For houseplants that keep getting overwatered, roots that rot in soggy compost, and the fungus gnats that come with it. This is a soilless, peat-free mix of pumice, zeolite and lava rock that never turns to mush, stays airy around the roots, and has nothing in it for gnats to breed in. Pair it with a self-watering pot and watering stops being guesswork: you just keep an eye on the water level. Chunky 8–16mm grains for thick-rooted plants like Monstera, Philodendron and Alocasia, with about six months of plant food mixed in. It can be rinsed and reused for years. 5L resealable bag.
Potting compost has a short life indoors. It slumps and packs down around the roots, and through the dim, damp Irish winter it can stay wet for days, which is how root rot and fungus gnats get started. Stone doesn't do any of that. Each grain keeps its shape, so air moves freely through the pot, and the porous pieces hold just enough water to keep the roots going without ever turning soggy. With no organic matter in the mix, there's nothing in it to rot and nothing for fungus gnats to breed in.
What's in it
Two parts pumice, light and full of air pockets, to keep the mix open and draining. Two parts zeolite, a pale green mineral that soaks up water and nutrients and gives them back slowly. One part each of black and red lava rock, heavier, to anchor the plant and add trace minerals. A tropical slow-release plant food is mixed through, enough for around six months.
Which plants it suits
The chunky grain is for large aroids, mature houseplants and anything with thick, fleshy roots that likes a little air between waterings: Monstera, Philodendron, Alocasia, Anthurium, Ficus and Dieffenbachia. It isn't the right mix for cacti and succulents, which don't want damp roots, or for orchids, which do better in a mix made for them. Not every plant takes to growing in stone, either. A plant that has spent years in soil may take a while to settle as it grows new roots suited to stone.
How to use
- Rinse the mix before use. Some dust settles in the bag in transit, and it washes straight off.
- Clean the roots. Gently wash away as much of the old soil as you can, because any left behind can rot in the stone. Cuttings rooted in water can go straight in.
- Pot up. It works best in a self-watering pot, or a clear pot without drainage holes, where you can see the water level.
- Water differently. Keep a little water standing in the bottom of the pot, and let the stone draw it up to the roots.
- Feed after about six months. The built-in plant food lasts 120 to 180 days. After that, use a fertiliser made for mineral or semi-hydro growing. Organic, soil-based feeds aren't suited to stone.
- Reuse it. When you repot, rinse the stones and use them again.
At a glance
| Contents | Pumice, zeolite, black and red lava rock (2:2:1:1), with tropical slow-release plant food |
| Grain size | Chunky, 8–16mm |
| Volume | 5 litres, resealable bag |
| Built-in feed | Around 6 months (120–180 days) |
| Peat-free | Yes, soilless and with no organic matter |
| Reusable | Yes, rinse between uses |
| Best with | Self-watering pots, or clear pots without drainage holes |