How to use compost in your garden

Compost: black gold for your garden

Well-made compost smells like a woodland floor after rain. It's dark, crumbly and teeming with life. Pick up a handful and you'll feel worms wriggling between your fingers. That's exactly what you want, because those creatures do the heavy lifting in your soil.

GardenWorld helps you visualise a garden design suited to your soil type. That way you know exactly where and how much compost your garden needs.

When to spread compost

The best time is early spring, once the frost has left the ground. March and April are ideal. You can also apply a layer in autumn and let it work in over winter. Aim for about 3 to 5 centimetres per square metre. Sounds modest, but it transforms your soil.

Garden centres and RHS partner shops sell bagged garden compost if your own supply runs short. Bear in mind that homemade compost is richer in soil life than shop-bought alternatives.

Compost in ornamental borders

Spread compost around your perennials but keep a few centimetres clear of the stems. Let the earthworms work it in. No need to dig or rotavate. That would destroy the soil structure you're trying to build.

Compost in the veg patch

In the vegetable garden, you can lightly work compost into the top layer. Heavy feeders like courgettes, squash and tomatoes love a generous helping. Light feeders like carrots and onions need less. Adjust the quantity to match what you're growing.

How much compost do you need?

A rule of thumb: three wheelbarrows per 10 square metres for an average garden. Clay soil benefits from a bit more, as compost lightens heavy ground. Sandy soil gets better moisture and nutrient retention. Check the packaging at your garden centre for calculator guides.

Common mistakes

Not all compost is equal. Half-rotted compost can actually pull nitrogen out of your soil rather than adding it. If your compost still smells sour or contains recognisable scraps, it isn't ready. Give it a few more weeks.

Too much compost is also a thing. Some gardeners add a fresh layer every month. That can create a phosphate surplus, which harms soil organisms. Once per season is plenty.

Compost as mulch

A thin compost layer (2-3 cm) makes excellent mulch. It suppresses weeds, retains moisture and feeds the soil all at once. Apply it after clearing weeds from the bed.

Mixing compost with other materials

Combine compost with leaf mould for an extra airy texture. Or mix it with sharp sand for clay ground. Some gardeners stir in a handful of rock dust for added minerals. These aren't compulsory additions, but they can boost results.

Get going with compost

Compost is the most rewarding gift you can give your garden. It improves every soil type, feeds your plants and supports soil life. Start small: a bucket per border already makes a difference. Want to know which plants suit your improved soil best? Design your garden at GardenWorld and kick off the growing season well prepared.