Updated for 2026 with a bigger SpawnTub, custom Cylo Grow Tent, massive humidity and new substrate recipe. Ready to inject with your favourite gourmet mushroom spore or culture syringes.
Made to order - usually dispatched within 3 to 5 working days.
Sterile and ready-to-inject with a spore or culture syringe of your favourite gourmet mushroom species.
Made in the UK filled and sterilised fresh to order
Sterile guarantee arrives sterile or we replace it
You inoculate it any gourmet species, your choice
Meet the MonoBox grow kit
You can harvest plenty of fresh mushrooms to share with friends and family with our MonoBox grow kit. You'll first inoculate grain and wait for it to colonise, giving you spawn. Then you'll prepare a substrate and combine both together in your MonoBox. When the mushroom mycelium takes over this, you're ready to fruit and enjoy loads of gourmet mushrooms!
If you're used to using our all-in-one kits, you'll already be comfortable with some of the steps and this will really amp up your knowledge and experience. If you're new to mushroom growing, you can absolutely jump straight in with this kit. Don't let any of the terms you might read here put you off... colonise this, inoculate that and the likes. They're simple really and you'll soon know all the lingo. The grow guide we provide will take you carefully through each step.
Working somewhere clean and draught-free, fit a sterile needle to your gourmet culture or spore syringe and pierce through the rubber port on the SpawnTub lid to add 3ml of solution to the grain. To speed up colonisation, move the needle around when distributing the solution throughout the grains.
2
Colonise the grain
Keep the SpawnTub somewhere clean and warm. Aim for around 24 degrees, though anywhere from 18 to 24 degrees is fine. Just keep it consistent and watch out for condensation. Never use a heat mat and don't open it up until your grain is fully colonised (completely covered in healthy, white mycelium). This will take 2 to 3 weeks on average.
3
Prepare the substrate
Add water to the bag of substrate mix and pop in your microwave (full details can be found in the guide, including if you don't have a microwave). Leave to cool, then mix with your colonised grain. You'll need to carefully break up your grain as it will be a solid block when you take it out of your SpawnTub. For efficient colonisation of your mix, you need individual mycelium covered grains spread evenly throughout your substrate.
4
Colonise the substrate
When you're happy with your mix, add it to your 3.1L MonoBox. Secure the lid and again, keep it somewhere clean and warm. Colonisation takes around 10 days on average, but give it an extra few days when it looks finished, to make sure the centre is full of mycelium too.
5
Fruit your mushrooms
Put the colonised substrate, now called a cake, into your grow tent. Drop the environment temperature slightly to around 20 to 22 degrees. Follow our instructions and advice on creating the right conditions, and you'll start to see your first mushrooms forming in around 3 to 7 days. Dunk your cake in water after you harvest all the mushrooms and get ready for your next flush. The first flush is the biggest.
What we cover
The Sterile Guarantee
We guarantee the kit, not the grow.
The SpawnTub in the MonoBox Grow Kit will arrive sterile. If this shows contamination on arrival, before you have used it, get in touch with photos and we will replace it. What happens after you use them though, comes down to your own technique and conditions. We don't guarantee success and no reputable seller can promise that to you. We stand by providing you with sterile SpawnTubs, the rest is down to you (with our instructions and troubleshooting guides for support!).
At a glance
The spec sheet
Kit type
Easy two-stage, grain spawn into bulk substrate
Vessel
HEPA-filtered grow box (3.1 Litres capacity, HEPA filtered), plus a new (July 2026), bigger, badder Cylo Grow Tent to fruit in (51 x 61cm, 800 gauge)
Substrate
1KG Bag of Coir / Verm / Gypsum Substrate mix post-prep
Spawn
Sterile Rye Grain SpawnTub (New style), 1L each in size holding around 1L (no headroom)
Inoculation
Inject the SpawnTub's rubber port, then shake and leave alone
Solution needed
Clean 3ml gourmet spore or culture syringe, not included
Colonisation temp
Around 24 degrees, 18 to 24 is fine if kept steady
Humidity
2L of perlite for extreme humidity levels (July 2026)
Fruiting temp
A little cooler, around 20 to 22 degrees
Time to harvest
About 4 to 6 weeks from inoculation to the first flush
Yield
800 to 1000g, over multiple flushes
Made
United Kingdom, fresh to order
Suited to
Just about any mushroom species you can think of
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, for fruiting. Avoid heat mats, they cause condensation.
No. A clean, draught-free room and the included wipes, mask and gloves are enough for most people. A still-air box lowers the risk further if you want one, but plenty of growers do fine without.
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.
No. You need to add your own gourmet liquid culture or spore syringe. You need 3 to 4ml to inoculate the SpawnTubs.
Roughly 2 to 3 weeks for the grain to colonise, about 10 days for the substrate, then a week or so to fruit. So around 4 to 6 weeks from inoculation to the first flush, depending on species and temperature.
Liquid culture has known, predictable genetics and can be incubated warmer, so it colonises faster and more reliably. Spore syringes are cheaper and offer variety, but are never fully sterile, so incubate them a little cooler.
Send us photos before opening it and we will replace it, that is our Sterile Guarantee. Contamination that appears after you inoculate comes down to technique and conditions, so check the troubleshooting first.
With good conditions, you'll harvest around 800g to 1kg of fresh mushrooms across multiple flushes.
What customers say
Reviews
★★★★★4.9 from 350 ratings · 308 written reviews✓ All from verified purchases
★★★★★✓ VerifiedReviewed 4 Jun 2025
A great place to start if you're interested in growing your own medicinal or gourmet mushrooms. Works every time.
