Make and troubleshoot garden compost

When to do it

Whenever suitable garden and kitchen material is available.

What you need

• Ventilated bin or heap
• Green material and dry brown material
• Fork, gloves and water

How to do it

1. Choose a reachable, draining site. Collect vegetable scraps and fresh trimmings as greens, and dry leaves or torn plain cardboard as browns.
2. Mix the materials rather than making a thick grass layer. Start with roughly equal volumes, adjusting as the pile changes; chop bulky pieces.
3. Keep it damp like a wrung-out sponge, with air spaces. Exclude meat, dairy, pet waste, persistent weeds and suspect diseased plants from this beginner heap.
4. If it smells sour and feels soggy, mix in dry browns and turn it. If dry and unchanged, add water gradually and fresh greens. A small cool pile can decompose without becoming hot.
5. Let a batch finish without fresh additions. Use it when dark, crumbly and earthy, with most ingredients unrecognisable; screen out woody pieces. Use as soil improver, not a complete seed-raising mix.

What success looks like

• The material shrinks and becomes earthy rather than sour.
• Finished compost does not resemble fresh scraps.

Watch out for

• Assuming every home heap kills weed seeds or pathogens.
• Adding more water to a wet, airless pile.

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