Hot topic: Cooking up compost



It’s often said that making compost is like cooking. You assemble your ingredients — in this case, a combination of dry, high-carbon organic materials such as dead bean vines and straw, mixed with moist, high-nitrogen ones such as kitchen scraps and manure. Then you use heat to break the ingredients down. With cooking you use the stove. But compost, thanks to aerobic bacteria that show up to help, makes its own heat.

Given enough time, any well-built compost pile — not too wet and not too dry — will wind up as “black gold” that will fertilize and give good structure to your garden’s soil. If you’re curious, stick one of those long-stemmed compost thermometers into the pile’s center, and as long as it heats to between 120 and 150 degrees for a decent period, the compost will mature, like a slow-simmering stew. This might take a year or more.

If you’re in a hurry, you’ll need to turn the pile so that the cool outer parts change places with the hot center and get a chance to bake. This can be done by redistributing the materials into an adjacent container, or just by shoveling or forking them into two separate piles on the ground and putting them back again in reverse position, with the least decomposed stuff in the middle.

Your cue to turn the compost is the inner temperature, revealed either by said thermometer or by boldly plunging in your hand. When the center heat has reached its maximum and then starts to cool, it’s time to turn.

In addition to folding the outsides in, you’re also introducing air into the mix, which keeps those aerobic bacteria on the job.

According to J.I. Rodale’s “How to Grow Fruits and Vegetables by the Organic Method,” published in 1961 and still my gardening bible, you can make finished compost in 14 days. This method relies on an extra dose of high-nitrogen amendments such as bloodmeal, zealous shredding and a regime that has you turning the heap three times — on the fourth day, the seventh day and the 10th.

This is extreme composting at its best, but I admit that my own composting history has been of the Crock-Pot school, with two or three successive heaps taking their own sweet time.

This year my husband and I are trying something new in our home garden. We’ve lined and topped our pile of half-finished compost (held together with panels of lobster trap mesh ) with black sheeting that will let in air and vapor but exclude heavy rain, and help keep even the outside of the heap warm and moist.

There’s a product called Compostex that is specifically designed for this purpose. But because it is pricier than regular black landscape fabric at our local home improvement store, we’re going to give the latter a try.

We’re not only lazy, we’re also cheap. But come spring we’re hoping to have some fine rations for the garden.

Barbara Damrosch

Barbara Damrosch

Barbara Damrosch’s latest book is “The Four Season Gardener’s Cookbook.”
Barbara Damrosch

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