MycMonster™ XL Grow Kit
£30.00
MycMonster™ XL is a beginner-friendly, all-in-one, super simple Grow Kit built for monstrously fast growth and colossal yields.
Who’s This Kit For?
Perfect for anyone who wants grow mushrooms easily and rapidly. Whether you’re a beginner or an experienced grower, if speed and simplicity are your priorities, the MycMonster™ delivers. With full colonisation from gourmet spores in as little as 10 days due to Substrate B, it’s probably the fastest grow kit money can buy right now.
Our Advanced Sterile Substrate B
It might resemble our Cylocybe Special substrate from the MycoBox, but this is next-level. We crafted Substrate B specifically for the MycMonster™ – it’s our quickest, most advanced mushroom substrate yet, designed for rapid growth and big yields.
Inoculation
If you know how to peel a sticker, you know how to inject the MycMonster. It’s really that simple.
Easy Fruiting
You’ll be injecting and fruiting your mushrooms from the same MycMonster™ bag. An effortless, all-in-one mushroom kit.
- 2L MycMonster™ prefilled with Sterile Substrate B
- Fruiting: In same bag
- Sanitation: 2× isopropyl alcohol wipes, 1× hand wipe, 1x 18G sterile needle
- Online Instructions
Important Warnings
The specialised HEPA filters on the MycMonster™ bag manage clean air exchange – please don’t remove them.
NEVER cut open the MycMonster™ before it’s fully colonised by mycelium, or contamination may ruin the kit.
Not Included
- Gourmet spore or liquid culture syringe – you’ll need exactly 12ml (no more, no less) unless you are using a densely you have a very densely spore-filled smaller gourmet syringe.
Storage Tips
We recommend inoculating your MycMonster™ within 4 weeks of receiving it for the best results.
Helpful Advice
- Keep incubation temperatures between 20°C and 26°C
- Incubation temperatures between of 26°C provde fastest colonisation results, but do not exceed this!
- Never place this kit on direct heat, like a heatmat.
Shipping & Legal Notes
We ship from the UK to almost anywhere in the world. Each kit is made fresh to order and typically dispatched within our 3 working day aim (see our shipping and dispatch page for more info).
This product is for cultivating legal mushroom species only
Grow Guide for MycMonster™ Mushroom Grow Kit
November 2025 Update: The grow kit has recently transitioned from a multi-option format, featuring Core, Enhanced, and Deluxe choices, to the more streamlined MycMonster™ Mushroom Grow Kit.
Note: Many of the MycMonster images still show the tall, narrow bag and so need to be updated when we have a spare minute. You are just going to have to use your imagination for now, sorry! The newly upgraded MycMonster XL now comes as a much larger XL bag with a Peel 'n Inject sticker. Below is a picture of the MycMonster XL you will receive (ignore the mycelium in the photo, we injected ours with Cyclocybe Aegerita).
Follow this comprehensive guide to achieve the best results with your MycMonster™ Grow Kit.
MycMonster™ (Previously MycMonster™ Core)
- 2000ml Sterile Substrate B MycMonster with Peel & Inject
- Hygiene Kit with 2x chlorhexidine wipes, 2x hand wipes, 1x facemask and 2x sterile needles
Upgraded: This has been upgraded from a tall and narrow substrate bag to a much larger square XL bag to provide tons more room for your mushrooms to fruit.
Required: 12ml gourmet spore syringe
MycMonster™ Enhanced (Deprecated)
- 2000ml Sterile Substrate B MycMonster with Peel & Inject
- XL Fruiting Tent as an alternative for fruiting your mushrooms
- Hygiene Kit with 2x chlorhexidine wipes, 2x hand wipes, 1x facemask and 2x sterile needles
- Vermiculte for a pseudo-casing layer
- Grain SporeKit™ for optional spore testing and G2G syringe generation
Required: 12ml gourmet spore syringe
MycMonster™ Deluxe (Deprecated)
- 2000ml Sterile Substrate B MycMonster with Peel & Inject
- XXL Fruiting Tent as an alternative for fruiting your mushrooms
- Hygiene Kit with 2x chlorhexidine wipes, 2x hand wipes, 1x facemask and 2x sterile needles
- Sterilised peat moss based casing mix
- Agar SporeKit™ for optional spore testing and culture syringe generation
- Grain SporeKit™ for optional spore testing and G2G syringe generation
Required: 12ml gourmet spore syringe
1. Inoculation of MycMonster
Reducing the risk of contamination is crucial in successful mushroom cultivation, and you can achieve this by working in a small, clean, and draft-free space, ideally using a Still-Air Box (SAB) and taking thoughtful steps to reduce the chance of cross contamination.
Note: The picture below shows the original placement of the Peel n' Inject sticker on a tall, narrow MycMonster bag. However, the recently upgraded MycMonster bag is bigger than the photo and with the sticker at the top!
Before starting, cleanliness is key. Shower, clean clothes. Your hygiene kit contains a face mask and wipes for cleaning your hands and forearms also.
