Perlite

Why perlite goes in the mix

Oxygen at the roots

When a potting mix packs down, the oxygen supply stops — and roots need that air as much as they need water. Perlite begins as volcanic glass. Heat it to roughly 850-900°C and it pops, swelling to as much as 20 times its original volume, leaving rigid, porous granules that hold their shape indefinitely. Blend those granules through soil or coco and they keep the medium from compacting, leave air pockets around the roots and give them room to respire. Mixes rich in perlite therefore carry a lower risk of root rot.

Faster drain, still some moisture

Call it more than a drainage chip. Perlite holds enough moisture to work as a hand-watered medium, yet still clears water fast enough for a recirculating drip system. Put it in the mix and water leaves the pot sooner, without the medium going bone dry between waterings. That is the same balance that puts it in so many ready-made potting mixes — Canna Terra Professional included.

The perlite range on this page

Loose grades

The shelf holds two grades. Coarse 4mm-6mm comes as a 10L bag and is the general-purpose choice for mixing through soil, coco or a seed-raising mix. Extra-coarse 8mm-12mm comes as a 100L bag for larger pots and beds, where the bigger granules keep the structure open under more weight. A 20L Exfoliators Hydro-Perl grow bag sits beside them, made to be planted into directly — it takes roughly 10.5L of water to saturate, against up to 15L for a traditional grow bag.

Ready-mixed 70/30 coco

Prefer not to mix your own? Coco perlite is stocked at the standard 70/30 ratio in a 10L Grow Kings bag and a 53L Green Planet bag — both RHP certified, washed, pre-buffered with calcium and magnesium, and pH stabilised. The Grow Kings Premium Indoor Plant Blend adds coco chips to the same idea for aroids and other indoor foliage. Canna Terra Professional is a peat-based potting mix that already has perlite through it.

How to pick perlite

1. Loose or pre-blended. Buy loose perlite when you already have a base medium and want to set the ratio yourself. Buy a 70/30 coco perlite blend when you want a ready-to-plant substrate with the mix already done.
2. Grade to the pot. Finer 4mm-6mm perlite suits seed-raising mixes, small pots and anything you hand water. Extra-coarse 8mm-12mm suits large containers and beds, where finer grades settle over a long crop.
3. Bag to the job. A 10L bag amends a few pots. A 100L bag is for filling beds or mixing a season's worth of substrate in one go, and it ships as a bulky item.
4. Match how you water. Mixes heavy in perlite drain fast and want more frequent, smaller waterings; heavier blends hold longer between them.

How watering works with perlite

Water moves through perlite by capillary action. Nutrient solution is drawn up from a reservoir through the granules at roughly the rate the plant is using it. That is why it suits bottom-fed, tray and auto-watering setups, and why a perlite-rich medium is more forgiving of both over- and under-watering than a dense one. The top of a perlite blend can look dry while the root zone is still moist, so judge by pot weight or a probe, not by how the surface looks.

Perlite lives with the store's other grow mediums. If you want a medium that holds water rather than shedding it, go to vermiculite. If you want a reusable inert aggregate built for hydroponic systems, go to LECA clay balls.