Choosing houseplant compost or pon for indoor pots
Updated: October 2026
You are choosing between a familiar bag of organic houseplant compost and a bag of Lechuza mineral substrate that amazon.co.uk still files near compost searches. Houseplant compost or pon is a materials decision. Compost is a fibre mix you water like soil. Pon is pumice, lava, and zeolite. The [houseplants compost comparison](/hub/fertiliser-soil-and-bark-mulch/houseplants-compost) lists both. This page draws one contrast, then tells you when to stay with compost. Prices are in pounds. A qualifying purchase can earn a commission at no extra cost to you.
You are choosing between a familiar bag of organic houseplant compost and a bag of Lechuza mineral substrate that amazon.co.uk still files near compost searches. Houseplant compost or pon is a materials decision.
You are choosing between a familiar bag of organic houseplant compost and a bag of Lechuza mineral substrate that amazon.co.uk still files near compost searches. Houseplant compost or pon is a materials decision. Compost is a fibre mix you water like soil. Pon is pumice, lava, and zeolite. The houseplants compost comparison lists both. This page draws one contrast, then tells you when to stay with compost. Prices are in pounds. A qualifying purchase can earn a commission at no extra cost to you.
Our top picks
| Badge | Product | Form | Feed claim | Weight | Note | Price | Offer |
|---|---|---|---|---|---|---|---|
| Best overall |  Lechuza Lechuza Basicpon 12 L | Mineral substrate | Fertiliser-free | 10 kg | 7.9 | about £18.98 | View offer |
| Alternative |  Lechuza Lechuza-PON 18 L | Mineral substrate | Nutrients claimed; months not on this listing | 14.9 kg | 8.3 | about £23.99 | View offer |
| Best value |  Miracle-Gro Miracle-Gro houseplant mix 10 L | Houseplant bag | Up to 3 months | 3.34 kg | 7.9 | about £8.99 | View offer |
On this page
Compost and pon are different materials
An indoor compost bag is built from organic or fibre components that hold some moisture around roots. Miracle-Gro's ten-litre houseplant mix at about £8.99 weighs about 3.34 kg; Westland's eight-litre mix at about £9.47 is the other common light option for a few pots. You plant into it much as you would any potting mix, watch the surface, and water when it dries. Review themes on those organic bags include growth praise and, repeatedly, fungus gnats when the mix stays damp.
Pon is a mineral substrate. Lechuza describes pumice, lava, and zeolite for both Basicpon and LECHUZA-PON. It is sold for indoor plants, including orchids and citrus on the PON listing, and it is peat-free on these listings. The amazon item type Planter is a catalogue error: you are buying substrate, not a pot. You can use it with a reservoir or in an ordinary pot with a hole. It will not behave like coir compost.
Basicpon or Lechuza-PON
Inside the mineral fork, feed is the split that traps people. Basicpon six litres is about £14.98 and about 5.2 kg; twelve litres is about £18.98 and about ten kilograms. Both print peat-free and fertiliser-free. Lechuza positions Basicpon for sensitive plants and cuttings and for growers who will fertilise themselves. The six-litre and twelve-litre listings share 4.8 from 352 reviews and the same review text, so treat that star line as one sample.
Lechuza-PON eighteen litres is about £23.99, about 14.9 kg, with 4.7 from 5,617 reviews. It prints peat-free and claims nutrients in the root area. Lechuza's own UK pages give about six to eight months for PON, not for Basicpon. Choose PON for that feed window. Choose Basicpon only if you will feed once the plant is settled. Do not assume the cheaper Basicpon bag includes PON fertiliser.
Weight, dust, and rinsing
Mineral bags punish flats with stairs. Against Miracle-Gro's 3.34 kg ten-litre compost bag, Basicpon twelve litres at about ten kilograms and PON eighteen litres at about 14.9 kg are a different lift. Order a size you can carry and store dry. Dust is a recurring handling point: reviewers rinse pon before use, and Lechuza's declaration discusses dust and gloves. Open the bag away from your face, and wash your hands after.
A rinse in a colander reduces fines and cloudiness before the first watering. For pot width and when to water after the move, use how to repot houseplants.
When to stay with compost
Stay with an eight- to ten-litre indoor compost bag if you want a light purchase, a familiar watering feel, and a few ordinary foliage plants rather than a semi-hydro project. Westland and Miracle-Gro cover that job at entry prices. Houseplant Focus covers it when the bag must say peat-free. Fungus gnats are a reason people switch to mineral mix because damp organic compost is where those flies breed, and RHS advice includes fresher medium and careful watering as controls. That is not proof that every compost bag is infested, and it is not proof that pon cannot support fungus if you keep a reservoir permanently sodden or leave algae and debris in place.
Skip pon if you cannot lift ten to fifteen kilograms or expected a soft soil look. Skip Basicpon if you thought fertiliser was included. Skip a large multi-purpose sack when the job is one bedroom plant. Format choice belongs in the houseplant compost buying guide.
Use compost for light indoor potting, Lechuza-PON for mineral structure with the manufacturer's feed window, and Basicpon when you will feed yourself. If you are unsure, buy the smaller compost bag first.
Common questions
Is pon a kind of compost?
No. Compost here means an organic or fibre potting mix. Pon is a mineral substrate of pumice, lava, and zeolite. Search results mix them; the materials do not.
What is the difference between Basicpon and Lechuza-PON?
Basicpon is fertiliser-free. PON includes slow-release nutrients with a manufacturer window of about six to eight months. Minerals are otherwise in the same family. Prices and bag sizes differ on the listings.
Do I have to rinse it?
Many users rinse to reduce dust and fines before planting. Follow the pack and declaration. Gloves appear in manufacturer handling notes for dusty mineral media.
Will it stop fungus gnats?
Mineral mix removes the organic compost layer gnats prefer, which is why people switch. It is not a sterilisation guarantee if watering stays permanently wet. Compost gnats are also managed by drying cycles and hygiene, not only by changing brand.
Can I use it in a normal pot?
Yes, if the pot drains and you learn the drying time. Semi-hydro reservoirs are optional, not mandatory. Do not leave the roots sitting in stagnant water without a plan.
How heavy is the bag?
About 5.2 kg for Basicpon six litres, about ten kilograms for twelve litres, and about 14.9 kg for eighteen-litre PON, versus roughly 3.34 kg for Miracle-Gro's ten-litre compost bag.
Is it peat-free?
These Basicpon and Lechuza-PON listings print peat-free. Confirm on the bag you receive.
When do I start feeding Basicpon?
Once the plant is settled, because Basicpon is sold fertiliser-free. Do not wait for PON's six-to-eight-month window; that applies to PON, not Basicpon.
Related pages
Sources
Public UK sources from the research digest, used for this page on 23 October 2026. Prices, stars and review counts are from the stored amazon.co.uk listings. A peat-free line is only what that listing prints. This is not a laboratory test.
- RHS, peat-free compost (retrieved 23 October 2026)
- RHS, peat-free retail from 2026 (retrieved 23 October 2026)
- Defra, horticultural peat announcement, 27 August 2022 (retrieved 23 October 2026)
- Hansard written answer, 19 March 2026 (retrieved 23 October 2026)
- Consumer Rights Act 2015, section 11 (retrieved 23 October 2026)
- RHS, fungus gnats (retrieved 23 October 2026)
- RHS, growing houseplants (retrieved 23 October 2026)
- RHS, health risks in the garden (retrieved 23 October 2026)