Soil and Rotation principles
In order to work out your soil type you need to get your hands dirty!
Sandy soil (also known as light soil) is gritty to touch– you will be able to feel sandy grains when you rub your fingers through it. This type of soil will drain quickly and heat up quickly, but it will often lack nutrients and be very acidic.
Clay soil (also known as heavy soil) is sticky when wet and when rolled between your fingers it will have a shiny finish to it. This type of soil is slow draining and takes a long time to warm up, but in the summer it will bake hard, leaving wide open cracks on the surface.
Silt soil can be easily compacted in your hands, it will hold more water than sandy soils but are not as heavy as clay soils. If the soil is left unplanted it can become eroded by the wind.
Loams are a mixture of the best bits of clay, sand and silt. It is fertile, well-draining and easy to dig.
Chalky or lime-rich soils are largely very alkaline, made up of calcium carbonate
Testing your pH level
The acidity of your soil will also help you to identify which plants you can grow more easily and if you need to add extra improvers to the soil. Soil testing kits can be bought at garden centres and cost very little.
pH 3.0 – 5.0
Very acidic soil, tends to be lacking most nutrients. Add lime and nutrients back into the soil
pH 5.1 – 6.0
Acidic soil, add lime unless you plan to grow ericaceous plants
pH 6.1 – 7.0
Moderately acidic soil, loved by most plants, high in nutrients and worm activity
7.1 – 8.0
Alkaline soil, some nutrients are lacking, but the brassicas family prefer this type of soil as risk of club root disease is minimised
If your soil is on the acid side then you can apply garden lime to make it more alkaline. If however your soil is very lime rich (alkaline) then you can use acidifying materials like sulphur – it all depends on what fruit and vegetables you wish to grow.
All soils can do with being conditioned from time to time, adding back in the precious nutrients lost over seasons of growing. Some soil testing kits will also be able to provide you with the levels of nutrients found in your soil – and so tell you want you need to add in order to make it rich again e.g. potash, phosphate, magnesium, nitrogen etc. Alongside this, it is always worth adding bulky organic matter to your soil every year (good rotted compost, that is dug well in) to help improve the general fertility of your soil and its ability to retain moisture during the summer. CLICK HERE to read about allotment soils.
The Soil is Alive - click on the title to read the brochure from the International Office
After setting aside a section of your plot for perennial crops such rhubarb and asparagus, every new plot-holder needs to give some thought to crop rotation. This helps to ensure that you do not get a build -up of pests and diseases in the soil, groups plants with similar nutritional needs together and helps to build soil fertility. Crops such as sweetcorn, squash and salads can be fitted in suitable places around the plot but take care not to grow them in the same spot every year. Some gardeners follow a 3 year rotation schedule. Click on the image for a pdf of the 4 year rotation plan.
Another vital ingredient for a healthy soil are worms! Find out more about these fascinating creatures at the Earthworm Society of Britain.