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23 November 2020

Best composts for raising young plants

Before planting your seedlings and small plug plants, look at our round-up to find out which compost will give them the best chance of growing big and healthy
Adele Dyer

Young plants, such as seedlings and plug plants, need a compost with enough fertiliser to let them grow well, but not so much that it burns their roots. It also needs to retain enough water, while not drowning young plants in soggy compost. 

However, as there is no way to know how well a compost will work by simply reading the ingredients or paying through the roof, we decided to test them for you. 

We selected 25 different composts and grew cabbages and antirrhinums over a six week period. The best produced large, flowering plants, while the worst made tiny, pale-leaved cabbages. 

Only one compost scored well enough to be a Best Buy this year. Find out the results in the table below.  

New test results will be available in January 2021. 

Best Buy composts for raising young plants

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Compost Our verdict Young cabbage plants Young antirrhinum plants Score
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Member content
Great peat-free compost

Peat content: 0%

Price: £7.49 for 50L

Price per litre: 17p

This peat-free compost has been a Best Buy several times in the past and, although it’s not sold as widely as some composts, we think it’s worth seeking out. It’s a mix of composted bark and wood fibre with a little coir.

Both the cabbage seedlings and antirrhinum plug plants quickly matured into large, healthy plants with good foliage colour. The antirrhinums flowered well and looked healthy at the end of the test.

Where to buy: Garden centres. Find stockists at melcourt.co.uk

Not found the right product for you? Browse all our compost reviews

Things to look for when buying compost for raising young plants 

Here are two useful features to look for when buying your compost:

  • Good structure and aeration - it encourages strong root development. 
  • A medium-crumbly texture - fine compost can be prone to water logging 

For more advice on choosing the best compost for you, head to our compost buying guide

Why Which? compost reviews are better

Which? is independent and doesn't accept advertising or freebies, so you can trust our reviews to give you the full, honest and impartial truth about a product.

Before testing we send out secret shoppers to buy all our compost so we know we are getting the same product as you. 

We then grow cabbage 'Caraflex' seedlings from the two true-leaf stage, and Antirrhinum 'White Appeal' in 25 different composts over six weeks. 

After six weeks, we judged both the young plants on how vigorous they were, which includes looking at size, leaf colour, and whether the plants are stocky and strong or long and straggly. We also noted how well the antirrhinums were flowering. 

To find out more, head to how we test compost. Alternatively, browse all our compost reviews