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Vermiculite vs perlite

Updated: October 2026

Vermiculite vs perlite comes up when two pale bags look alike, or when a maidenhair fern and a cactus need different compost on the same Saturday. Vermiculite holds water. Perlite lets surplus water leave. Grit is the third choice when drainage is the whole job. The packs, including one ready-made blend, are on the [vermiculite for plants comparison](/hub/ornamental-plants/vermiculite-for-plants). The Products Compared editorial team did not run a mixing trial. The split follows Gardeners' World, RHS houseplant notes and the British Cactus and Succulent Society, with listings dated 15 October 2026. A qualifying purchase can earn a commission at no extra cost to you.

Vermiculite vs perlite comes up when two pale bags look alike, or when a maidenhair fern and a cactus need different compost on the same Saturday. Vermiculite holds water. Perlite lets surplus water leave.

Our top picks

PLANT!T PLANT!T vermiculite 100 L

Best overall

PLANT!T PLANT!T vermiculite 100 L
8.8/10about £42.95
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UK GROW UK GROW vermiculite bag 25 L

Best value

UK GROW UK GROW vermiculite bag 25 L
8.0/10about £19.99
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B2C B2C 50/50 perlite and vermiculite 100 L

Alternative

B2C B2C 50/50 perlite and vermiculite 100 L
4.2/10about £32.49
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On this page
  1. 1.The sponge and the aerator
  2. 2.Houseplants, seed and succulents
  3. 3.Buying a mix instead of two bags

The sponge and the aerator

Gardeners' World states the contrast directly: vermiculite holds water, perlite aerates, and if you use both you put perlite in the mix and vermiculite on top. Neither mineral is a fertiliser. Published water-holding claims for vermiculite run from about three to six times the flake's weight. Perlite does not replace vermiculite when the compost must stay damp. In a 4 L pot of peat-free compost for a Calathea, 1 L of vermiculite leans the mix towards moisture, and the same litre of perlite leans it towards air.

Houseplants, seed and succulents

For a fern or a Calathea that collapses when the compost dries, vermiculite is the mineral the RHS points at. Pennells uses about half vermiculite for maidenhair fern, which is a high share and will stay wet if you water heavily in a cool week. For ordinary potting on, Westland's 25–30 per cent is the more cautious band. The jug method for that share is on the how to use vermiculite for plants page. For seed, Gardeners' World puts perlite in the compost and vermiculite on the surface. The surface layer slows drying and is described as some help against damping off, which is not a fungicide and not a reason to bury seed that needs light. Depths sit on the vermiculite for seed sowing page. Fine vermiculite makes the thin cover. Medium perlite in the mix does not, however similar the bags look. For a cactus, leave the vermiculite closed. The British Cactus and Succulent Society uses John Innes No. 2 or No. 3 with grit, coarse sand or perlite in about equal parts, and more grit for drier species.
PLANT!T PLANT!T vermiculite 100 L

Testsieger

PLANT!T PLANT!T vermiculite 100 L
8.8/10about £42.95
View offer

Buying a mix instead of two bags

One listing here is already the blend. B2C Pervermix, ASIN B0HF89B1VH, is 100 L of half perlite and half vermiculite, graded 1–8 mm, at £32.49, about 32 pence per litre of mix. It is sold by litres, the extract has no review line, and the item weight is unstated. A 1–8 mm span is not a fine seed cover. You cannot call the bag pure vermiculite, and the low rate is not the best value for vermiculite on the best vermiculite for plants page. The blend fits young plants if you wanted both minerals and you accept that nobody in the extract has described the fill or the balance. It is a poor cactus compost and a poor 2 mm seed cover. Use vermiculite when the compost must stay moist, perlite or grit when it must drain, and both only when you want air in the mix and a moister surface. If you are unsure, mix a 1 L pot each way and water them on the same morning. The pot still wet on day four is the one that received the sponge.

Common questions

Which one holds water?
Vermiculite holds water, and perlite is there so air and surplus water can move. Gardeners' World states that split, with perlite in the mix and vermiculite on top if you want both. A four-times water claim appears in that guidance and on one UK GROW seller line. It is not a figure for every brand, and a 16-times claim is not one to use.
Which mineral suits a fern or a Calathea?
Vermiculite, because those plants suffer when the compost dries. The RHS points it at houseplants that dislike drying out, and Pennells uses about half vermiculite for maidenhair fern. That half-share is wetter than Westland's 25–30 per cent for ordinary potting on. You still need compost and feed around the mineral. If the room is already humid and the pot never dries, cut the share.
Which one should I use for a cactus?
Use grit, coarse sand or perlite, not vermiculite. The British Cactus and Succulent Society mixes John Innes No. 2 or No. 3 with one of those in about equal parts, and uses more grit for drier species. Emsworth suggests about a handful of grit or perlite per litre. The RHS prefers grit when drainage is the only goal, so a review that put vermiculite on cacti is not a reason to copy it.
Can I use vermiculite and perlite together?
Yes, when you want air in the compost and a moister surface. Put perlite in the mix and a vermiculite cover on seed, which is the Gardeners' World pattern. A ready-made half-and-half bag does both jobs in one sack, and the B2C listing is graded 1–8 mm. Do not treat that blend as pure vermiculite. If the plant is a succulent, skip the vermiculite half.
Is grit a third option?
Yes. For succulents and alpines, grit is often the clearer drainage material. The British Cactus and Succulent Society lists it beside coarse sand and perlite, and RHS notes prefer grit to perlite when drainage is the only job. Vermiculite is not in that drainage list. Use grit for sharp drainage, perlite for a lighter mix, and vermiculite when drying out is the problem.

Related pages

Horticultural vermiculite buying guide

Vermiculite for plants

Best vermiculite for plants: the top pick and value

How to use vermiculite for plants in UK compost mixes

Vermiculite for seed sowing: depth, grit and cover

Sources

Public sources used for this comparison. Prices are amazon.co.uk shelf prices from the listing extracts dated 15 October 2026.

  1. RHS seed germination guide (retrieved 15 October 2026)
  2. RHS peat-free advice (retrieved 15 October 2026)
  3. RHS houseplant growing media (retrieved 15 October 2026)
  4. BBC Gardeners' World: how to use vermiculite (retrieved 15 October 2026)
  5. Westland Gro-Sure vermiculite (retrieved 15 October 2026)
  6. HSE COSHH basics (retrieved 15 October 2026)
  7. HSE EH44 dust guidance (retrieved 15 October 2026)
  8. US EPA: horticultural vermiculite in potting soil (retrieved 15 October 2026)
  9. Summit Environmental (UK): vermiculite insulation versus horticultural bags (retrieved 15 October 2026)