Trench Composting – How To Guide

Trench composting is a gardening method commonly used by individuals who have gardens arranged in rows. If your garden is arranged differently, such as in 1 x 1 foot squares (otherwise known as square foot gardening), you may adjust this system to fit your setup. However, since this method is typically used for vegetable gardens, we advise against using it to compost pet feces.


To practice trench composting, you first dig a trench and add the materials you want to compost, following the list what you can compost. Next, cover the trench with soil and allow natural decomposition to occur.

Rotation of Rows

Your yard will consists of three rows, labeled as #1, #2, and #3, that are rotated in a three-year cycle. This means that once the third year is completed, the cycle starts over again from year 1.

Year One

During the initial year, a trench is excavated in Row #1 to accumulate compost throughout the year. Row #2 is designated for crop cultivation, while Row #3 is utilized as a pathway for easy access to the plants.

Composting items – Crops – Path

Year Two

In the second year, crops are grown in row #1 which benefits from the nutrients of the compost deposited in the trench during the first year. Row #2, where the crops were grown in the previous year, is left unplanted and used as a pathway to avoid soil depletion. A trench is dug in the compacted soil of row #3 to serve as the compost deposit area for the second year.

Crops – Path – Composting Items

Year Three

During the third year, the crops are planted in row #3, which benefits from the compost deposited during year 2. Row #1 is used as a walking path as the soil is depleted from the previous year’s harvest and needs time to recover. A trench is dug in the compacted path of row #2 to deposit compost for year 3.


Benefits Of Trench Composting

There are many benefits to trench composting, which include:

  1. Low-cost way to enrich the soil: Trench composting is a low-cost method of enriching the soil. It requires no special equipment, just a shovel or garden fork to dig the trench.
  2. Low maintenance: Unlike traditional composting methods, trench composting requires no turning. This makes it a low maintenance option for busy gardeners.
  3. No dedicated composter space needed: With trench composting, there is no need for a dedicated composter. This is particularly beneficial for gardeners with limited space.
  4. No need to transport finished compost: Since the compost materials are buried directly into the soil, there is no need to transport finished compost to the garden site.
  5. Worms feed off the waste and enrich the soil: Trench composting provides a habitat for earthworms, which feed off the compost materials and enrich the soil with their castings.
  6. Keeps compost materials warm and moist: Burying compost materials in a trench helps to keep them warmer in cool months and moister in dry summer months, which promotes faster decomposition.
  7. Neat “out of sight” method: Trench composting is a neat and tidy method of composting. Since the compost materials are buried in the ground, there is no unsightly compost pile to contend with.

Of course, the end result of trench composting has all the benefits of traditional composting. It produces a helpful soil amendment that improves plant health and fertility.

Trench Composting Disadvantages

While trench composting offers many benefits, there are some drawbacks that should be taken into consideration.

  1. Slower Decomposition: The anaerobic nature of trench composting makes it slower to decompose compared to quicker aerobic methods.
  2. Pathogens: Immature compost can contain pathogens that may transfer to food crops, posing a health risk.
  3. Organic Acids: The anaerobic process releases organic acids that can harm plants, affecting their growth and health.
  4. Lower Nutrient Content: The end result of trench composting is less nutrient-rich compared to aerobic compost.
  5. Pests: Compost materials need covering immediately to avoid attracting pests such as rodents and insects.
  6. Waiting Period: It is generally recommended to wait one year or the following year’s growing season before planting into compost trenches. Planting sooner involves certain risks.

It is important to consider these drawbacks before deciding whether trench composting is the right method for your gardening needs.