Topsoil vs Compost
There is plenty of advice out there about compost, and what sort to use, but what about topsoil? When is that appropriate? And is it a reasonable substitute for compost? It can seem like a good option, especially since it is available in bulk, but does it have the same effect?
Topsoil is basically the top layer of the soil, where everything grows (find out more about the definition of topsoil). So if the soil in your garden is very shallow, or you are making new garden beds, adding or replacing a lawn, or putting in raised beds and need to add new soil, top soil is what you need. Top soil comes in three qualities: economy, general purpose and premium, see our topsoil range.
Economy is great if you need to fill large areas and “quantity is more important than quality”. It is unscreened, and as dug, so may contain stones, roots and weeds, but it is cheap. General purpose is, as it sounds, suitable for most garden projects, including laying a new lawn, top dressing lawns and garden beds, and making new garden beds. Premium is the best quality, and should contain no seeds or roots. Nurseries often use it to make up their own potting compost. For most gardeners, and most projects, general purpose will be ideal.
You can buy topsoil from topsoil suppliers, who will usually supply a bulk bag. Although it sounds expensive, you get lots of topsoil, so provided you have a place to store it, this is a good way of buying.
So when is topsoil not ideal? Well, if you’re growing plants in pots, you’ll probably find that topsoil doesn’t really provide enough nutrients. It’s fine where the plants can spread their roots and reach out for more nutrients, but when they’re confined to a pot, it’s not so good. This is particularly the case if you put lots of plants into one pot, as you do when planting up bedding plants in summer. In this case, you need a growing medium with a bit more ‘oomph’ – more organic matter, more nutrients, and possibly a slow-release fertiliser as well. In this case, you’ll need to buy compost. You can mix compost with topsoil to create your own potting compost, as many of the nurseries do, which gives you the advantages of soil – namely that it dries out more slowly and holds its structure better – together with the benefits of compost – organic matter and more nutrients, a compost made with loam or soil is often called a John Innes Compost.
You may also want to add compost when you’re growing plants that are very “hungry”, such as vegetables. They will grow better for the added nutrients, though again, you’ll still need to feed them regularly in order for them to grow properly.
So, here’s the basic rule:
- general gardening projects = topsoil,
- pots or hungry plants = compost.
Don't forget if you need to buy quality topsoil your already in the right place, and you can find out more about compost at our compost website.