, adding compost and mulch can encourage earthworms to move in. You can also supplement your garden with populations of nematodes and parasitic wasps, which like to feed on the pests in your garden. These can be purchased from gardening centers or online.

The third aspect of your soil is nutrient build-up. Decaying organic matter can add minerals like boron and magnesium. Casey hopes that his garden will eventually build up nitrogen, potassium, and phosphorus, minimizing his input of fertilizer.

This explanation of soil ecology only piqued my interest to learn more - I asked Casey for some book recommendations on soil ecology systems and he recommended these:

BNAN has many more awesome workshops coming up this spring and summer, and they're all FREE. Some I plan to attend are:

Saturday, March 30, 11am-5pm
38th Annual Gardeners Gathering: a full day of gardening skill-shares, talks and demos.
(115 and 120 Forsyth Street in Boston)

Saturday, June 15, 9-11am
Little City Gardens
(30 Edgewater Drive in Mattapan)

Saturday, August 10, 9-11am
The Secrets of Seed
(30 Edgewater Drive in Mattapan)

May to July
Global Gardeners: Conversations and demonstrations with expert growers from Myanmar, Iran, and Somalia, who have transplanted their traditional farming methods to New England. They will share their gardening methods, as well as their stories of how they arrived in Boston.
See for more details.

What inspires you as you  look forward to spring?

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