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Houseplant potting mix UK for one or two indoor pots

Updated: October 2026

The peace lily has split its pot, the hallway will not take a 14 kg sack, and every 60 litre listing still says indoor plants. Houseplant potting mix UK shoppers should start from bag size and drainage, not from a patio title that mentions houseplants. An 8 to 10 litre indoor mix is the default. A 60 litre multi-purpose sack is a patio product. This page is the indoor use-case for the bags in the [potting soil comparison](/hub/fertiliser-soil-and-bark-mulch/potting-soil). The Products Compared editorial team used RHS houseplant notes, Gardeners' World, Which? and the listings. We did not repot the plants. A qualifying purchase can earn a commission at no extra cost to you.

The peace lily has split its pot, the hallway will not take a 14 kg sack, and every 60 litre listing still says indoor plants.

Our top picks

Focus Houseplant Focus peat-free mix 2 x 8 L

Best overall

Focus Houseplant Focus peat-free mix 2 x 8 L
9.2/10about £17.98
View offer
Miracle-Gro Miracle-Gro houseplant potting mix 10 L

Alternative

Miracle-Gro Miracle-Gro houseplant potting mix 10 L
8.6/10about £8.99
View offer
PLANT!T PLANT!T compressed coir 15 L

Alternative

PLANT!T PLANT!T compressed coir 15 L
8.6/10about £9.86
View offer
On this page
  1. 1.Indoor mix or multi-purpose sack
  2. 2.The indoor bags in this comparison
  3. 3.Fungus gnats and smell after repotting
  4. 4.When a large sack is still the right buy

Indoor mix or multi-purpose sack

The RHS treats a dedicated indoor mix as a real product. None of these nine bags is a cactus or orchid mix. For a leafy houseplant, judge bag size and how wet the mix stays. Miracle-Gro is 10 litres and 3.34 kg at about £8.99. Houseplant Focus is two 8 litre bags at about £17.98. DIVCHI and PLANT!T are bricks. A Growmoor or Munnie sack is about 14 to 15 kg and will sit in a hallway if you only needed one small pot. A coarse sack with no drainage holes stays wet, which is where gnat larvae live. The named picks are on best potting compost.

The indoor bags in this comparison

Miracle-Gro 10 litres is the high-sample indoor bag: about £8.99, 4.3 from 4,661 reviews, with a feed claim of up to three months. It does not print peat-free. Reviews mention fungus gnats, smell and a coarse texture. Houseplant Focus prints peat-free: about £17.98, about £1.12 a litre, 4.6 from 1,739 reviews, and a repot every 18 to 24 months. The listed 1.2 kg does not match 16 litres. Some reviewers add perlite or orchid bark. DIVCHI at about £7.70 is a 680 g block with no peat-free line. PLANT!T at about £9.86 expands to a claimed 15 litres and says nothing added. The Miracle-Gro twin at about £12.30 has 274 reviews and notes of sticks, plastic and gnats.
Focus Houseplant Focus peat-free mix 2 x 8 L

Testsieger

Focus Houseplant Focus peat-free mix 2 x 8 L
9.2/10about £17.98
View offer

Fungus gnats and smell after repotting

Fungus gnats show up on Miracle-Gro's houseplant mix and the twin pack. The RHS links them to damp compost. Gardeners' World says let the surface dry and add about 1 cm of grit. Which? says keep bags closed. No listing here is sold as sterile, and this page will not invent a microwave step. The finger test is on how to use potting compost. Laeto's farmyard smell is why reviewers skip that 120 litre sack indoors, even though the bullets name houseplants. Growmoor and Munnie can fill many pots if you can store the bag. They are a poor first buy for one plant in a flat.

When a large sack is still the right buy

A 60 litre sack fits if you are potting many indoor plants and can keep the rest outside. Growmoor at about £13.98, 14 kg, 4.5 from 7,425 reviews, is the sack whose litres and weight agree. Munnie at about £9.34 is cheaper on the title, with a pack-count clash. Laeto states 120 litres, and at least one review describes 40 litre bags. Skip Growmoor 2 x 60 L at about £21.71 if you need that brand every time. Substitute Bayview bags appear in the reviews. For one or two plants, stay with Miracle-Gro 10 litres or Houseplant Focus. The printed peat-free faces are Houseplant Focus and PLANT!T.

Common questions

Can I use multi-purpose compost for houseplants?
Yes, if the pot drains and you water by feel. A dedicated 8 to 10 litre indoor mix is still the better default in a flat, because the sack is smaller and the texture is usually finer. A 14 kg 60 litre sack is a patio product that happens to mention indoor plants on the title.
Which bag in this set is for indoor plants?
Miracle-Gro's 10 litre houseplant mix and Houseplant Focus's two 8 litre peat-free bags are the indoor-sized faces. DIVCHI and PLANT!T are compressed bricks you can use indoors after you add water. Growmoor, Munnie and Laeto are patio-scale sacks.
Why do I get fungus gnats after repotting?
Larvae live in wet compost. Fresh bags, peat-free mixes, and overwatering all raise the risk. The RHS and Gardeners' World tell you to let the surface dry and to keep bags closed. No listing here claims a sterile mix. Miracle-Gro's indoor reviews are where that complaint shows up in this set.
Is Houseplant Focus peat-free?
Yes. The title, item type and bullets print peat-free. It is two 8 litre bags at about £17.98. Adding perlite or orchid bark, as some reviewers do, does not change that line.
Should I add perlite or bark?
Only if the plant needs a more open mix than the bag already is. Houseplant Focus reviewers add perlite and orchid bark for tropical plants. The listing does not include them. Cactus and orchid structures are still a different purchase.
Is a 60 L sack sensible for a flat?
Usually not, if you have one or two plants and no shed. Growmoor's 60 litre sack is 14 kg. Munnie is 14.9 kg with a pack field that says 2. Buy the 10 litre bag or a brick unless you are potting many plants and can store the rest outdoors.
Does Miracle-Gro houseplant mix contain peat?
The listing does not print peat-free. The RHS rule is that a bag which does not say peat-free most likely is not. Do not treat the houseplant title as a peat-free claim.

Related pages

Peat-free potting compost

Potting soil

Best potting compost UK for patio pots or indoor use

How to choose potting compost for pots and baskets

How to use potting compost in pots and coir bricks

Sources

Public UK sources from the research digest, used for this page in October 2026. Prices, stars and review counts are from the nine amazon.co.uk listings captured on 21 October 2026. Peat-free means the listing prints those words. Organic wording is not a certificate. This page did not measure fill volume or run a growth trial.

  1. RHS, peat-free choices (retrieved 21 October 2026)
  2. RHS, how to plant a container (retrieved 21 October 2026)
  3. RHS, minimising health risks in the garden (retrieved 21 October 2026)
  4. RHS, retail peat-free from 2026 (retrieved 21 October 2026)
  5. Which?, best compost 2026 (retrieved 21 October 2026)
  6. Which?, peat-free compost for patio pots (retrieved 21 October 2026)
  7. GOV.UK, sale of horticultural peat (retrieved 21 October 2026)
  8. Garden Organic, garden compost or potting compost (retrieved 21 October 2026)