Next, prepare your syringe by attaching a sterile needle. Follow the inoculation instructions on your MycMonster — generally this means breaking up the substrate so it falls under the Peel n’ Inject sticker (this helps prevent piercing both sides of the bag). Peel the sticker back about 3/4 of the way, inject into the center with a 12ml gourmet spore syringe (or a smaller syringe, as long as it's dense with spores), then press the sticker back down. If you notice any creases under the sticker, peel it back and reapply.
Why isn’t the Peel n’ Inject sticker placed over the substrate? Good question. We place it away from the substrate to avoid blocking your view of the growing mycelium and to reduce risk if the sticker doesn’t re-adhere perfectly after injection (for example, if the plastic creases). If you’d rather have the injection point directly on the bag, an extra sticker is included in the hygiene kit — simply wipe the area with the green Clinell wipe, inject, and use the spare sticker to cover the hole.
Note: The picture below shows the original placement of the Peel n' Inject sticker on a tall, narrow MycMonster bag. However, the recently upgraded MycMonster bag is bigger than the photo and with the sticker at the top!
Important: Never touch or try to sanitise underneath of the peel and seal sticker, it's already sterile so you'll actually be dirtying it. Only sanitise this if you make a booboo by touching it or something! Peel, inoculate and seal - it can't get any more simple.
Inoculation Tips:
- Keep MycMonster in its packaging until you're ready to use it to minimise contamination.
- Be careful and deliberate when peeling, injecting, and sealing — move swiftly but don't rush.
- After inoculation, ensure the sticker is firmly adhered to prevent contaminants from entering.
2. Colonisation of MycMonster™
After inoculating your MycMonster, it's time for colonisation.
Colonisation Temperatures
Temperature is vital for healthy and fast mycelium growth. Use this table to find the ideal temperature for your inoculation method.
| Method | Ideal Temp | Expected Time |
|---|---|---|
| Spore Syringe | 24-26°C (75-79°F) | 10-14 Days (Sometimes takes longer) |
| AC / LC / G2G | 24-26°C (75-79°F) | 7-10 Days |
Universal Rules:
- Consistency is key. Avoid large temperature swings.
- Use an incubator or a warm cupboard. Don't ever use a heatmat with a mushroom grow kit!
- Patience is your best tool. These timelines are estimates and can vary.
For faster mycelium growth with Substrate B: when colonising at 26°C, on day 7 after inoculation thoroughly mix the substrate in the bag. Use both hands to rub the bag, breaking the contents and mycelium into a fine, loose crumble. The finer and more evenly mixed the crumble (achieved by repeatedly flipping the bag), the more uniform the mycelial distribution and the faster the colonisation. Do not repeat the step more times than this — repeating it can stall growth. Leave the bag to continue colonising afterwards.
Important: Using a heat mat is like trying to hatch an egg on a frying pan. It creates an environment that’s too hot and uneven, drying out the base of the grow kit while sending moisture upwards. This leads to soggy conditions and bacterial growth. For optimal results, create a stable, warm environment instead. Build or buy an incubator or put a radiator inside a small cupboard or just incubate at room temperature (slower colonisation is better than growing a bag of microbes).
3. Post Colonisation Stage
When your MycMonster is done colonising, it's now time to move on to fruiting some mushrooms! As the MycMonster is designed to be fruited within the same bag* (which was recently upgraded to a be a spacious XL bag), we first need to hydrate the 'cake' of white mycelium.
3.1. Dunking for Humidity and Hydration
When the substrate inside the MycMonster bag has fully colonised (completely covered in white mycelium), you should use a method known in the hobby as 'dunking' to get as much water into the mycelium cake as possible.
There are so many different ways to acheive this hydration, but the easiest is to simply add water to the MycMonster bag. We'd suggest a couple of litres of spring water (but tap can work too). Pour this over the myc cake, then weigh the cake down with a clean plate or three (as it will try to float!).
Fold over the top of the bag to keep everything as clean as possible. Leave your cake submerged like this for anything between 12-24 hours, depending on how much patience you have!
Dunking Troubleshooting Tips:
- Ensure the cake is 100% colonised before dunking.
- Make sure the cake remains fully submerged for the entire dunking period.
- Fold the top of the bag while dunking.
- Longer dunking periods (closer to 24 hours) generally produce better results.
After this dunking period, drain the water from the MycMonster bag and give it all a good rinse with clean tap water (spring is fine too, but it's not necessary) and then drain thoroughly as we don't want stagnant water pooling.
3.2. Enhanced / Deluxe? This Part's For You:
Preparing Your Grow Tent
Grab the bag of perlite which was included with your kit. This volcanic rock has an insane super porous surface which is perfect for storing heaps of water inside which then easily evaporates off, producing high levels of humidity in the process.
But when it's dry, it's horribly dusty so we'll show you how to prepare it without stirring up a ton of fine white dust into your homes...
