You have no items in your shopping cart.
Vermiculite Grade 3 | 1 L & 5 L Bags
Coarse grade 3 vermiculite — the second of the three pillars of the classic CVG substrate. Available in 1 L and 5 L bags. Holds up to four times its weight in water while keeping enough air space for mycelium to breathe. Use in CVG mixes, casing layers and PF Tek substrates.
Availability: In stock
€2.95
Related
Check items to add to the cart or select all
Product Description
Details
Vermiculite is the workhorse of mushroom cultivation. This expanded mica mineral holds water like a sponge, releases it slowly to the mycelium, and creates the air spaces that keep colonisation aerobic. Our grade 3 vermiculite is the coarse particle size that bulk-substrate recipes call for.
Product specifications
- Available sizes: 1 L and 5 L bags
- Grade: 3 (coarse, ~3–6 mm particle size)
- Composition: 100% expanded vermiculite (hydrated phyllosilicate)
- Water capacity: holds 3–4× its own weight in water
- pH: slightly alkaline (7.0–8.5)
- Properties: sterile by nature, lightweight, water-retentive, aerative
Three key uses in mushroom cultivation
- CVG bulk substrate — combine with coconut coir and gypsum at 2:2:1 by volume (the classic CVG recipe). Vermiculite contributes water retention and air gaps.
- Casing layer — a 1–2 cm layer on top of colonised substrate to trigger pinning and keep the surface moist
- PF Tek substrate — the original PF Tek recipe is 2:1:1 vermiculite : brown rice flour : water, sterilised in half-pint jars for Psilocybe cubensis cultivation
Which mushrooms grow on vermiculite-based substrates
- Psilocybe cubensis — all strains (PF Tek, CVG bulk)
- Pleurotus eryngii — king oyster (CVG bulk)
- Stropharia rugosoannulata — wine cap (CVG bulk)
- Agaricus bisporus — button mushroom (casing layer)
For wood-loving species like shiitake or lion's mane, use beech woodchips instead.
How to mix CVG with this vermiculite
- Measure — 2 parts coco coir : 2 parts vermiculite : 1 part gypsum (by volume)
- Hydrate — add water until the mix holds together when squeezed, but no water drips out (field capacity)
- Pasteurise — heat to 65–82 °C for 1–2 hours
- Cool — bring the mix down to 24–27 °C
- Inoculate — add fully colonised grain spawn at 1:2 ratio by weight
Safety note
Modern horticultural vermiculite from European mines is asbestos-free and safe to handle. Still, always wet vermiculite before use to minimise dust, and wear a dust mask when opening a fresh bag.
Skip the DIY step
If you'd rather buy CVG ready-mixed, sterilised and bagged: .
Pair with the rest of your kit
Build a complete bulk substrate with the other two CVG pillars: and . Add aeration with .
Storage
Store unopened bags in a dry place, away from direct sunlight. Vermiculite has an indefinite shelf life when kept dry.
Additional Info
Additional Info
| Productcode | zgn-vc30 |
|---|---|
| Origin | No |
| Sterile | No |
Customer Reviews
13 Item(s)
per page
- perfect Review by Stray
-
good price, good amount, fast delivery, always works (Posted on 4/14/2026)Rating - Very good Review by Ivo
-
I am very satisfied with this product! 5* (Posted on 5/8/2025)Rating - Perfect Review by Shroom Master From Finland
-
Perfect product for mushroom cultivation. (Posted on 12/14/2023)Rating - It's vermiculite Review by Kid Fantastic
-
It's vermiculite... in a bag! This vermiculite is coarser than what is typically used as a casing layer, but it works. (Posted on 12/9/2022)Rating - GOEDE KWALITEIT Review by ERWIN
-
Goede kwaliteit korrels, prijs is ook ok! (Posted on 9/17/2022)Rating - Good but small Review by Sofia
-
Nice quality vermiculite, but it's way less than I thought, 1L is a very small bag! (Posted on 2/3/2022)Rating - Very nice Review by Psilocin
-
Bought vermiculite before on ebay, but this one looks lot better - at a far lower price as well. Would definitely recommend buying vermiculite from here for any necessities ! (Posted on 1/18/2020)Rating - good Review by Petre
-
pretty good (Posted on 10/26/2019)Rating - Good quality vermiculite Review by Muad’Dib
-
Good quality vermiculite but of course you could get it much cheaper when you buy big amounts like 100 liters elsewhere. (Posted on 5/30/2019)Rating - Perfect for Cakes Review by Baciu
-
It's really coarse. (Posted on 12/20/2018)Rating - good Review by Dominique
-
good substract, good water retention, I have some mushoroom wake up inside my jar with vermiculite... that mean good retention (Posted on 10/2/2018)Rating - Nice! Review by M. M.
-
High quality vermiculite. Perfect for cultivation. (Posted on 8/10/2018)Rating - Perfect Review by Nick
-
No problems (Posted on 5/17/2018)Rating
13 Item(s)
per page
You may also be interested in the following products:
