For potting soil that stays wet for days and packs down hard around the roots, which is where root rot usually starts. Perlite is the simplest fix: light white granules that open up the mix, let water drain through and keep air around the roots. This one is sifted to take out most of the fine dust, so it's far less messy to mix indoors. 2–6mm grain. 3L resealable bag.
Perlite is volcanic glass that has been heated until it pops, a little like popcorn, into light, porous grains. It doesn't rot or break down, so the air pockets it makes in a pot last for years, long after bark or coir have softened. In a dim Irish winter, when plants drink slowly and compost stays damp, that extra airflow makes a real difference. It holds a little water on its surface but lets the rest run through. That makes it the opposite of vermiculite, which soaks water up and holds it.
Which plants it suits
Most everyday houseplants, from Monstera and pothos to spider plants, and anything that dislikes sitting wet: succulents, cacti, hoyas and many aroids. For plants that like to stay evenly damp, such as Calathea, Maranta and Alocasia, use vermiculite instead, or a mix of the two.
How to use
- To lighten a mix: stir in roughly one part perlite to three or four parts potting soil, or more for plants that want to dry out quickly.
- To build your own: blend it with our Base Soil Mix, along with bark or coconut husk for thick-rooted plants.
- For cuttings: root them in a pot of damp perlite, or in a jar of water and perlite.
- Pour it gently and work somewhere with good air. Sifted perlite throws up far less dust, but not none.
At a glance
| What it is | Horticultural perlite, sifted |
| Grain size | 2–6mm |
| Origin | Greece |
| pH | 6.5–7.5 (neutral) |
| Water holding | Low, about 35–45% |
| Lasts | Years; it doesn't break down |
| Volume | 3 litres, resealable bag |
- Suitable for organic growing.
- Can be harmful if eaten. Keep it out of reach of pets and children.