All soils are made up of 3 basic ingredients in varying quantities:
The relative amounts of each of the above will determine the type of soil you have and how it should be treated.
These soils are ‘heavy’ but fertile. Clay is a critical element in all soils because its unique layered structure at molecular level is negatively charged. This allows it to capture positively charged nutrients such as nitrogen preventing them from being washed or leached out of the soil. The captured positively charged nutrients are only released when plant roots produce positively charged atoms which are swapped for the nutrients.
So clay in soil is generally a good thing. That’s said too much and your soil will be sticky and difficult to work and as the clay particles pack closely together particularly if you walk on the surface the soil will have very few air pockets in it which the plants roots need to survive and grow. In spring a heavy clay soil will be water logged and cold while in summer it will dry out and crack badly.
Dealing with a clay based soil requires you to dig in quantities of well rotted manure and for smaller areas applying course grit will help increase drainage.
Sandy soil is light and free draining but is very poor at retaining nutrients and holding water during the dry summer months. In the spring it warms up quickly which ensure that plants get a good start but unless fed and watered regularly they then can fall back.
To improve a sandy soil add large quantities of organic matter such as peat or well rotted manure and mulch the soil regularly throughout the season to prevent water evaporation. Silt Soil
This is a soil where the particles are bigger than clay but smaller than sand. This type of soil is fertile and reasonably free draining but like clay soils are easily compacted. Working with a silt soil is similar to a clay soil but less difficult. The quantities of organic matter and the need for the application of course grit are less.
Loamy soils contain good quantities of sand, silt and clay and are in many ways the best soils to start with. They are good at holding nutrients, free draining and fertile. They warm up quickly in the spring and yet retain water reasonably well during the summer.