Perlite vs Vermiculite: What They Are and When to Use Each
Perlite and vermiculite are the two lightweight minerals growers mix into soil, coco and seed compost, and they do different jobs. Perlite lets water drain and air in; vermiculite holds water and feed. This guide explains what each one is, when to use which, and which of the soils and mixes we sell already have perlite in them.
What is perlite?
Perlite is volcanic glass that has been heated until it puffs up into light, white granules. Each granule is rigid and full of tiny air pockets, so it keeps its shape in the pot and holds the mix open around the roots.
Our Perlite page describes it as inorganic, inert and sterile, and free from disease and insects.
What is vermiculite?
Vermiculite is a natural mineral that comes from mica rock. Heated, it opens out into soft, golden-brown flakes made of thin layers, and those layers give it a very large surface area.
That surface is why, as our Vermiculite page says, it can hold many times its own weight in water. We stock the V3 (medium grain) grade, which the page describes as inert, rot-proof and odourless.
Perlite vs vermiculite at a glance
| Compare | Perlite | Vermiculite |
|---|---|---|
| What it is | Expanded volcanic glass | A natural mineral from mica rock |
| Water | Holds some water, but less than vermiculite; does not go soggy | Holds many times its own weight in water |
| Air | Aerated structure that gets plenty of oxygen to the roots | Lets plenty of oxygen through when mixed 50/50 with perlite |
| Feed | Inert - no feed of its own | Inert too, but keeps nutrients around the root zone |
| Compaction | Compacts less than vermiculite | Compacts more than perlite |
| Suggested use | An additive to improve aeration, or a medium in its own right | In a mix, for propagation |
Both pages give the same recipe: a 50/50 mix is a popular ratio that holds moisture while still letting plenty of oxygen reach the roots. You will find both under soil amendments in our growing media range: 10 L for seed trays and a few pots, 100 L for whole bags of soil or coco.
Soils and mixes that already contain perlite
Before you buy a bag to mix in, check what you are growing in. Several of the soils and one of the coco mixes we sell already have perlite in the recipe.
| Product | What is in it | Good to know |
|---|---|---|
| Jiffy Pro7 70/30 Coco Perlite Mix | 70% buffered coco coir, 30% perlite | 50 L. Pre-buffered and washed, ready to use |
| Plug Life 80/20 Peat Mix | 80% peat, 20% perlite | Tray of 104 plugs for seeds and cuttings |
| Biobizz Light Mix | Peat moss, sphagnum peat and perlite | 50 L. Great drainage and aeration, the page says |
| Biobizz All Mix | Peat moss, sphagnum peat, worm castings, perlite, mycorrhizae and Pre-Mix | 50 L. Medium to heavily pre-fertilised |
| Plagron Light Mix | Lightly fertilised organic soil mixed with perlite | The perlite is there to stop the soil compacting as much |
| Canna Terra Professional | Upgraded black peat, granulated peat moss and perlite | Nitrogen-rich and pH-adjusted |
| Gold Label Special Mix Gold | Swedish white peat, perlite and coco coir | 45 L. Pre-fertilised |
If yours is in the table, try it as it comes before you add more. For coco mixes, see the coco coir guide.
Which should I use?
- Sowing seeds: vermiculite. Gardeners commonly cover seed with a thin layer of it instead of compost, because it stays evenly moist around the seed. Or sow straight into ready-made plugs and starter cubes.
- Rooting cuttings: both together. The Vermiculite page calls a vermiculite mix ideal for propagation, and blending it with perlite gives a cutting moisture and air at the same time. Plug Life plugs are the ready-made alternative. More in propagators and cuttings.
- Soil or coco that stays wet: perlite. Mix it through before you pot up if pots take too long to dry or the mix packs down; it will not fix watering too often. The ready-made mixes show how much makers use: 30% in the Jiffy coco mix, 20% in the Plug Life plugs.
- Pots that dry out too fast: vermiculite. A little in a free-draining mix holds more water and feed between waterings.
- Growing in perlite alone: the Perlite page says it works as a medium in its own right, but all the food then has to come from a hydroponic nutrient. Canna Hydro, made for run-to-waste systems, says it is also suitable for perlite; VitaLink Hydro MAX, for recirculating and run-to-waste systems, lists perlite alongside clay pebbles and stone wool.
- Dripper systems: clay pebbles rather than either. Our Origin dripper kits such as the Origin System Small take most media, but we recommend clay pebbles, which simplify the set-up - see clay pebbles and rockwool.
Handling tips
- Keep the dust down. Dampen dry perlite in the bag before you pour it, so you do not breathe the dust in. The Vermiculite page also says to avoid inhaling the dust.
- Rinse perlite for hydroponics. Growers commonly rinse it before it goes into a hydroponic system, to wash out the fine dust that can block pumps and drippers.
- Expect perlite to float. Heavy watering can lift it to the top of the pot, which is normal; water gently. For the same reason, growers generally avoid perlite on its own in flood and drain.
- Go easy on vermiculite. It is soft and compacts more than perlite, so do not press it down hard when you fill pots or trays.
Quick answers
Is perlite the same as vermiculite?
No. Perlite is white, gritty expanded volcanic glass, added for drainage and air. Vermiculite is a soft, flaky mineral from mica rock, added to hold water and nutrients.
Perlite or vermiculite for seeds and cuttings?
Vermiculite for covering seed, and a perlite and vermiculite mix for cuttings - both product pages give 50/50 as a popular ratio.
Do I need to add perlite to coco?
No. Coco made for growing already holds plenty of air on its own. If you want it to drain faster, the Jiffy Pro7 70/30 mix has perlite blended in - our coco coir guide covers when that helps.
Do perlite and vermiculite feed the plant?
No. Their product pages describe both as inert, so the food comes from the soil they are mixed into or from the nutrient you water with. In perlite alone, keep an eye on pH and EC - see our pH and EC guide.
More Growers' Guides
Not sure what you need? Call the shop on 0117 971 3000 or pop in to the Bristol store and we'll help you pick.