Scaling up cold bays
This system uses two or three cold bays side by side, moving material from one bay to the next as it decomposes. Turning material between bays improves aeration and speeds things up slightly.
Larger multi-bay systems allow community gardens to process greater volumes using familiar methods. Typically 3 or 4 bays.
Pros: more organised, faster than a single bay, good volume handling.
Cons: takes up space, more physical effort avoids being truly “hot.”
Hot bins
Hot bins are insulated containers designed to encourage rapid microbial activity, generating high temperatures. With the right balance of materials, compost can be ready in weeks. Hot composters can also handle more diverse materials compared to cold bins — ideal for busy gardens with constant inputs.
Many gardeners use the Green Johanna, but there are plenty of other great options on the market.
Pros: very fast, kills weed seeds and pathogens, compact and tidy.
Cons: more expensive, needs careful balance of greens/browns and moisture.
Tumblers
Tumblers are sealed compost bins mounted on a frame that rotate to mix contents easily. Turning improves aeration and speeds decomposition compared to static cold systems.
Compost tumblers create faster, more contained composting that reduces pests and odours — helpful for gardens with limited volunteer time or where neighbours are close by. E.g Joraform
Pros: easy turning, neat, pest-resistant, faster than cold composting.
Cons: limited capacity, can dry out, often don’t get hot enough for weed seeds.
