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XL Rye Grain MykoBox Grow Kit

Step by step instructions for your XL Rye Grain MykoBox Grow Kit, from inoculation to harvest.

  • Steps: 7 steps

Updated 29th September 2026

The container

ContainerSAC O2 Microbox TP1200, from Belgium
Size1200 ml. Lid 180 x 120 mm, base 172 x 110 mm, 70 mm tall.
MaterialClear, tough polypropylene, so you can watch the mycelium grow. The lid seals airtight.
FilterWhite #30 filter in the lid: SAC O2's middle air-exchange grade, white rather than red so the colour is never confused with contamination.
How the filter worksRandomly arranged fibres, working on the HEPA principle, trap mould spores, mites and thrips while air passes through.
HeatCan be autoclaved at up to 123 °C.
AfterwardsBox and lid are 100% recyclable.

What's in your kit

  • 1200ml MykoBox of coffee-enhanced organic rye grain and gypsum (18x12x7cm), with a HEPA-filtered Inject-Thru™ lid
  • XXL Grow Tent to fruit your mushrooms inside
  • Filter material for the tent's top-FAE gap
  • 2L perlite to keep the humidity up while your mushrooms fruit
  • Hygiene Kit: face mask, 2x hand wipes, 1x 70% IPA / 2% Chlorhexidine wipe and 1x spare sterile needle, plus sterile gloves if you picked a glove size
  • Bonus: a bag of coir, in case you want to try a monotub-style grow

You will also need

  • A gourmet spore or culture syringe (2-3ml)
  • A strainer or sieve for rinsing the perlite
  • A spray bottle for misting
  • A clean scalpel or knife for harvesting

Step 1

Inoculation of your MykoBox

Work in a small, clean and draught-free room. We always recommend working within a Still-Air Box (SAB) when inoculating any product.

A clean set-up: a Still-Air Box (SAB) with the syringe and MykoBox inside, ready to inoculateOpen the photo full size
The Rye Grain MykoBox from the top, showing its injection port and the rye grainOpen the photo full size
  1. Get clean: Make sure you're showered with fresh clothes. Clean your hands and forearms with the hand wipe for 40-60 seconds and let them dry completely before fitting your gloves - trust us, you won't get them on otherwise!

  2. Get your syringe ready: Give your syringe a good shake to break up any clumps, then screw on the sterile needle we've given you.

  3. Take your MykoBox out of its bag: We bag it under clean filtered air-flow before heat-sealing it, so the injection port is clean enough to inject as long as you don't touch it. If you do touch it, give it a wipe with the 70% IPA / 2% Chlorhexidine wipe for 40-60 seconds and let it dry for a few seconds.

  4. Leave the filters alone: The white HEPA filters on the lid filter out dust and mould spores and allow clean air exchange. Don't touch them or try to remove them!

  5. Inject: Pierce the grey rubber injection port - there's just the one - and inject 2-3ml of your gourmet spore or culture solution. Now give it all a thorough shake to distribute the solution as far and wide as you can.

Step 2

Colonisation of your MykoBox

Place your MykoBox somewhere warm to fully colonise. Temperature is so important for success - 23C (give or take a couple of degrees) is common for many species. Being too hot or too cold may result in contamination or slow to no mycelium growth.

Using a liquid culture, agar or grain-to-grain instead of spores? Aim for 26C - those are live mycelium, not spores.

  1. Keep it steady: Try to maintain a consistent temperature, i.e. don't let it go up and down too much.

  2. Avoid heat mats! They will cause excessive condensation leading to water build-up and an easy pathway for contamination to enter your MykoBox. Consider building or buying an incubator if you're struggling to keep the temperature up - it's way cheaper than keeping your home heating on all the time and gives much better results too.

  3. Keep it out of direct sunlight: A cupboard or a shelf out of the sun is perfect.

  4. How long? With a culture syringe, it can be colonised in 10-14 days. With gourmet spores it's a few weeks, give or take. Exact times are impossible to say - patience, it's fast enough.

  5. Ready? Your MykoBox is fully colonised when the grain is completely covered in white mycelium.

  6. Give it a few extra days: Even once it looks fully colonised, if you have the patience, give it an extra 3-7 days - this will almost guarantee full colonisation in the places you can't see.

Mycelium colonising the rye grain in a Rye Grain MykoBoxOpen the photo full size

Step 3

Perlite for maximum humidity

Rye grain doesn't hold on to water the way a coir mix does, so it can't provide much of its own humidity. That's where the perlite comes in - soaked and sitting in the bottom of your grow tent, it keeps the air nice and humid the whole time your mushrooms are growing.

