There are three main types of soil. These are clay, silt and sandy.
Soil texture (the way a soil feels) is determined by the proportion of each type of particle so a sandy textured soil has a high proportion of sand particles.
Soil structure is how those particles are bound together to form aggregates or lumps. The ideal soil has aggregates of between the size of a grain of rice and a pea. This soil is easy to work, drains well and allows freedom for roots to penetrate and grip.

So, how do we get from the soil we have to the soil we want? Well, if you have a clay soil, you have soil which is more than 25 percent clay particles. Clay particles are less than 0.002mm in diameter and so create a dense soil. Air pores are tiny so drainage may be slow and the particles stick together to form hard lumps or hardpan in summer. So, it is heavy when damp and hard in summer. Adding organic matter will improve the structure of this soil because it will encourage the break up of lumps and act as a glue to stick tiny particles together into larger ones. It will also encourage beneficial organisms like worms who will drag organic material down into the soil, not only improving its structure but creating drainage channels and air pores in the process.

Digging well just before frosts and leaving clay soil over winter means that it will freeze and thaw several times. This helps break up clods into smaller aggregates too. Keeping heavy machinery off clay soil will also reduce compaction. Adding coarse sand will also open up the soil and improve drainage.

Silty soil have a mix of sand and clay particles and will form a soil which is silky to touch, drains fairly freely but still is sticky and can form lumps in summer. Again, organic material can help improve structure. Checking the pH of silt and clay soil is beneficial too and you can add lime if it is too acidic.

Sandy soil is made up from a high proportion of sand particles. These can be coarse or fine but range from 0.02 to 2mm in diameter. Air pores are large. Sandy soil drains very readily and with the water, nutrients are leached out so it is a very hungry soil needing regular feeding to maintain nutrient levels. It is light and easy to work but can provide little anchorage for some plants. Organic material will help bind particles together and also provide a slow release source of nutrients to the soil. Regular applications will see the structure improve as more organic material is incorporated into the soil.

One of the problems with any kind of soil can be the sub soil. Although you should never mix sub soil with top soil, it is important to dig down and see how thick each layer you have is the what the subsoil is as it can differ from topsoil in many ways.
For example clay hardpan as your sub soil will impede drainage whatever topsoil you have so it is important to break this up using a pickaxe or tiller before replacing the topsoil.

Whatever type of soil you have, there is a way to improve it over time. Organic material seems to benefit all soils and provides nutrients too.

Learn more about this author, Sammy Stein.
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