What’s the difference between soil and compost?

On the surface, topsoil and compost may seem like very similar materials.  Both are made up of broken down organic matter and contain nutrients perfect for plants or turf.

The difference between Topsoil and Compost comes from how they are produced.  Topsoil is made from organic matter which has disintegrated over a long period of time while with Compost the disintegration happens much faster in a warm, damp environment.  Due to this, Compost contains much more nutritional content than Topsoil does however, Topsoil maintains its structure and retains moisture better than Compost.

Generally if you are looking to increase the volume and improve the structure of soil in your garden, Topsoil would be the best choice whereas Compost is ideal to inject nutrients into your soil.  It’s also common to use a combination of both to maximise the benefits however compost can be used on its own for pots and planters.

Types of compost

There are numerous types of compost available but by far the most common is Multi-Purpose (or All-Purpose) compost which is available in a number of different sizes.  More specialised compost is available for specific plants (such as Houseplants and Ericaceous plants) or, specific purposes like seed sowing.

Peat-Free vs Peat Based Compost

Peat has generally been used as one of the main components in compost for many years, environmental concerns now mean that peat is being phased out of compost and there are a number of peat-free alternatives available.  England & Wales banned the use of peat in retail horticulture back in 2024.  Scotland is still at the consultation phase, as of end 2025 there is no date set for when peat will be banned in Scotland.  This means we carry a mixture of both types of compost.

Instead of using peat, peat-free composts generally contain green waste, wood and/or coconut fibres. These can cause the texture of peat-free compost to be much rougher and less friable.  It can also create the perfect living conditions for certain types of harmless fungi. It is not uncommon for white deposits to be visible when a bag is opened. This is natural, the compost is not damaged in any way and there is no risk to any plants.

In simple terms, peat-free compost is better for the environment however peat based compost is generally better for plants.   

Peat-Free compost also contains less nutrients so plants may need to be fed more often.  In general it also requires more frequent watering, but not necessarily a larger volume of water.

Specialised Composts

Seed & Cutting – A extra fine grade of compost, little to no larger particles.  This ensures that seeds have good contact with the surface of the compost and, cuttings have a better chance of rooting successfully.  It may also have additional moisture retention (such as added vermiculite).

Ericaceous – A family of plants that thrive in acidic soil, general compost has a neutral pH so it is not suitable for them. Ericaceous plants include Rhododendrons, Azaleas, Acers & Hydrangeas. A more definitive list can be found here.

Houseplants – Houseplants generally require a compost with more grit or loam to ensure proper drainage.

How much do you need?

Unfortunately, there is no such thing as a ‘normal’ or ‘just’ a bag of compost.  It’s a very good idea to check how much you need in advance or at the very least measure the container or area you want to add the compost to.  As well as the different types of compost available there are different sizes ranging from 10ltr up to 90ltr.  If you are filling a pot it may have the size printed on it so it’s worth checking.

See our on-line shop for our current range of composts