Plagron Perlite — RHP-Certified Volcanic Aeration Medium for Soil & Hydroponics
Best for: Growers wanting to improve drainage, aeration, and root development without overcomplicating their substrate mix
Our thoughts
Perlite is one of those unglamorous bits of kit that quietly does the heavy lifting in any growing setup. Plagron's version is RHP certified, sterile, and properly consistent — you're not guessing whether your medium's going to drain or clog. It's the foundation of half the good mixes out there, and at this price point, there's no reason to cheap out.
Plagron Perlite is a 100% volcanic glass medium used to improve soil structure, drainage, and root aeration across soil-based and hydroponic growing setups. Naturally sterile, neutral pH, and free from contaminants, it works as either a substrate additive (typically 10–35% of your mix) or a standalone hydroponic medium. The result: better water/air balance, stronger root development, and the kind of consistent performance you can actually rely on.
How it compares
Perlite sits at the budget-friendly end of aeration media, but don't mistake that for cheap.
- Significantly lower cost than expanded clay (hydroton) — roughly half the price for equivalent coverage
- Superior drainage and capillarity compared to rockwool — less waterlogging, better root oxygenation
- Reusable and sustainable; can be cleaned and reused across cycles
- RHP certified — same assurance you get from premium substrate brands
In plain terms: you're getting Dutch-made quality at a price that leaves money for nutrients and lighting.
Usage guidance
Perlite is genuinely versatile. How you use it depends on your setup.
Soil amendment
Mix perlite at 10–20% of your substrate volume to improve drainage in dense soils. Works particularly well lightening heavy compacted mixes or improving runoff in container growing.
Mixed media substrates
Combine with coco coir (70/30 coco-to-perlite is a popular ratio) or other fibres. The perlite keeps things airy and prevents the mix from becoming waterlogged.
Hydroponic systems
Use as a standalone hydroponic medium in run-to-waste or recirculating setups. Its free-draining nature means roots stay well oxygenated — crucial for preventing root suffocation in hydroponic environments.
Propagation
Layer perlite beneath cutting trays to improve aeration around developing roots. Makes a real difference to strike rates.
Safety note: Wear a mask when handling dry perlite to avoid inhaling dust. It's straightforward stuff, just respect the material.
Technical specifications
- Composition: 100% expanded volcanic perlite
- Granule size: 0–6mm
- pH: 6.5–8.0 (neutral)
- EC: 0.0–0.1 mS/cm (essentially zero salts)
- Sterility: Pathogen-free, germ-free
- Certification: RHP approved
- Recommended mix ratio: 10–35% by volume (depending on application)
Who this is for
- Growers building their own substrate mixes and wanting reliable aeration without premium prices
- Hydroponic growers looking for a cost-effective alternative to rockwool or expanded clay
- Anyone running soil-heavy mixes that need better drainage and root space
- Propagators improving cutting strike rates through better aeration
- Growers who value sustainability and reusable media
Our take
Plagron Perlite does one job and does it properly: it keeps your growing medium open, aerated, and draining clean. RHP certified, consistently sterile, and priced so you're not mad about buying it in bulk.
Whether you're mixing your own substrate or building a hydroponic setup, worth picking up while clearance stock lasts. The unglamorous stuff that actually makes a difference.
