A beginner's guide to composting

Composting is a wonderful way to solve two problems; the amount of food waste we send to landfill, and the need to buy compost from garden centres in plastic bags. With a little time and effort, you can make your own nutrient dense compost in a few months. Here you’ll find an overview of composting, including the two most common types and some common issues. 

Cold composting

What it is: A slow, low-maintenance process where organic matter decomposes at ambient temperature. 

How it works: You simply add kitchen scraps and garden waste to a pile or bin and let nature take its course, with no frequent turning needed. 

Pros: 

• Very easy, minimal work 

• Great for beginners or small households 

Cons: 

• Takes 6–24 months 

• May not kill weed seeds or plant pathogens 

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How you can start cold composting: You can either purchase a plastic composting bin, or construct one out of materials such as wooden pallets. If you opt to buy one, we recommend using second hand sites to find a used one, rather than buying new. Pallet composters are a great way of keeping costs down; many builders merchants and traders get rid of pallets for free. In the coming weeks, you’ll be able to find a guide on making your own pallet composter here on the Gibby Gardening blog. 

Hot composting 

What it is: Actively managed composting where the pile heats up (130–160°F / 55–70°C). 

How it works: You need the right balance of greens (nitrogen) and browns (carbon), plus enough size (at least 1 metre cubed) to trap heat. Turn the pile often for oxygen. 

Pros: 

• Breaks down material quickly (weeks to a few months). 

• Kills weed seeds and many plant diseases. 

Cons: 

• Requires effort: monitoring, turning, watering. 

• Needs a good amount of material to maintain heat. 

How you can start hot composting: You’ll need a larger pile than for cold composting—ideally at least 1 cubic metre to trap and maintain heat. You can either purchase a dedicated hot composting bin (like insulated tumblers or specialized hot composters), or, as with the cold compost, build one yourself. Once again, be sure to check second-hand options before buying new. To keep the pile “cooking,” add two parts brown materials and one part green, chop materials into smaller pieces, and turn the compost every few days to supply oxygen. Regular turning helps the pile heat up quickly and break down materials in just a few weeks to months. It can also be helpful to have a compost thermometer to keep an eye on how hot your compost is getting. 

Overall comparison: 

Cold compost: Great option if your goal is mainly to reduce landfill waste with minimal hassle. 

Hot compost: Best if you want quick compost and don't mind the extra work 

What to compost (and what to avoid): 

Greens (Nitrogen): fruit/veg scraps, coffee grounds, tea bags (no plastic), fresh grass clippings.

Browns (Carbon): dry leaves, shredded paper, cardboard, straw, sawdust (untreated wood).

Extras (in moderation): crushed eggshells, nut shells, hair, natural fibers. 

Avoid: 

• Meat, bones, dairy  

• Oily/greasy foods 

• Cooked food 

• Diseased plants or weeds with seeds 

• Pet waste 

Common issues and solutions: 

Smelly compost (rotten eggs/ammonia): Too many “greens.” Add browns (leaves, cardboard) and turn the pile. 

Dry and not decomposing: Needs moisture and greens. Add water and/or kitchen scraps. 

Attracting pests: Bury food scraps under browns; avoid meat, dairy, oily foods. Use a closed bin if needed. 

Pile too slow to break down: Chop scraps smaller and turn for airflow. 

Happy composting, and look out for our DIY pallet composter guide!