Making Cedar Compost Bins for Garden Waste

Why Cedar Suits the Working Garden

Cedar is a traditional choice for garden joinery, and for good reason. Its natural oils make it resistant to rot and insect attack, so it stands up to the damp, microbial world of a compost heap far longer than untreated softwood. That means fewer repairs and no need for chemical preservatives, which is reassuring when you plan to spread the finished compost around fruit trees and soft fruit bushes.

Cedar also looks the part. A well-made bin of horizontal slats settles into an orchard or kitchen garden without the brashness of plastic. More importantly, those slats are not just decorative. The gaps between them let air move through the heap, which is what separates slow, smelly rotting from proper aerobic composting. A cedar bin can breathe while still having a tight-fitting lid and a mesh base to keep rats, mice and foxes out.

Choosing the Right Spot

Put your bin where you will actually use it. Ideally, it sits on level, well-drained ground within easy barrow distance of both the kitchen door and the orchard. A spot that gets some sun is useful because warmth speeds up decomposition, but partial shade is fine in hot summers. Avoid low corners where water collects, and keep the bin away from the trunks of young trees so you do not smother roots or create a damp pocket.

If you have room, plan for two or three bays side by side. One bay takes fresh material, one turns and matures, and one holds finished compost. Even a single bin works well if you are prepared to empty it and start again. Leave enough space in front to swing a fork and to lift the lid clear.

Building the Bin: Slats, Spacing and Structure

A practical size is one cubic metre: about 100cm wide, 100cm deep and 100cm high. Smaller heaps struggle to hold heat; larger ones become hard to turn. Set four corner posts of 75mm x 75mm cedar into the ground or bolt them to a base frame. If you are building on soil, line the floor with a sturdy galvanised mesh to deter rodents while letting worms and drainage through.

• Use cedar slats roughly 100mm deep and 25mm thick.
• Leave 20–25mm gaps between slats for airflow.
• Fix slats with stainless steel screws or galvanised nails to avoid rust stains.
• Make a removable front section or a hinged side so you can fork out compost easily.
• Fit a solid cedar lid with a slight overhang, weighed down with a brick or strap.

The lid is not just for looks. It sheds rain, keeps the heap from turning sodden and helps keep pests out. In very wet weather, you may still need to cover the open slats with a breathable sheet, but cedar’s natural ventilation usually does the job.

Filling It Well: Greens, Browns and Orchard Waste

Composting is a partnership between nitrogen-rich “greens” and carbon-rich “browns”. Aim for roughly one part greens to two or three parts browns by volume, then adjust as you learn how your heap behaves. In an orchard, you have a wonderful supply of both.

• Greens: kitchen vegetable peelings, tea leaves, coffee grounds, grass clippings, young weeds, fruit drop, spent annuals.
• Browns: fallen leaves, straw, cardboard, shredded paper, woodchip, prunings chipped small, dead plant stems.
• Keep out: meat, fish, dairy, cooked food, dog or cat waste, diseased wood, perennial weed roots and anything treated with persistent herbicides.

Chop or crush bulky material. A whole cabbage leaf or a long apple branch will slow the heap down, while shredded prunings and torn cardboard give microbes more surface area. Sprinkle a little soil or finished compost between layers to introduce useful organisms.

Keeping the Heap Active and Pest-Free

Air and moisture are the two things to watch. Squeeze a handful of compost: it should feel like a wrung-out sponge. If it is dry, water gently as you turn. If it is slimy and smells sour, add more browns and turn it to let air in. A well-built cedar bin makes this easy because you can fork material from one bay to the next, mixing the outside to the inside.

Turn the heap every two to four weeks in warm weather, less often in winter. A hot heap will steam gently and shrink quickly. Pests are rarely a problem in a properly managed bin: keep the lid on, bury food scraps in the centre, and avoid adding oily or cooked waste. The mesh base and tight cedar slats do the rest.

Using Finished Compost in the Orchard

Finished compost is dark, crumbly and smells earthy. It should no longer resemble the ingredients you put in. Spread it as a mulch around fruit trees, cane fruits and strawberry beds in early spring or autumn, keeping it a few centimetres clear of trunks and stems. It feeds soil life, improves drainage on heavy clay and helps sandy soils hold water.

You can also sieve a finer batch for potting mixes or use it to top-dress vegetable beds. A cedar bin built this autumn will repay you for years, turning orchard prunings, fallen leaves and kitchen scraps into something quietly extraordinary. Start with one bay, learn your heap’s habits, and let the cedar do the hard work of holding it all together.