Topsoil and compost: what's the difference?

Most gardening advice gives great tips on how to create and use garden compost, but not everybody understands the difference between this and a high quality topsoil. We explain exactly what topsoil is and why buying topsoil is a good alternative to costly and time-consuming compost making.

What is topsoil?

If you dug down through a section of your garden soil, you would see that the topsoil is relatively shallow. It is, however, the layer of the soil out of which all of your garden plants grow. Topsoil contains everything you would find in your garden soil, including nutrients for your plants and organic matter.

What is topsoil used for?

Topsoil is useful for adding depth to shallow garden soil, for improving the quality of garden soil, for making new planting areas or for putting under a new or replacement lawn.

What are the advantages of topsoil over compost?

Whilst compost has more nutrients than topsoil, topsoil isn't without its advantages. Topsoil is far better at retaining its structure and holds much needed moisture far longer than compost. It is also generally cheaper.

Is compost ever a better choice than topsoil?

When plants are grown in pots, they have less access to nutrients than those planted directly into the soil. The more crowded a pot - for example, a summer hanging basket - the less nutrients are available for each plant. Compost is better than topsoil for these situations because it has more organic matter, added nutrients and often a slow-release fertiliser.

Can I mix topsoil and compost?

Mixing topsoil and compost is a great way to make your own potting compost. This mixture will dry out less slowly than compost, because of the water-retaining and structure-holding features of topsoil.

Are there different types of topsoil?

Topsoil is generally available as 'screened', where all additional matter such as small stones has been removed, and 'value', which may retain some original debris but is still a good growing medium. Value topsoil is usually recommended for those with budget restraints or bulk fill requirement, whereas screened topsoil is suited to most garden requirements. We stock a large range of both, found on our topsoil page. It also possible to buy specialist topsoil for lawns and turf, for fruit and vegetables and with no added peat. All bought topsoil should have a neutral PH value of around 7 - check out the RHS' detailed spec for different types of topsoil.

How can I buy topsoil?

Topsoil is available in a range of amounts to suit most garden jobs. Bulk topsoil is delivered by truck and tipped loose whereas bagged topsoil can either be delivered in 'dumpy' bags or smaller bags.