How to Make Your Own Compost: A Beginner's Step-by-Step Guide

By James Harlow  |  February 2025  |  10 min read

Compost is often described as black gold by experienced gardeners, and with good reason. This dark, crumbly material, made from decomposed organic matter, is one of the most powerful tools available to the home grower. It improves soil structure, adds essential nutrients, supports beneficial microbial life, and helps retain moisture — all at once, and entirely for free if you make it yourself.

Despite its reputation among beginners as being complicated or smelly, composting is actually straightforward once you understand the basic principles. This guide will walk you through everything from choosing your composting method to troubleshooting common problems.

Why Compost Matters

Before getting into the how, it is worth understanding the why. Soil health is the single most important factor in determining how well your plants grow. Compost feeds the billions of bacteria, fungi, and other microorganisms that live in healthy soil, and these microorganisms in turn make nutrients available to plant roots in a form they can absorb. A single teaspoon of healthy, compost-enriched soil can contain more living organisms than there are people on Earth.

Choosing Your Composting Method

Open Pile or Bay System

The simplest approach is an open pile in a corner of your garden. Layer brown materials (dried leaves, cardboard, straw) and green materials (vegetable peelings, fresh grass clippings, coffee grounds) in approximately a 3:1 ratio of brown to green. Keep the pile moist but not waterlogged, and turn it periodically to introduce oxygen and accelerate decomposition. Open piles work well but can take 6 to 12 months to produce finished compost.

Enclosed Compost Bin

A lidded plastic compost bin is tidier, retains heat and moisture better, and is less attractive to rodents than an open pile. Most garden centers sell basic models at reasonable prices. The enclosed environment typically produces finished compost more quickly than an open pile, often within 4 to 6 months during warmer weather.

Hot Composting

For gardeners who want finished compost within 4 to 8 weeks, hot composting is the answer. This method involves building a large pile (at least 1 cubic metre) with the right blend of materials, turning it frequently (every 2 to 3 days), and maintaining optimal moisture. When done correctly, the core of the pile reaches temperatures of 55 to 65°C, which kills weed seeds and pathogens while dramatically accelerating decomposition.

What to Compost

Never compost cooked food, meat, dairy products, diseased plant material, or pet waste, as these can introduce pathogens, attract pests, or create unpleasant odours.

The Composting Process Step by Step

Step 1: Choose your location. A partially shaded spot with good drainage and access for turning is ideal. Avoid placing your bin directly against a fence or wall.

Step 2: Start with a layer of coarse brown material such as woody stalks or scrunched cardboard at the base. This creates drainage and airflow from the bottom of the pile.

Step 3: Add layers of green and brown materials alternately, aiming for roughly three parts brown to one part green by volume. Each layer should be 5 to 10cm deep.

Step 4: Keep the pile moist. It should feel like a damp sponge — wet enough to hold together when squeezed, but not so wet that water drips out. In dry weather, water occasionally. In wet weather, cover the pile.

Step 5: Turn the pile every few weeks to introduce oxygen. Use a garden fork to move material from the outside of the pile to the centre, where temperatures are highest.

Step 6: Harvest your finished compost. Finished compost is dark brown, crumbly, and smells earthy rather than rotten. If you see recognisable food scraps, the compost is not ready yet.

Troubleshooting Common Composting Problems

Pile smells bad: Usually caused by too much green material or insufficient aeration. Add more brown materials and turn the pile to introduce oxygen.

Pile is not heating up: The pile may be too small, too dry, or lacking in green nitrogen-rich materials. Add fresh grass clippings or vegetable scraps and water lightly.

Pile is attracting flies: Bury food scraps under a layer of brown material rather than leaving them on the surface. An enclosed bin will reduce fly problems significantly.

How to Use Finished Compost

Apply a 3 to 5cm layer of finished compost as a mulch around established plants, or work it into the top 15 to 20cm of soil before planting. For containers and raised beds, mix compost in at a ratio of roughly 25 to 30 percent of total volume. You can also make a liquid feed by steeping a cloth bag full of compost in water for 24 to 48 hours — the resulting tea is a gentle, all-round plant tonic.