Make Your own Compost

Feed the Soil, Not the Plant

by: Aidan Feeney

Learning to create quality compost is one of the most important fundamental skills of any gardener. Too often, growers overlook soil health and instead focus on bottled or bagged fertilizers. Fertilizers are effective in their own right, but they do not contribute to the basis of a healthy soil, which lies in its biology.

Compost, on the other hand, introduces and feeds populations of organisms in your soil. These organisms break down organic matter and minerals, making them available to your crops. The result is crops that are more vigorous, healthy and nutritious than anything that can be grown using fertilizers alone. This is what is meant by the old farming adage “feed the soil, not the plant.”

Compost Ingredients

When assessing what should be put into your compost pile, they should be categorized as “brown” or “green” ingredients.

“Green” ingredients include the fresh, moist waste items from the garden and back yard. Examples include grass clippings, kitchen waste, garden waste, green leaves, etc. These ingredients are typically produced by most households in abundance.

“Brown” ingredients, on the other hand, can be harder to come by without seeking them out. “Brown” ingredients include straw, dry grass, dry leaves, sunflower stalks, dry reeds, corn cobs, etc.

When building a compost pile, it can be helpful to think of it as if you are building a fire. The green ingredients are the flames. They are fast to decompose and heat up, but on their own they burn out quickly and decomposition will stop. The brown ingredients are the wood for the fire. They keep the flames burning, as well as provide structure for the pile to allow for air flow, which is critical for proper composting.

I recommend that beginners start by using straw for brown material. Straw, with its lofty structure and hollow stems, ensures good air flow throughout the pile. Most of the time when beginners fail, it is because their compost heap collapses on itself and becomes anaerobic. This can cause foul odors and incomplete decomposition.

Building Your Compost Heap

You should build your compost site close to the garden. Pick a location where it will be easy to bring the ingredients from the kitchen and garden, but also easy to bring the finished compost to the garden. I recommend using some type of bin or structure to contain your heap. There are many compost bins available for sale, ranging from wooden containers with lids to barrel-shaped tumblers that can turn the pile with a hand crank.

Whatever you choose, it is best to get two bins, one for actively composting and the other for curing or aging a pile. The bin should be at least 36 inches square. The larger the heap, the more likely you are to be successful in keeping it hot and biologically active.

When starting your heap, start by layering three inches of straw at the base layer. On top of the straw you can add one to six inches of green material. Add one inch if all of the material is dense and wet, like grass clippings, poultry litter or food scraps. Add up to six inches if the green material is loose and lofty, like tomato stems, broccoli stems, etc. On top of your green material, you should add half an inch of native soil. This can be done by adding weeds or plants with soil on their roots, or simply by covering the pile with a thin layer of topsoil.

This soil acts as the spark that will light the microbial fire in your compost pile. The soil is already teeming with microorganisms. By introducing them into your pile, you are inoculating the pile and providing conditions for them to thrive. Next, add another layer of straw and then repeat the other steps with green material and a layer of soil.

To start a new heap, you should build at least three layers of each ingredient type at once to get the pile heating up. Once the pile is hot, you can add single layers at a time, as you produce ingredients. Continue to layer on ingredients until the pile is three feet high.

When actively decomposing, the pile should reach temperatures between 120-160 F. Once it cools down, this is your cue to flip the pile. Using a pitchfork, move the heap to your second bin. This action of remixing and moving the pile will likely cause it to heat up once again to break down the ingredients even further. Once in the second bin, I like to cover the heap with either a lid or a tarp. I’ll water it occasionally if it seems too dry, but it is best to keep the rain off your compost to prevent nutrients from leaching out.

The two most common symptoms of a poorly-composting heap are either failure to heat up or foul smells. If the heap remains cold, the problem is likely that you have too much brown material and not enough green. This is like trying to start a fire with a big round log and a few sparks. Your need more tinder and flame to light the log.

Foul odors, on the other hand, are symptomatic of too much green material and poor airflow. This happens when you add materials like grass clippings too thickly. The clippings will heat up quickly, but then collapse on themselves and become anaerobic. To remedy this, mix the pile more thoroughly with straw.

Once you get started, you will discover that composting is not overly complicated. Start with using straw, but as you gain experience you can experiment with other ingredients. By composting, we are simply facilitating the natural processes that have created all the soil nutrients on Earth. Each year, our gardens give us so much. If the soil is neglected, though, yields and quality will drop and every aspect of growing will become more difficult. Composting is our way to close the loop, give back to the soil and continue harvesting for years to come. ///

Aidan Feeney is the owner of Fog Town Farm on Nantucket and a regular contributor to Nantucket Today.