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Why You Should Compost in Trenches

Hint: Because It's Easy!


A filled trench, ready to be covered with soil.

A filled trench, ready to be covered with soil.

Colleen Vanderlinden

What if there were a way you could compost your kitchen and garden waste, including weeds, that required almost no work on your part and enriched your soil in as little as one month? What if this compost pile were completely invisible, completely undetectable by smell, and could fit in just about anywhere in your garden? And, what if it required no turning whatsoever?

Welcome to trench composting.

What is Trench Composting?

Trench composting is very simple. You dig a trench (we're using the word “trench” loosely here; it doesn't matter what shape your hole is) approximately twelve inches deep, add roughly four to six inches of compostable materials, such as kitchen scraps, spent garden plants, prunings, thinnings, and weeds, and bury it with the soil you dug out of the trench.

The next step is.....well, there is no next step.

Why Would I Want to Compost in Trenches?

Maybe the best reason to compost in trenches is that it makes composting so simple. You don't have to worry about maintaining adequate moisture levels, or aerating, or sifting the way you do with a compost pile. But here are a few more reasons to give trench composting a try:

  • It gives plants nutrition right where they need it: at the root zone. Plant roots will make their way down deeper into the soil in search of the nutrition that you have buried there. So, the plant will be healthier in two ways: it will be nourished from the organic matter in the trench and it will develop a deeper, stronger root system. This means the plant will be better able to cope with dry conditions and heat, and will require less babying from the gardener.
  • It is invisible and will not produce odors. One of the issues many people have with composting is trying to figure out where in the garden to put a compost pile. While there are plenty of small-space composting solutions, trench composting completely eliminates this issue because you can bury waste anywhere you have an open bit of space in your garden. And, because it's buried under several inches of soil, even the smelliest kitchen waste won't be an issue.
  • It's a way to compost even if you're not “allowed” to compost. Many municipalities and developments have rules against home composting; this is a great way to do it on the sly.

Different Ways to Compost in Trenches

You can be as organized or free-form with your trench composting as you'd like. There are three general methods to use in your garden. All three work very well, and work on the premise that you don't want to plant directly on top of composing materials because the area will sink quite a bit while it breaks down.

  • Trench Rotation

    This is a method of incorporating organic matter into a garden a bit at a time while maintaining active growing and path areas. The general ideas is that you divide your garden into three zones: a trench composting zone, a pathway zone, and a growing zone. Each year, you move the trench compost to a different part of the garden, and shift the paths and growing areas as needed. By the end of three years, you've got compost under every part of your garden bed, and you can start the rotation over again. If you like things very orderly, this is probably the method for you.

  • Trenching Between Rows

    This works in any vegetable or annual garden in which you would plant in fairly regularly-spaced rows. Basically, plant your crops as usual. In the space between the rows, dig a trench to toss your compostables into. Fill the trench as you add materials, and it will break down and nourish the plants nearby.

  • ”Dig & Drop”

    This is the easiest way to do trench composting, and works even in perennial gardens and shrub borders. Say you've collected a large bowl of vegetable and fruit peelings. Simply take it into the garden, dig a 12” deep hole wherever you can find a spot, dump the kitchen waste in, and cover it over. It's fast, it's easy, and it requires very little digging.

So, try digging a trench next time you have a load of materials to compost. It will be the easiest compost you've ever made.

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