Home / Mushroom Cultivation / Mushroom Grow Kits / MycMonster
Mushroom grow kit
MycMonster
Our big, fast all-in-one bag. You inject a single 2L bag of Substrate B with your own gourmet culture and fruit in the same bag. Full colonisation in as little as 10 days.
Out of stock
Want to know the moment it returns?
For cultivating legal gourmet mushroom species only. A gourmet liquid culture or spore syringe is not included.
filled and sterilised fresh to order
arrives sterile or we replace it
any gourmet species, your choice
full colonisation in as little as 10 days
The short version
A single-stage all-in-one gourmet mushroom kit. You inject your own culture straight through the sterile 2L bag and both colonise and fruit in that same bag. It is built around Substrate B, our fastest substrate, so it can colonise fully in as little as 10 days and then throw large flushes. The culture is not included.
How it works
How a MycMonster grow works
The MycMonster is a single-bag kit. There is no separate spawn jar and no tray to mix, so the whole grow happens inside the 2L bag from the day you inject it to the day you pick. Four stages, clean hands, a warm spot and some patience.
Inject through the bag
The MycMonster has no rubber port. You inject straight through the sterile bag surface with the included 18G needle, wiping the spot with an isopropyl alcohol wipe first. Work somewhere clean and draught-free, and aim the needle into the substrate rather than the air gap at the top. It needs 12ml of culture, no more and no less.
Colonise the substrate
Leave the bag somewhere steady and warm and let the mycelium run through Substrate B. Aim for around 24 degrees, though anywhere from 18 to 24 is fine as long as it stays consistent. Watch for condensation and skip the heat mat. Do not open the bag, and never cut it before it is fully white throughout, or you risk losing the grow. Thanks to Substrate B this can take as little as 10 days.
Open for fresh air
Once the substrate is colonised solid white, the kit is ready to fruit in the same bag. The HEPA filters on the bag handle clean air exchange during colonisation, and opening the top introduces the fresh air that triggers pinning. Drop the temperature a touch, to around 20 to 22 degrees, and give it some indirect light.
Fruit and harvest
The humidity comes from the substrate, so you do not need to mist a colonised MycMonster unless it looks dry. Pins appear within a few days, then bulk up. Harvest each mushroom just as the veil under the cap begins to tear, then rehydrate the cake between flushes for more. First pins usually show in 3 to 7 days after you open the bag.
Why this one
What makes the MycMonster different
The MycMonster is the big, fast one. It is built around a single 2L bag of Substrate B, our quickest substrate, so there is no grain stage to colonise first and no mixing step. You inject once and the whole bag is the grow.
Substrate B might look like the Cylocybe Special substrate from the MycoBox, but it is a different recipe, developed specifically for this kit and tuned for rapid growth and large flushes.
Why it works
How we make it sterile
Sterile is the whole point. Substrate B is dense and nutritious, which is exactly what fast colonisation needs, but it also means any stray microbe would thrive in there too. So the bag has to reach you perfectly clean.
Autoclaved
The bag is filled with Substrate B and sterilised under heat and pressure in an autoclave, killing off anything living in the substrate before it ships.
Cleanroom sealed
It is handled and sealed in a HEPA-filtered cleanroom in front of a laminar flow hood, so nothing settles back onto it after sterilising.
HEPA filters
The bag carries its own HEPA filter patches that let the colonising mycelium breathe while keeping airborne contaminants out. Please do not remove them.
Worth noting
No process is ever perfect, which is exactly why every kit is backed by the Sterile Guarantee further down.
In the box
What's included
One bag, ready to inject. Everything bar the culture, which you add yourself.
The MycMonster
Needs 12ml of culture
- 2L MycMonster bag, prefilled with sterile Substrate B
- HEPA filter patches built into the bag for clean air exchange
- 1 sterile 18G needle
- 2 isopropyl alcohol wipes
- 1 hand wipe
- Online instructions
The one thing you add
What you'll need
A MycMonster arrives sterile and ready to inject, so you supply the living part: a gourmet liquid culture or spore syringe. This kit needs exactly 12ml, no more and no less, unless you are using a smaller but very densely spore-filled gourmet syringe. We make gourmet liquid cultures you can inoculate it with.
