Horticultural Perlite | 1 L & 5 L Bags

Perlite is the unsung hero of modern mushroom cultivation. This volcanic glass, expanded by heat into a lightweight white granule, holds water on its surface and traps air in its pores — exactly what mycelium needs in a casing layer or fruiting chamber. Our horticultural-grade perlite is screened, dust-controlled and ready to use.

Product specifications

• Available sizes: 1 L and 5 L bags
• Grade: horticultural grade, screened
• Composition: 100% expanded perlite (volcanic glass)
• pH: neutral (6.5–7.5)
• Properties: sterile by nature, lightweight, water-retentive, highly aerative

Three key uses in mushroom cultivation

Perlite serves three distinct roles for the mycologist:

1. Humidity reservoir — at the bottom of a Shotgun Fruiting Chamber (SGFC) or monotub, a 4–5 cm layer of wet perlite slowly releases moisture and keeps humidity around 90–95%
2. Casing layer — mixed with vermiculite or coir on top of colonised substrate, perlite improves gas exchange and pinning consistency
3. Bulk substrate amendment — added to CVG or coir mixes (10–20% by volume) for extra aeration on dense, water-heavy substrates

How to use perlite as a humidity reservoir

1. Pre-soak — submerge the perlite in clean water for a few minutes
2. Drain — pour into a colander and let surface water drip off (no standing water in the chamber)
3. Layer — spread an even 4–5 cm layer at the bottom of your fruiting chamber
4. Monitor — top up with a hand mister every 1–2 days as the perlite dries out

Which mushrooms benefit

Perlite supports virtually every cultivated mushroom species:

• Psilocybe cubensis — all strains, in monotub and shotgun chamber setups
• Pleurotus ostreatus — oyster mushroom, in humidity chambers
• Hericium erinaceus — lion's mane, for casing layers
• Stropharia rugosoannulata — wine cap, for bulk substrate amendment
• Lentinula edodes — shiitake, in fruiting chambers after pinning

Safety note

Always wet perlite before handling — dry perlite produces fine dust that can irritate the lungs. Wear a dust mask when opening a fresh bag, and rinse the perlite under running water before use. Once damp, it's completely safe to handle.

Pair with the rest of your kit

Build a complete bulk substrate with perlite as your aeration component: Sterile CVG Substrate Mix and Vermiculite Grade 3 .

Storage

Store unopened bags in a dry place, away from direct sunlight. Perlite has an indefinite shelf life when kept dry.