Questions and answers

Mineral particles of different sizes (sand, silt and clay), organic matter, water, air and a vast number of living organisms, from bacteria and fungi to earthworms. All these parts are linked, and a change in one affects the others.

Take a handful of moist soil and try to roll it into a sausage. Sand falls apart, a sandy loam barely holds together, a loam forms a sausage that cracks, and clay bends easily into a ring. Peaty soil is dark, light and springy under your fingers.

It is rich in humus, which gives it its dark colour and holds on to water and nutrients, and it has a good crumb structure. It was chernozem that Vasily Dokuchaev studied in his work "Russian Chernozem" (1883), conventionally regarded as the start of scientific soil science.

Soil texture, the proportion of sand, silt and clay, is hard to change. Its properties, however, can be improved noticeably: organic matter helps sand hold more water and makes clay more open. It takes more than one season, but it pays off.

Compost is decomposed organic matter that you dig in or spread over the soil to feed it and improve its structure. Mulch is a surface covering: it protects the ground from drying out, crusting and weeds, and gradually rots down itself.

Straw, dry leaves, wilted grass clippings, bark, wood chips, finished compost. Fresh grass is laid thinly so that it doesn't turn slimy. It is best not to use material containing weed seeds.

Green manures are plants grown not for a harvest but for the soil. Their roots open up the ground, the foliage becomes organic matter once it is cut down, and the crop itself protects the bed from erosion and weeds.

Yes, at least in a simple form. If you don't grow related crops in the same place year after year, their pests and diseases build up less in the soil and nutrients are depleted less often. A simple note of what grew where is a big help.

It expresses soil acidity: 7 is neutral, below 7 is acidic and above 7 is alkaline. Different crops prefer different conditions, so it is useful to know your soil's pH before you plant.

The simplest way is test strips or a home soil meter, which give a rough guide. A laboratory analysis of a sample gives the exact value and the full picture. Indirect signs, such as certain weeds, can be misleading.

Only when a test has confirmed that the soil is acidic and this is a problem for the crops you grow. What to apply and how much depends on the soil type and the test results; check the rates on the label of the product you choose or ask a specialist.

Read the whole label and follow the rates and timings given there. Wear gloves, don't apply products in windy weather, and store them in closed packaging away from children, pets and food. More is not better: an excess harms both plants and soil.