To prepare the perlite, open a corner of the zip seal bag, run tap water into this until the perlite is completely drenched, zip it shut and leave it for 30 mins to maximise its water uptake. Afterwards, drain the excess water by cutting a small corner off the bag and allowing the water to stream / drip out. Once it's finished (or when there's barely any dripping happening), the perlite is ready for the next steps below.
4. Different Fruiting Options/h2>
Choosing the right fruiting method varies a little based on the kit you've purchased or if you have your own fruiting chamber. This section outlines the ideal conditions and specific techniques for each type of kit, enabling healthy mushroom development during the fruiting stage. Note: For all methods, aim for temperatures between 18-24°C (65-75°F), with 21°C (70°F) as a solid middle ground for many popular species.
Now let's outline the differences and steps for each kit:
MycMonster XL (Previously Known as 'Core')
As your MycMonster XL is an all-in-one, the main objective from this point onwards is keeping the temps warm and waiting for it to start pinning.
MycMonster (Enhanced & Deluxe)
Here are the steps needed to get the perlite and cake into the bag. Notice we are creating a little barrier between the cake and the perlite, so the cake isn't directly touching the perlite.
Steps:
1. Pour your soaked perlite into the included XL tent
Option A
2. Rip a strip of tin foil and place this on top of the perlite.
3. Remove the mycelium cake from its bag and place this on top of the foil which now rests on the perlite
Option B
2. Forget the foil and just cut all around the MycMonster bag (just above the top of the mycelium cake).
3. Sit this plastic covered cake on top of the perlite.
4. Make sure your casing layer is nice and damp (vermiculite for Enhanced / sterile peat moss-based for Deluxe) and spread this evenly over the top of your cake.
5. The Best Bit... Fruiting Your Mushrooms!
Maintaining a temperature of around 21°C (give or take a couple of degrees) during the fruiting stage is ideal for best results with many popular species of mushrooms. Essential levels of humidity will naturally build up inside the grow tent or bag from the water you allowed to soak into the substrate during dunking.
Unlike some other grow kits, you don't need to mist your MycMonster (unless it looks dry). Misting can help promote faster pinning, but once you see them - feel free to leave it all alone from that point. The only time you ever really need to open your grow bag after the onset of pins is when you're ready to harvest your fully grown mushrooms. Even peeking for a few seconds is enough to lose some humidity if you aren't careful, which can sometimes cause growth defects.
Humidity and Air Exchange
Humidity and FAE (fresh air exchange) are extremely important for pinning and healthy mushroom development, as is temperature and light. They all need to work in harmony.
We suggest cutting a 1cm slit through both sides of the tent near the top and placing an electric fan somewhere in the room on a low setting (but don't go out buying one if you don't already have one). Even opening a window from time to time can be great for creating some air currents which will help increase the FAE inside the grow tent.
Light and Environmental Conditions
Your mushrooms will need light to grow. We recommend indirect sunlight or a 5000-6500K LED or fluorescent light a few feet away - if the light is heating the substrate, move it further away.
If you notice the inside of your bag looking dry, it may be due to the fan being too close, the holes you cut being too big, or grow lights (if using them) being too close and hot. Observe what's happening and adjust your setup as required. Fantastic results depend on it.
Pinning and Growth
After around 3-7 days, you'll hopefully begin to see lots of tiny white dots. These are hyphal knots that will develop into primordia, aka mushroom pins. It will take 4-5 days for them to grow into fully mature mushrooms ready for harvest.
During this time, they'll let you know if something isn't quite right. Fuzzy mycelium at the base of the mushrooms and/or thin stems are an indication that more FAE is needed. Increasing the fan speed or length of the cuts on the tent or bag might be something to try.
Don't worry about any mushrooms growing around the sides and bottom of the cake. You'll still be able to harvest them. If you want to give your mushrooms more room to grow next time, consider using a fruiting chamber instead of the bag.
Fruiting Troubleshooting Tips:
- Water pooling: If you see pools of water touching the substrate, dab them with a paper towel. Standing water can become contaminated quickly.
- Temperature issues: Maintain stable temperature between 18-24°C. Unstable temps can lead to excessive condensation.
- Fuzzy stems: This indicates insufficient fresh air exchange (FAE). Try increasing airflow slightly.
- Dry substrate: Only mist if the substrate looks dry; otherwise, humidity should come from the substrate itself.
- Aborted pins: Often caused by environmental changes. Maintain consistent conditions.
Harvesting and Subsequent Flushes
When the veil beneath one of your mushroom caps is about to tear off, this is when you should harvest your first flush. For best results, you should repeat the dunking process after each harvest. If you've taken good care of your grow kit, you should achieve multiple flushes of beautiful mushrooms before the nutrients are all used up.
Expected Yields
With proper care and optimal conditions, the MycMonster™ can produce impressive harvests across multiple flushes. Remember that each flush typically produces less than the previous one, with the first flush usually being the most abundant.
Happy shroomin' folks!
Last updated on 10 November 2025