  1. Cover up: Please cover your mouth and nose when working with perlite - it's dusty and nasty to work with (take it from us).

  2. Rinse and soak: Pour your perlite into a strainer and rinse it under a tap until all the dust is gone and it's soaking wet.

  3. Fill your tent: Just dump it into the bottom of your XXL Grow Tent - don't worry if it's still dripping wet.

XXL Grow Tent with wet perlite in the bottomOpen the photo full size

Step 4

Into the grow tent

The rye grain stays in its box to fruit. Once it's colonised, rye grain can break apart into individual grains far too easily if you take it out.

  1. Lid off: Once your MykoBox is fully colonised, take the lid off and store it away for another time.

  2. In it goes: Carefully place the MykoBox into the grow tent, sitting flat on the perlite with its open side up.

  3. Close it up: Fold the top of the tent over, leaving a gap at one corner for top-FAE (Fresh Air Exchange), and tuck the piece of filter material we give you into that gap. It holds the gap open, helps keep the humidity in and keeps flies and dust out.

Step 5

The best bit... Fruiting your mushrooms!

Maintain a temperature of around 21C (give or take a couple of degrees), this tends to be great for many popular species. Humidity and FAE (fresh air exchange) are extremely important for pinning and healthy mushroom development, as is temperature and light. They will all need to work in harmony.

  1. Mist and fan: Misting 3-6 times a day and fanning is recommended for best results. Open the tent, give the grain a fine mist of water, fan in some fresh air (a wave of your hand or a piece of card is plenty) and close it straight back up.

  2. Keep the perlite drenched (recommended, but not totally necessary): Perlite can dry out quickly, so be prepared to pour some water into the grow tent every other day (around the MykoBox, not into it) and mix it around with a clean hand so the perlite becomes drenched. It's okay to have an excess of water in there. Adding a little bit of 3% hydrogen peroxide to the water can help kill microbes.

  3. Fresh air: The filtered gap at the corner of the tent is your top-FAE. Place an electric fan somewhere in the room on a low setting as well - a gentle air current in the room will increase FAE inside the tent.

  4. Light: Your mushrooms will need light to grow - we recommend indirect sunlight or a 5000-6500K LED or fluorescent light a couple of feet away.

  5. Looking dry? If the inside of the tent looks dry, the room may be too cold for humidity to build up, the fan may be too close, the corner gap may be open too wide or your grow lights may be too close and drying things out. Observe what's happening and adjust your setup as required - fantastic results depend on it.

  6. Pins! After around 3-7 days you'll begin to see lots of tiny white dots - these are hyphal knots which will develop into primordia, aka mushroom pins... the exciting part! It'll then only take 4-5 days for them to grow into fully mature mushrooms ready for harvest.

  7. Listen to them: Your mushrooms will let you know if something isn't quite right - fuzzy mycelium at the base of the mushrooms and/or thin stems mean more FAE is needed, so try turning the fan up a little or opening the corner gap a little wider.

Step 6

Harvesting and more flushes

  1. Harvest time: When the veil beneath one of your mushroom caps is about to tear, it's time to harvest your first flush. If you don't get there quick enough, spores will begin to drop from your mushroom caps and make a mess! Cut them off with a clean scalpel or knife, trying not to damage the substrate too much.

  2. No dunking for rye grain: Unlike some of our other kits, you can't dunk rye grain. Taken out of its box it would fall apart into individual grains, and it wouldn't soak up much water anyway - it's just colonised grain, not a substrate like coir, which can take in massive volumes of water for its weight. That's exactly why the perlite and misting matter so much with this kit.

  3. Refresh the perlite: After each harvest, pour your perlite into a strainer, rinse it and give it a good soak before it goes back in the tent - don't worry if it's still dripping wet.

  4. Back in the tent: Once the perlite is back in, sit your MykoBox on it and close the tent up again, with the filter back in its corner gap.

  5. Repeat: Keep misting and keep the perlite wet after every flush. Show it some love (and humidity!) and you can get 3+ harvests before the substrate is completely spent of nutrients.

Step 7

Happy shroomin' ♡

Thanks so much for ordering our grow kit. We hope you love using it and reap the rewards!

If there's anything you're still unsure about, get in touch through Messages in your account or the chat button at the bottom of any page. We're a friendly bunch!

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