How to improve your soil

The key to growing healthy plants and bumper batches of vegetables is your soil. Not all soil is the same and the type you have can seriously affect the growth of your plants. Here, Compost Direct shares their tips for identifying the type of soil you have and explaining how to improve it.

Types of soil

There are a number of different soil types and the soil you have will determine the type of plants you can grow successfully. Some of the most common types of soil include:

Clay soils

As the name suggests, clay soils are made up of over 25% clay. Plenty of nutrients are usually found within the clay, but the soil retains a lot of water and is slow to drain. The soil is easily compacted when wet and can dry out and crack on hotter days.

Look out for:

  • Soil that is sticky when wet
  • Soil that can be rolled into a sausage

Improving clay soils

One of the main issues gardeners with clay soils face is making the soil more manageable to work with. Here’s how to improve your clay soil:

  • Time it right. As we’ve already mentioned, clay soils can dry out and bake during the summer, making it increasingly difficult to work with. The best time to work with clay soils is in autumn, when it’s moist but not too dry or overly wet, like they can be in winter or spring.
  • Work on boards. Another problem with clay soils is how heavy it is and how compacted it can become. Try to avoid walking on it wherever you can or consider laying down wooden boards to balance your weight more evenly as you work and minimise compaction.
  • Break it down. Adding organic matter — like well-rotted manure or an organic plant food, for example — will break down clay soils. This will not only make it more manageable to work with, it will make the clay’s many nutrients more readily available to plant roots, aiding plant growth.

Sandy soils

Sandy soils are made up of a lot of sand and very little clay. Unlike clay soils, this type of soil drains quickly, which can often mean that nutrients are washed away and lost. Because sandy soils contain few nutrients to begin with, this can become problematic.

Look out for:

  • Soil that feels gritty
  • Soil that falls through your fingers and cannot be rolled into a sausage

Improving sandy soils

The main issue with sandy soils is that nutrients and moisture drain too quickly out of them. There are ways to combat this issue:

  • Add organic matter. Well-rotted manure or other organic matter acts as a sponge when added to sandy soils, holding water and preventing nutrients from escaping.
  • Work in the spring. It’s best to work when your soil is still wet, so there’s plenty of water already there for you to retain. Spring is a great time to do this, as your soil will still be wet from winter.
  • Apply a top layer to your soil. A layer of stones or mulch around your plants adds an additional barrier to your soil, helping to protect it from drying out.

Silt soils

Although silt soils are fertile and well-drained, they can be easily compacted. They are easier to work with than other types of soil but are not common.

Look out for:

  • Soil with a slippery texture
  • Soil that is difficult to clump

Improving silt soils

Improving silt soils is a lot like improving clay soils. The main problem to overcome is compaction and can be done by:

  • Applying organic matter. Silt soils are generally fine and lightweight. This means they could be affected by the wind. Adding organic matter will stabilise this type of soil, making it thicker yet still workable.
  • Work on boards. Like clay soils, silt soils are easily compacted, so work on boards to avoid flattening the soil and damaging its structure.

Peat soils

This type is the holy grail of soils! Fertile and moisture-rich, peat soils are usually not found in gardens — so if you have it, you’re very lucky!

Look out for:

  • Dark-coloured soil
  • Soil that feels spongy when squeezed

Improving peat soils

Because peat soil is so fertile and sought-after, it generally doesn’t need to be improved. However, if you need to boost the growth of your plants, a fertiliser can help.


Chalky or lime soils.

A usually stony soil, chalky or lime-heavy soils can contain high levels of calcium carbonate or limestone.

Look out for:

  • Soil that froths when a sample is placed in vinegar

Improving chalky or lime-heavy soils


Soil that is heavy in chalk or limestone can cause organic matter to decompose rapidly, so adding it to the soil isn’t a plausible option. Likewise, adding sulphur to reduce the alkalinity of the soil is not an option, as a huge amount of sulphur would be required over an extended period to lower the levels.

Instead, it’s often an easier and more sensible option to simply work with the soil you have. Choose plants that can grow in alkaline conditions and develop your garden around the type of soil you have.

By identifying the type of soil you have, you can make working in your garden more manageable and enjoyable, and improve the growth of your plants in the process.

27th September 2016

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