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Tomato Compost Buying Guide

Updated: October 2026

You can stand in front of three sacks that all mention vegetables and still not know which one will fill your tomato pot. A useful tomato compost buying guide starts with the job: how many plants you have, whether they are going into pots or a planter, and how much compost that format needs. The [tomato soil comparison](/hub/fertiliser-soil-and-bark-mulch/tomato-soil) records the amazon.co.uk prices and specifications we compared. Before comparing brands, buy enough litres, require peat-free wording if that matters to you, check the feed window, and only then decide whether a tomato-specific name adds value. A qualifying purchase can earn us a commission at no extra cost to you.

You can stand in front of three sacks that all mention vegetables and still not know which one will fill your tomato pot.

Our top picks

UK GROW UK GROW tomato compost 10 litres

Best overall

UK GROW UK GROW tomato compost 10 litres
9.6/10about £11.99
View offer
Munnie Munnie multi-purpose compost 60 litres

Preis-Tipp

Munnie Munnie multi-purpose compost 60 litres
9.2/10about £9.34
View offer
Miracle-Gro Miracle-Gro peat-free compost 20 litres

Alternative

Miracle-Gro Miracle-Gro peat-free compost 20 litres
9.0/10about £7.95
View offer
On this page
  1. 1.What you are actually buying
  2. 2.How many litres for your plants
  3. 3.Peat-free, feed weeks and words that do not count
  4. 4.What to do next

What you are actually buying

A tomato planter is a container and compost in one. You grow directly in it, following that brand's drainage instructions. A small bag labelled tomato compost is only the growing medium. Its name says nothing about whether there is enough for a mature plant. In this comparison, UK GROW offers 2, 5 and 10 litre packs. The 10 litre bag was £11.99 and reviewers said it did not fill a large pot, while all three listings showed a conflicting 1,000 ml unit-count field. Treat the volume on the delivered sack as the evidence that matters. The RHS accepts peat-free loam-based or multi-purpose compost, so a tomato formula is not compulsory. A 20 litre Miracle-Gro bag says peat-free and includes feed for up to three months, though it needs a pot.

How many litres for your plants

Which? advises at least 10 litres of compost per tomato plant. The RHS recommends one tomato in a 30–45 cm pot and two in a standard growing bag, without defining that bag in litres. Gardeners' World gives a roomier example: two plants in 60 litres or three in 75 litres. For two plants, the 30 litre 2you planter gives 15 litres each, clearing the 10 litre floor but only half the 60 litre example. The grow bag versus pot guide helps you choose the format before you calculate the total. UK GROW's packs in this comparison were about £4 per litre for 2 litres, £2 per litre for 5 litres and £1.20 per litre for 10 litres. The 60 litre Munnie listing was £9.34, although its two-pack field leaves the delivered volume uncertain.
UK GROW UK GROW tomato compost 10 litres

Testsieger

UK GROW UK GROW tomato compost 10 litres
9.6/10about £11.99
View offer

Peat-free, feed weeks and words that do not count

If you want peat-free compost, require those exact words on the listing and delivered sack. Organic materials, natural and reduces peat use are not equivalent. Munnie's listing discusses peat reduction but does not say peat-free. A customer review calling Laeto peat-free is not a manufacturer specification. In this comparison, Miracle-Gro 20 litres and the 2you 30 litre grow bag explicitly say peat-free. The 2you planter says feed for up to six weeks; Miracle-Gro says up to three months. UK GROW, Munnie, Laeto, TerraGrade and DIVCHI do not state a feed window. UK GROW names orchid bark, perlite and vermiculite; 2you names coir, wood fibre and plant fibre. Missing listing data is n/a, not proof an ingredient is absent. The UK GROW volume mismatch, Munnie's unresolved two-pack field and the identical 1,857-review count on both Laeto sizes are not independent facts. Our peat-free tomato compost guide explains the wording and sourcing marks.

What to do next

Write down plant count and format before you return to the table. For one 30–45 cm pot, 20 litres is more forgiving than the 10 litre floor. For two plants, compare a substantial planter with compost plus two pots. Then ask whether the product explicitly says peat-free, and whether it states a feed period. Do not infer either. The best tomato grow bag guide makes conditioned picks. This buying guide does not crown a winner.

Common questions

Do tomatoes need special compost?
No. The RHS allows peat-free loam-based or multi-purpose compost for container tomatoes. A tomato-specific product may offer a convenient feed package or planter format, but the name is optional. Enough volume, suitable structure, clear peat wording and a usable feeding plan are more important.
How many litres of compost does one tomato need?
Which? gives at least 10 litres per plant. Treat that as a minimum, because a larger container usually holds moisture more steadily. The RHS recommends one plant in a 30–45 cm pot, while Gardeners' World uses 60 litres for two grow-bag plants.
Is a 10 litre tomato bag enough?
It reaches the cited minimum for one plant but leaves little margin and may not fill the recommended pot diameter. In this comparison, reviewers said the UK GROW 10 litre bag did not fill a large pot. It is better suited to a modest container or top-up than two plants.
What is John Innes No. 3 for?
John Innes No. 3 is a loam-based type intended for mature plants and can add weight and buffering to a container. The name does not guarantee a fixed legal recipe or peat-free composition. Check the individual sack for peat-free wording and manufacturer instructions.
Does tomato compost have to say peat-free?
Only if peat-free composition is part of your buying requirement. Peat compost remains legal in the UK, so you cannot assume every current sack has changed. Organic, sustainable or a peat-reduction claim does not replace the exact words peat-free.
How long should included feed last?
There is no universal target. Claims in this comparison range from six weeks on the 2you planter to up to three months on Miracle-Gro. Use the stated period to plan, but follow the delivered label and the plant's stage before adding liquid tomato feed.

Related pages

Tomato fertiliser compared

Tomato soil

Best Tomato Grow Bag UK: A Top Pick With Conditions

Tomato Grow Bag vs Pot: Volume, Watering and Depth

How to Plant Tomatoes in a Grow Bag: Drainage First

Peat-Free Tomato Compost: What the UK Label Must Say

Sources

Public UK sources used for this comparison; listings checked on amazon.co.uk. Last accessed 15 October 2026.

  1. RHS: How to grow tomatoes (retrieved 15 October 2026)
  2. RHS: Peat-free compost (retrieved 15 October 2026)
  3. RHS: Tomato blight (retrieved 15 October 2026)
  4. RHS: John Innes compost (retrieved 15 October 2026)
  5. RHS: Minimising health risks in the garden (retrieved 15 October 2026)
  6. Which?: How to grow tomatoes (retrieved 15 October 2026)
  7. Gardeners' World: tomatoes in a growing bag (retrieved 15 October 2026)
  8. Peat-Free Partnership: legislation timeline (retrieved 15 October 2026)