Independent comparisons. We may earn from shop links. More info

Citrus compost vs multipurpose for potted lemons

Updated: October 2026

You already have a multipurpose bag in the shed, and the lemon on the patio looks fine until you read that citrus need something special. The honest UK answer is that a general-purpose compost is built for seed trays and borders, not for a woody plant in a pot that must survive wet winters. A dedicated citrus mix, or a peat-free John Innes No. 3 with grit, matches what the Royal Horticultural Society describes for container citrus. Multipurpose alone is the shortcut that most often ends in soggy roots. This comparison does not score bags; the eight citrus listings are on the [citrus soil](/hub/trees-and-palms/citrus-soil) page. Criteria and litres are on the [citrus compost buying guide](/hub/trees-and-palms/citrus-soil/sub/citrus-soil-buying-guide).

You already have a multipurpose bag in the shed, and the lemon on the patio looks fine until you read that citrus need something special.

Our top picks

Topline Topline Citrus Potting Mix (2 × 10 L)

Best overall

Topline Topline Citrus Potting Mix (2 × 10 L)
7.0/10about £20
View offer
Westland Westland Citrus Potting Mix (2 × 10 L)

Rank 2

Westland Westland Citrus Potting Mix (2 × 10 L)
8.8/10about £18.58
View offer
UK GROW UK GROW Citrus Potting Mix (25 L)

Best value

UK GROW UK GROW Citrus Potting Mix (25 L)
6.2/10about £22.99
View offer
On this page
  1. 1.What goes wrong with multipurpose alone
  2. 2.When a specialist citrus bag is worth it
  3. 3.John Innes No. 3 plus grit
  4. 4.Ericaceous is not the same shelf

What goes wrong with multipurpose alone

Multipurpose compost is formulated to hold moisture for a wide range of quick crops. In a large patio pot that stays outside through autumn rains, or indoors when you water on habit, that water-holding works against citrus roots, which want air as much as moisture. East of Eden’s citrus guide warns against lime-containing multipurpose for lemons; lime pushes pH upward, while container citrus are often quoted around pH 6 to 6.5, including Thompson & Morgan’s lemon-growing page. Even a peat-free multipurpose that feels light in the hand can compact and stay wet in a pot you rarely lift. For a permanent lemon, the RHS route is a peat-free loam-based compost with about 20 per cent grit, not a general bag on its own. If you only have multipurpose today, you could mix in grit and use it as a stopgap for a top-dress, but you are building a home blend that is not one of the scored rows on the main page. Winter watering mistakes with that blend are covered on indoor lemon compost, because drainage in the bag does not fix a saucer full of water.

When a specialist citrus bag is worth it

A bag labelled for citrus or citrus and olive has a stated job: free drainage, often with perlite, grit, or clay granules named on the listing. In our set, Westland states peat-free mix with Seramis and perlite. Topline states peat-free with Seramis. POT CULTURE names perlite and grit but does not state peat-free on the bullets we captured. UK GROW states a loam-based, free-draining mix without a peat-free claim. Westland’s own advice is not to use its citrus mix on ericaceous plants. A specialist bag is worth the extra when you are repotting a tree you expect to keep for years, you want the listing to name drainage ingredients, or you do not want to weigh out grit in the driveway. It is harder to justify if you only refresh the top few centimetres and already own John Innes No. 3.
Topline Topline Citrus Potting Mix (2 × 10 L)

Testsieger

Topline Topline Citrus Potting Mix (2 × 10 L)
7.0/10about £20
View offer

John Innes No. 3 plus grit

John Innes No. 3 is the traditional container mix for mature woody plants. The RHS citrus advice points to peat-free loam-based compost with grit. East of Eden suggests John Innes No. 3 with about 25 per cent drainage material. Those recipes converge on the same idea: structure and weight in the mix, with grit or perlite so water leaves the root zone. Mixing at home is often the best value if you already buy JI No. 3 for other pots. Follow the repot size limits on how to repot a lemon tree so the extra drainage is not wasted in a tub that is far too large.

Ericaceous is not the same shelf

Ericaceous compost is sold for acid-loving shrubs. Westland explicitly says not to use its citrus compost on ericaceous plants, which implies the blends sit differently on the pH scale. Garden UK, in contrast, lists ericaceous or citrus at pH 5.5 to 6.5 for citrus trees. The sources disagree. If you already opened ericaceous for a blueberry, do not pour the remainder onto a lemon without checking. When in doubt, a citrus-labelled mix or John Innes plus grit aligns with RHS container guidance more often than ericaceous alone.

Common questions

Can I use the multipurpose bag in the shed?
For a short top-dress or an emergency, mixed with plenty of grit, it may suffice. For a full repot of a long-lived lemon, it is the wrong tool on its own because it stays wet and may contain lime. Plan a citrus mix or a John Innes blend for the next proper repot.
Is ericaceous compost the same as citrus compost?
No. They are shelved near each other in some shops, but UK advice conflicts on whether ericaceous suits citrus at all. Westland’s citrus line is not for ericaceous plants. Check your bag rather than the shelf headline.
Is John Innes No. 3 enough on its own?
Often not for citrus in a pot. The RHS and several UK growers add grit or perlite, roughly 20 to 25 per cent, so water moves through. Straight No. 3 in a wet autumn can still suffocate roots if the pot is too large.
Will peat-free multipurpose work if I add grit?
Grit improves drainage but does not remove lime or turn multipurpose into a loam-based John Innes substitute. It is a workaround, not the same product as the bags in our citrus comparison.
Why was all-purpose compost not in the comparison?
Products such as Miracle-Gro all-purpose are general fertiliser composts, not specialist citrus container mixes. We kept the table to bags marketed for citrus or clear citrus/oil mixes on amazon.co.uk.

Related pages

Best citrus potting mix

Citrus soil

Citrus soil buying guide: litres, drainage, and price

How to repot a lemon tree: UK pot size and watering

Indoor lemon tree compost: UK winter water and heat

Sources

Public UK sources from the research digest, used for this page in October 2026. Prices, stars and review counts are from the amazon.co.uk listings stored on 19 October 2026. Garden-centre shelf prices are not Amazon prices. This is not a laboratory test.

  1. RHS, How to grow citrus (retrieved October 2026)
  2. RHS, Citrus problems (retrieved October 2026)
  3. RHS lemon profile (retrieved October 2026)
  4. Westland Citrus Potting Mix (retrieved October 2026)
  5. Hansard written answer, 19 March 2026 (retrieved October 2026)
  6. Responsible Sourcing Scheme (retrieved October 2026)
  7. Thompson & Morgan citrus guide (retrieved October 2026)
  8. Pennells, Westland 10 L (retrieved October 2026)