★★★★★✓ VerifiedOrdered 10 Apr 2023· Reviewed 17 Jun 2023
Made things easy for a first time newbie. Followed all the steps carefully - in particular making sure the temperature range was right. I found each stage took a bit longer than expected but played the long game and let things develop as they needed to. The final stage in particular seemed to take ages with no action and no sign of any actual mushrooms developing despite a vigorous web of mycelium evident. But all good things come to those who wait and, hey presto, just as I was giving up hope that anything would happen, 2 months later I have harvested my first flush - over 200g of fine mushrooms. Now hoping for a second flush..
Reply from Cylocybe
Love this review, Rupert. Most folks never get around to leaving one after seeing results, so it's VERY appreciated that you put the effort into writing this. Regarding duration it takes - it changes wildly on numerous factors, especially for gourmet mushroom spores because there's a TONNE of genetics with different traits - a lottery. That's when things get really fun though... strain isolation and cloning for characteristics you want like speed, look, size, etc.
1
★★★★★✓ VerifiedOrdered 16 Jun 2022· Reviewed 7 Jul 2022
thanks Cylocybe, good instructions with this kit
1
★★★★★✓ VerifiedReviewed 1 Sep 2025
Great piece of kit, highly recommended
1
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Ask the community
Questions and answers
Q
I'm currently on fruiting stage and don't have indoor grow light, will the amount of light at this time of year slow down the process. Also do you need to maintain the temps at all times, I'm currently moving from within a room during the day for the light, to a cupboard at night to maintain the temp. I'm currently considering buying a grow light but when I've been looking I'm not sure if I'll be buying a one that's insufficient for the process (this is a one I've seen, https://www.ebay.co.uk/itm/8000W-144LED-Grow-Lights-Full-Spectrum-Lamp-for-Indoor-Home-Garden-Veg-Plant-UK-/144122681671?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=710-127635-2958-0) Any help or advice would be great. Thanks
Anonymous ··
Waiting for an answer.
Q
Hi .. I got a xxl mono box with two 3ml spores of different strains. Should I have got two of the same strains?
Anonymous ··
A
As long as you’re talking about legal to grow mushroom spores and not strains of our microscopy spores then I’ll answer this question. XL MonoBox is 1 grow kit, XXL MonoBox is also 1 grow kit. If you want to grow multiple species or strains, you’ll need multiple grow kits because you can’t grow two types of mushroom from the one grow kit.
Nick Store team
Q
When it says 500g-1Kg of fresh mushrooms is that for the xl kit or xxl kit? Also is this for a first flush or in total?
Anonymous ··
Waiting for an answer.
Q
Can the tubs be reused?
Anonymous ··
A
Absolutely :) We will have re-fills available soon too for the Coir.
Nick Store team
Q
hi there. I'm a bit over time 17 days at spawning stage 25C but the white mycelium is not fully colonised I would say 75% and there is some green colour(contamination?) on top which I have removed. I have raised the temp slightly. should I keep going or remove to bag or start again? many thanks
Anonymous ··
A
Hi Thomas, something doesn't sound right. It should take around 7-10 days to colonise - not 17. It's almost definitely a temperature related issue as the mycelium is growing too slow (too cold or fluctuating non-stable temps are the biggest cause of that, by a country mile). Can you drop us an email through the contact form and we'll have a look at your setup? :)
Nick Store team
Q
I have an XL. Instructions which I followed say 1.5-2ml injected into SpawnTub, use SAB, keep at 26 degrees and full colonisation will take around 2-3 weeks. I am on day 15 going on 16 and have no sign of growth. Can you please advise?
Anonymous ··
Waiting for an answer.
Q
Currently just started my third flush with this kit and it seems to be going well so far, considering I don’t really know what I’m doing! I was wondering though, I seem to be getting loads and loads of little tiny mushrooms and then a few bigger ones. Is there a way to get them bigger? Also when I harvest do I have to harvest all the mushrooms at the same time or can I harvest just the big ones and let the small ones keep growing?
Anonymous ··
A
Hi there, sometimes this happens with the first flush and sometimes it’s just genetics. As long as you are following the guide, you are doing everything you can do. When cropping, do them all at once. And follow the instructions for the second flush - I have my fingers crossed for you getting an insane harvest of all big mushrooms :)
Nick Store team
Q
Do you need to keep them at a set temperature when growing in the tent ?
Anonymous ··
A
This information is also in the guide, but yes - fruiting temperature for mushrooms is important. If it’s too cold then you are going to struggle growing mushrooms at home. A consistent temp of 20-24c is a typical for many popular species. If you are struggling to meet those temps, take a look at our equipment section - especially the CyLab which is a heated fruiting chamber amongst other things.
Nick Store team
Q
In the description it says you need 3ml of spore solution for the XXL kit, however the instructions which come with the kit say 3-4ml for each tub (6-8ml in total). Which is correct?
Anonymous ··
A
We temporarily advised 1.5ml, but noticed some customers experiencing slower growth so went back to recommending 3ml.
Nick Store team
Q
Can you please upload the instruction manual for the Monobox XL?
Anonymous ··
A
If you haven’t received the instructions with your order, please get in touch via the contact form :) When we have some free time, we’ll implement a digital download function on the site though.
Nick Store team
For cultivating legal gourmet mushroom species only.Sold as a sterile substrate kit for home cultivation. We trust you to be responsible.
