Compost pile and worm bin perfect homes for kitchen scraps

Posted April 01, 2010, at 6:15 p.m.

In our new course at Shead High School, Growing and Eating Real Food, 18 students are laboring two hours every day to build the Eastport Schoolyard Garden, transforming tiers of hefty hemlock timbers into raised beds, growing broccoli and chard seedlings under lights in the classroom, crafting letterhead for the new garden and letters of thanks to the community supporters who made it all possible.

In the second week of class, the students started a compost pile in the garden and a worm bin in the classroom. Now I find bags of vegetable scraps on my desk every morning, fodder for the worms or the pile, and every afternoon the students take the temperature of the compost pile and the worm bin.

Things are heating up. A group of four students, the Wigglers, divided the worm bin (made from a 16-gallon tub) into nine equal sections. Each day, they bury exactly 57 grams of veggie scraps under the bedding of the next consecutive section and then take the temperature of each section. Already, in the second week of this experiment, they are seeing differences in section temperatures that reflect the metabolism of decomposers and earthworms hard at work. Banana peels fed to the worms on Monday are gone by Friday.

The compost pile’s temperature is rising to spite the cold rains, a result of adding two 5-gallon pails of llama poop plus a 30-gallon trash can of chicken manure to the pile on set-up day, just a week ago. The nitrogen-rich manures were mixed with a bale of straw, two large bags of seaweed, two bags of last fall’s leaves, and a few days’ accumulation of vegetable scraps from the school cafeteria.

My students are learning the most important lessons that gardening can teach: how to build healthy soil to grow healthy plants; that gardens, compost piles, and worm bins are bastions of biodiversity; that throwing veggie scraps into the trash can is a sin.

Amending the soil with compost on an annual basis is the heart of successful gardening and one of the best ways to do this is to mulch the garden, both the vegetable beds and the ornamental plantings, with compost. Not chunky bark, but compost.

When it comes to building healthy soil, bark mulch is a poor substitute for finished compost. Chunks or shreds of bark take a long time to decompose, and the bacteria working to break them down will actually consume available nitrogen as they work, leaving less nitrogen for plant growth. A good rule to follow in choosing a mulch would be: If you can still recognize the raw material in the mulch, don’t use it.

Make your own compost, or buy finished compost in bulk or bags. Spread it on the surface of the soil, around and between plants an inch or more deep, taking care not to pile it up against the plants themselves. Watch it quickly disappear within a single season, feeding the earthworms, improving water-holding capacity and pore space of the soil. Do it again next year and every year.

Now may be a good time to make the switch from bark mulch to compost mulch. Government subsidies to support biomass energy crops could limit bark mulch supply and increase prices. Compost, the better mulch, may become the better bargain, as well.

We cannot meet the mulch demands of Marjorie’s Garden with our home-made compost, and so we make several trips each spring to Seal Cove Farm in Lamoine for truckloads of composted goat manure — nannyberries — and we get to scratch the goats behind the ears in the bargain.

Find your local source of stable litter or farm animal manure. If it is not fully composted by the farmer, add it to your garden’s compost pile, mixing it with shredded leaves, straw, seaweed, garden waste, vegetable scraps from the kitchen, and worm castings from your home worm bin. Turn this pile whenever it cools off, and watch it shrink to several wheelbarrow loads of a dark, crumbly mulch.

Spread the word: compost is better than bark.

Send queries to Gardening Questions, P.O. Box 418, Ellsworth 04605, or to rmanley@shead.org. Include name, address and telephone number.

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