How to improve your soil

Improving soil is different from simply adding fertiliser. Although fertiliser contains key nutrients these are used up fairly quickly, and it won’t do anything for the structure, or longer term fertility of the soil. For that, you need to add organic matter, and it’s worth doing once every year. Late autumn is a good time to prep your beds and borders because the garden is quiet and ready for the winter, but any time from late autumn to early spring will work. The advantage of autumn is that, once done, your soil has months to ensure that any organic matter is incorporated into the soil ready for the spring.

Soil Types

Most soils tend towards one of four categories: sand, silt, clay, or loam (which has a balance of sand, silt and clay). Each soil type has its own characteristics.

Sandy Soil

Sandy soils, also described as light soils, are made up of very large particles and has a gritty texture. Sandy soils drain quickly and don’t hold onto nutrients very well. However they are easy to work, and warm up quickly in spring. Root crops, onions and asparagus will all grow well in sandy soil.

Silt Soil

Silt soils have smaller particles than sandy soils, giving them a slightly slippery, floury feel. This type of soil holds onto moisture and nutrients for longer.

Clay Soil

Clay (or heavy) soils consist of very fine particles. Clay soil holds its shape when rolled into a ball and is smooth to the touch. It is slow both to absorb moisture and to drain, which means soils like this can bake hard in summer then become waterlogged in winter.

Well-cultivated clay soils are preferred by brassicas such as cabbage, as well as beans, peas and leafy crops like salads.


Loam is the ideal soil type for growing fruits and vegetables. It’s fertile, drains well, is easy to work and contains plenty of organic matter that supports just about any crop.

How to Improve Your Soil

All soil types can be improved by adding organic matter to it. Organic matter can take many forms, for example leaf-mold made from decomposed leaves; farmyard manure that can be guaranteed to be free of all traces of herbicides; or good old-fashioned garden-made compost.

Organic matter of any type should be well rotted so it can easily be incorporated into the soil. And to avoid future problems, check it for roots of pernicious perennial weeds such as bindweed.

Organic matter works to improve both soil structure and nutrient content. In light, sandy soils it works as glue, binding particles together to improve its ability to retain moisture and nutrients. Conversely, it opens up heavy clay soils so they can drain more easily. But no matter what your soil type, it will truly benefit from regular applications of organic matter to feed and sustain the plants grown in it.

How to Use Organic Matter

You can add organic matter at any time of year, but the end of the growing season is an especially good time. Barrow it onto vacant ground then spread it out to a depth of at least two inches (5cm). Leave it on the surface over winter, and by spring worms will have done a great job of incorporating most of that organic matter into the soil. Any remaining on the surface can always be forked in a few weeks before it’s time to sow or plant.
Organic matter may also be laid around established fruit trees, shrubs and canes, and around perennial vegetables such as artichoke or asparagus. Do this towards the end of winter.

Testing Soil pH

Soil pH determines whether a soil is acid, alkaline or somewhere in-between. Knowing your soil’s pH will help you to decide what to grow in it. For example, particularly acidic soil is great for acid lovers like blueberries, while soil with a higher, or alkaline pH is preferred by brassicas such as cabbage.

Test your soil using a pH test kit. The accompanying color chart will provide a guide to your soil’s pH so you know whether it’s acidic, neutral or alkaline. For best results test the pH over several parts of your plot to get an idea of whether it varies or not. You can then decide which areas to improve.

For example, soil can be improved for brassicas by adding garden lime, which works to raise soil pH so it’s more alkaline. Adding organic matter will generally move pH towards a level ideal for most fruits and vegetables.

Getting more familiar with your soil means you can keep it in tip-top condition. Your crops will love you for it! Let us know what soil type you’ve got, and how you look after it, in the comments section below.