Mulching Explained
A blanket for the soil that does five jobs at once
Mulch is any layer spread over bare soil: compost, straw, leaves, bark, even cardboard. It keeps moisture in, suppresses weeds, steadies soil temperature, feeds soil life as it breaks down, and stops rain from compacting the surface.
How to apply it
Wait until the soil is moist and reasonably warm, then spread five to eight centimetres, keeping it a few centimetres clear of stems. Top it up as it thins. Coarse mulches like bark suit paths and perennials; fine, rich ones like compost suit vegetable beds.
Common mistakes
- Mulching cold or dry soil, which locks those conditions in.
- Piling mulch against stems and trunks, inviting rot and pests.
- Using thick wood chips on a vegetable bed, which can lock up nitrogen.
- Laying mulch so thin that weeds push straight through.
Bare soil is an emergency. Nature covers it within weeks β usually with weeds, unless you do it first.
Almost any organic material works if it is not diseased or full of seed. See mulch for a fuller list of materials.
