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The best compost will provide all the nutrients and support needed for seeds and veg to grow and thrive, while the worst will leave you with meagre crops and feeble plants.
But the only way to know if a compost is good or bad is to grow plants in it and compare them - something we've been doing for more than 30 years.
Many people no longer want to buy peat compost as it's believed to damage the environment and add considerably to global warming. However, peat composts are still the most widely available composts in garden centres and are preferred by many gardeners.
This year we chose to only test peat-free compost. From 2024, you will only be able to buy peat-free compost in garden centres and DIY stores when the government introduces a ban on peat composts. We firmly believe you can get great results from peat-free composts and we haven't used peat in our own trials for many years. We have also included Moorland Gold composts which use peat recovered from lakes and dams after being naturally washed from peat heathland by rainwater.
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Sign up nowThe results are updated in mid-January each year.
Only logged-in Which? members can view our recommendations in the table below. Join Which? to get instant access.
| Price | Tomato | Petunia | Score | |
---|---|---|---|---|---|
B&Q Verve Peat Free Multi-purpose Compost | £7 for 50 litres | ||||
B&Q Verve Seed and Cutting Compost | £6 for 35 litres | ||||
Bronte Peat Free Multi Purpose | £9.99 for 50 litres | ||||
Dalefoot Wool Compost for Seeds | £7.99 for 12 litres | ||||
Fertile Fibre Multi-Purpose Compost | £24 for 60 litres inc. delivery | ||||
Fertile Fibre Original Seed Compost | £24 for 60 litres inc. delivery | ||||
For Peat's Sake! Eco Coir Compost | £8.50 for 11.5 litres |
The results are updated in mid-January each year.
Only logged-in Which? members can view our recommendations in the table below. Join Which? to get instant access.
Peat-free compost for raising young plants | Price | Tomato | Marigold | Score |
---|---|---|---|---|
B&Q Verve Peat Free Multi-purpose Compost | £7 for 50 litres | |||
B&Q Verve Seed and Cutting Compost | £6 for 35 litres | |||
Bronte Peat Free Multi Purpose | £9.99 for 50 litres | |||
Dalefoot Wool Compost for Potting | £11.75 for 30 litres | |||
Fertile Fibre Multi-Purpose Compost | £24 for 60 litres, including delivery | |||
Fertile Fibre Original Seed Compost | £24 for 60 litres, including delivery | |||
Homebase Peat Free Multi-Purpose Compost | £6.75 for 50 litres |
The results are updated in mid-March each year.
Only logged-in Which? members can view our recommendations in the table below. Join Which? to get instant access.
Peat-free compost for containers | Price | Pelargonium | Potatoes | Score |
---|---|---|---|---|
Bronte Peat Free Multipurpose Compost | £9.99 for 50 litres | |||
B&Q Verve Peat Free Multipurpose Compost | £7 for 50 litres | |||
Dalefoot Double Strength Wool Compost | £12.75 for 30 litres | |||
Dalefoot Wool Compost for Potting | £11.75 for 30 litres | |||
Fertile Fibre Multipurpose Compost | £24 inc delivery for 40 litres | |||
For Peat's Sake Eco Coir Compost | £9 for 11 litres | |||
Homebase Peat Free Multi-purpose Compost | £7 for 50L |
We also test grow bags - see our round-up of the best grow bags.
There are two main types of compost: multipurpose and composts for specific use, such as raising plants from seed or growing plants in patio containers.
Try our Best Buy controlled-release feeds
Compost can be as little as 99p and as much as £25, it all just depends on the type and how many litres of compost you get in the bag. It's important to remember that a high price doesn't guarantee quality, though.
In fact, our testing shows really variable results for both cheap and expensive compost. The only way to really know what you're getting is to look at our results.
It's hard to know if a compost is good or bad just by looking at the packaging, but there are a few things to look out for:
It’s best to buy only the amount of compost you need, and use it up as soon as possible. Store compost in a shed or garage where it will be cool and dry, or undercover, especially through wet weather. If you can’t use up peat-free compost within three months of buying it, use it as a mulch on your borders.
When you swap to using peat-free compost, you may notice a few differences from using peat. You will need to water carefully as the top of the compost can often look dry or wet, but the rest of the pot could be wet or dry. Get used to putting your finger into the compost to feel below the top layer. You can also pick up your pots. A light pot will need watering, while a heavy one is probably wet enough. Check your pots regularly as they can dry out quickly.
You may need to feed your plants more frequently if you use peat-free composts. Some don't contain any fertiliser at all and others have fertiliser that runs out quickly. As soon as the growth of your plants slows down, start to give them a liquid feed, including seedlings and small young plants. For more information, look at our reviews of liquid feeds and tomato feeds.
Find out more about why you should buy peat-free compost.
The bacterium responsible for the potentially fatal Legionnaires’ disease has been found in some composts sold in the UK. The chances of you becoming infected are very low, but it makes sense to take the following precautions when handling compost:
Want to go peat-free? Here's our guide on everything you need to know about Peat-free compost: expert guide.
We test compost for three different tasks; sowing seeds, raising young plants and for use in containers.
All three tests are carried out by an expert at a horticultural institute, and the compost for seeds and young plants test takes place in a temperature and humidity-controlled greenhouse. The composts for containers are tested outside once the nights are frost-free. The results are compiled by an independent assessor who's an expert in compost and plant health.
Our trials have also found these useful facts:
Find out more in our guide on how we test compost. Alternatively, jump straight to our round-up of the best controlled release fertilisers. Don't