Liquid culture has known, predictable genetics and can be incubated a little warmer, so it tends to colonise faster and more reliably. Spore syringes are cheaper and offer more variety, but are never fully sterile, so incubate them slightly cooler to let the mycelium outrun any stragglers.
Whatever you inject with, give the mycelium a clean start: wipe the injection spot with the alcohol wipe and work in still, draught-free air. Most failed grows trace back to a sloppy injection rather than a bad kit. We stock the sterile gear for it (a still-air box, wipes and gloves) in sterile and lab equipment.
Risk, reversed
The Sterile Guarantee
Every MycMonster is made fresh and arrives sterile and sealed. If one shows contamination on arrival, before you have injected it, send us photos and we will replace it. What happens after you inject comes down to your technique and conditions, which no reputable seller can promise for you. So we stand fully behind the bag reaching you clean, and the troubleshooting below helps with the rest.
At a glance
The spec sheet
- Kit type
- Single-stage all-in-one bag, inject and fruit in the same bag
- Vessel
- 2L HEPA-filtered MycMonster bag
- Substrate
- Sterile Substrate B, our fastest, prefilled in the bag
- Inoculation
- Inject straight through the bag surface, no rubber port
- Culture needed
- Exactly 12ml, no more and no less, not included
- Colonisation temp
- Around 24 degrees, 18 to 24 is fine if kept steady
- Fruiting temp
- A little cooler, around 20 to 22 degrees
- Colonisation time
- As little as 10 days, thanks to Substrate B
- Use within
- Inject within about 4 weeks of receiving it for best results
- Made
- United Kingdom, fresh to order
- Suited to
- Gourmet species: oyster, Lion's Mane, Shiitake and similar
When things look off
Common issues
Because you do the growing, the odd thing can go sideways. Here are the common ones and what they usually mean.
Nothing happening
Usually patience or temperature. Even Substrate B needs a few days to take hold. Trace the mycelium edge through the bag with a marker and check again. Cold slows it right down.
Yellow liquid
Normal. That is metabolites, the mycelium's own waste, not contamination.
Green, grey or sour
That is contamination. Keep the bag sealed, bin it safely, and keep a contaminated bag away from your others.
Thin stems, no pins
Not enough fresh air once you have opened the bag. Open it up more and add a little airflow in the room.
The full step-by-step lives in the MycMonster grow guide, and the grow-kit troubleshooting guide goes deeper on contamination and temperature.
Other kits
Not sure this is the one?
Common questions
Frequently asked
Aim for about 24 degrees while it colonises; anywhere from 18 to 24 is fine as long as it is steady, and keep an eye out for condensation. Drop it a couple of degrees, to around 20 to 22, once you open the bag to fruit. Avoid heat mats, they cause condensation.
The MycMonster has no rubber port. You inject straight through the sterile bag surface with the included 18G needle, after wiping the spot with an isopropyl alcohol wipe. If you can peel a sticker, you can inject this kit, that is how simple it is.
Exactly 12ml, no more and no less, unless you are using a smaller but very densely spore-filled gourmet syringe. The culture is not included; you add your own gourmet liquid culture or spore syringe.
Any legal gourmet species you have a culture for. It suits oyster mushrooms, Lion's Mane, Shiitake and similar. We sell gourmet liquid cultures you can inoculate it with.
Substrate B can colonise fully in as little as 10 days, then it fruits in the same bag, so roughly 3 to 4 weeks from injection to the first flush, depending on species and temperature.
The HEPA filter patches let the mycelium breathe while keeping airborne contaminants out, so leave them in place. Never cut the bag open before it is fully colonised white throughout, or contamination can ruin the kit.
Send us photos before you inject it and we will replace it, that is our Sterile Guarantee. Contamination that appears after you inject comes down to technique and conditions, so check the troubleshooting first.
Liquid culture has known, predictable genetics and can be incubated a little warmer, so it colonises faster and more reliably. Spore syringes are cheaper and offer more variety, but are never fully sterile, so incubate them a little cooler.
Ask the community
Questions and answers
No questions yet. Yours could be the first.
For cultivating legal gourmet mushroom species only.Sold as a sterile substrate kit for home cultivation. We trust you to be responsible.