Composting for Beginners: Bins, Balance, and Common Problems

Greens are nitrogen-rich, wet materials such as fruit and vegetable scraps, coffee grounds, and grass clippings. Browns are carbon-rich, dry materials such as cardboard, paper, dry leaves, and straw. Aim for roughly equal volumes, or a little more brown than green.

Smelly, wet compost has too many greens; add shredded cardboard or dry leaves and turn it. Dry compost that is not breaking down needs more greens and some water. A pile that never heats up may be too small or need turning to add air.

Small-space options include worm bins and bokashi bins, which ferment food waste indoors. Many cities also offer kerbside food-waste collection or community compost schemes.

Compost is ready when it is dark, crumbly, and smells earthy, usually after six months to a year. Spread it on beds as a mulch or mix it into potting soil.