Composters

A compost bin is best placed in a semi-shaded, sheltered spot in the garden on natural, loose soil, rather than on concrete, paving or plastic sheeting. This allows earthworms and microorganisms to colonise the compost and excess water to drain away. Full sun dries out the compost, whilst deep shade slows down the composting process. It is best to keep a distance of at least 50 centimetres from the property boundary. For thermal composters, a fine-mesh ground grid is recommended to protect against voles and rats.

The compost bin is for raw plant-based garden and kitchen waste such as fruit and vegetable scraps, coffee grounds, eggshells, grass clippings, leaves and prunings. Do not put cooked food, meat, fish, dairy products, large quantities of bread, cat litter, dog faeces, treated wood or diseased plants in the composter, as these attract rats or spread disease. The ideal mixture is a combination of moist green material and dry brown structural material in a ratio of about 1 to 2.

A compost bin is filled in thin, alternating layers of moist, nitrogen-rich material and dry, carbon-rich material, in a ratio of about 1 to 2. A 10 to 15-centimetre-thick drainage layer of wood chips or shredded branches is placed at the bottom, with layers of grass clippings, kitchen waste and leaves alternating with wood chips or cardboard on top. A thin layer of mature compost in between speeds up the composting process. The contents should be as moist as a wrung-out sponge.

Which compost bin is right for you depends on the size of your garden, the amount of waste you have and how quickly you want the compost to be ready. For small to medium-sized private gardens, a closed plastic thermal compost bin is usually the most practical choice: it shortens the composting process to around 8 to 16 weeks thanks to thermal insulation, works all year round and keeps odours and pests at bay. Wooden and plug-in composters are usually large and are therefore suitable for large gardens with plenty of garden waste. Worm bins and bokashi buckets are particularly suitable for balconies and kitchens.

For most households, a thermal composter is more practical than an open composter because it works faster, can be used all year round and provides better protection against odours and pests. Composting takes around 8 to 16 weeks in a thermal composter, compared with 6 to 12 months in an open composter. Open systems are particularly suitable for large gardens with plenty of garden waste and little kitchen waste. In practice, a combination of both systems can also be a good idea.

A thermal composter is a sealed composter made of insulating plastic, which traps the heat generated during composting inside, thereby significantly speeding up the process. At its core, microorganisms reach temperatures of 40 to 70 degrees, which reduces weed seeds and pathogens. Ventilation slits provide oxygen, whilst a removal flap at the bottom makes it easier to remove the compost. Ready-to-use compost is produced in 8 to 16 weeks, whereas an open compost heap takes 9 to 12 months.