How to improve soil water-holding capacity

Improving soil water-holding capacity is largely about improving soil structure. Here are several ways to help keep your soil healthy, and water where it’s needed.

Add organic matter

Organic matter can hold many times its weight in water, but its greater value lies in how it fuels soil biology. Soil microbes and fungi break down organic matter, using it as energy. In the process, they release sticky substances (exudates) that bind particles into stable aggregates, and fungal hyphae help hold those aggregates together and link them into a larger network. Good sources of organic matter are compost, aged manures and fine mulches, like sugarcane and pea straw.

Avoid compaction

Walking on or working the soil can destroy soil pores, especially when the soil is wet. Keep to dedicated walking areas (for example, paths between beds and stepping stones), and if you need to step into beds, placing a wide board down will spread your weight and reduce the degree of compaction.

Grow cover crops

Dense crops such as clover, oats and buckwheat protect the soil surface, but most of the benefit is happening below ground. As roots push through the soil, they create pores and channels. Roots also release exudates that feed soil microbes.

Rotate with deep-rooted plants

Plants such as radish, sunflower and lupin extend roots further into the profile, creating pores and channels deeper in the soil. These plants are sometimes promoted as natural tillers that break up hard ground, but their ability to force through extreme compaction is limited – roots usually follow cracks or turn sideways if soil is very dense.

Alisa Bryce explains in detail the importance of plant available water-holding capacity (PAWC) in the Early Summer 2025 issue, available in newsagents and selected supermarkets. You can also subscribe here and get an issue delivered to your door!