Building Soil That Actually Grows Things

2 min read · Last reviewed February 2026

Feeding plants is a short-term fix. Feeding the soil is what makes a garden easy.

Soil does three jobs: it anchors roots, it holds water and air in the right balance, and it releases nutrients. Fertiliser only touches the third. Most struggling gardens have a problem with the second.

Diagnose structure with your hands

Take a moist handful and squeeze. If it forms a sticky ribbon, it is clay-heavy: nutrient rich, poorly drained, slow to warm. If it collapses immediately and feels gritty, it is sandy: fast draining, quick to warm, hungry. A crumbly ball that breaks under light pressure is loam.

Organic matter fixes both extremes

This is the counterintuitive part: compost improves clay and sand for opposite reasons. In clay it opens pore space so water drains and roots breathe. In sand it acts as a sponge, holding water and nutrients that would otherwise wash straight through.

Soil type	Main problem	Annual treatment
Heavy clay	Waterlogging, compaction	2-5 cm compost on the surface, never dug in wet
Sandy	Drying out, nutrient loss	5 cm compost plus mulch to slow evaporation
Chalky	High pH locking iron	Compost and acidifying mulches; choose tolerant plants
Silt	Capping and crusting	Compost plus permanent planting to protect the surface

Stop digging it in

Surface mulching lets worms and roots do the incorporation, which preserves the fungal networks and the pore structure that digging destroys. Beds mulched annually and left undug outperform dug beds within two or three seasons, with less work.

Test pH before you buy anything

A cheap test kit prevents the most common wasted purchase in gardening. At the wrong pH, nutrients already present in the soil are chemically unavailable, so adding more of them changes nothing.

How much compost is enough?

Two to five centimetres spread on the surface each year is the standard maintenance dose. More is rarely harmful but the returns flatten quickly.

Is homemade compost as good as bagged?

Usually better, because it is fresher and more biologically active. Bagged products are more consistent and matter more when you need a known volume for a raised bed.

Run the numbers for your own project

Composting CalculatorWhat ratio of greens to browns does my compost need?
Raised Bed Soil CalculatorHow much soil do I need to fill my raised bed?
Mulch CalculatorHow much mulch do I need for my beds?