How to Compost

How to Compost

First, what exactly is compost? Compost is a mix of yard and garden debris, kitchen scraps, and other organic materials that are broken down by bacteria and other microorganisms into a nutrient-rich, dark, crumbly material, called humus. (No, not the chickpea kind of hummus.) Here's a basic composting primer.

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Since composting is all about breaking down organic matter there’s very little you can do wrong with your compost bin -- these tips are to help the process go faster. The speed of composting depends on moisture, oxygen content, temperature, and the right mix of ingredients.

Ingredients

Roughly 75 percent of what goes into your compost pile should be carbon-rich brown material (dried grass, leaves, shredded newspaper, etc.) and about 25 percent should be nitrogen-rich kitchen scraps like veggie and fruit peels. (We’re not actually talking color here -- it’s just a way to tell the two types of compost material apart.) The mix is important because the microbes that break down your compost need a variety of different food sources.

Moisture

A compost pile should be damp, but not wet -- kind of like a sponge you just squeezed out. Your bin should allow for easy drainage: Sitting water suffocates the good kind of bacteria and is an invitation for pests like mosquitoes and raccoons. Water trickling through your pile can also wash away valuable heat and nutrients. But if there’s not enough water, the organic materials won’t break down well. If your area is arid, keep an especially careful eye on the bin during the summer. You can always add water with a hose if it’s too dry or take the lid off on a sunny day if it’s too wet. In other words, the key here is balance.

Oxygen content

Oxygen is important for the bacteria that break down your organic matter into compost. Keep your compost aerated, which means there’s oxygen flowing through it, either by purchasing a composting bin that’s self-aerating or by using a pitchfork or similar tool to turn the compost yourself. Aerating is important because it fuels the aerobic microbes that help break down your trash more quickly. It also keeps the smelliness to a minimum.

Temperature

Warmth is good for composting. Between 140 and 160°F makes for the fastest composting, but as long as you keep the temperature above freezing there will be some composting action. The microbes in your pile generate their own heat, so your job is to keep the pile insulated. And, since compost is self-insulating, just make sure it sits in the sun and away from the wind. A compost bin with dark walls or a black tarp placed over the pile will also help keep the temperature up.

Now find out how you know what time of year to plant a garden.

-- Paula Kashtan