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How to Make a Monotub: The Complete Monotub Tek Guide

The monotub tek method is where most indoor mushroom cultivators get their start. It's easy, fast, and doesn't take up much space or require high-tech humidity or ventilation systems.

The monotub method is most often associated with the cultivation of manure loving P. Cubensis Like Golden Teacherbut can also be used to grow edible species of manure-loving Agarcarius (like White Button or Cremini) or (Coprinus comatus).

Want to switch things up? Swap out that plain jane substrate and get our premium substrate that has hardwood in it so you can also grow mushrooms like oyster shitaki or rishi. The potential for innovating and creating new mushroom growing techniques utilizing monotubs are limitless.

What do I need to make a monotub.

  • liquid culture syringe

  • Spawn bags or fully colonized grains

  • Clear plastic bin (like those made by Sterilite) or a pre made mono tub

  • Thin opaque black trash bags (if you are going to make your own monotub)

  • stick back filter disc or 2 inch clear water proof medical tape

  • drill with a 1.5 inch drill bit

  • 70% rubbing alcohol

  • Two spray bottles (one for alcohol and one for water)

  • Bulk substrate like our premium substrate (which is universal)

  • Still air box to inoculate in a clean environment

Step 1: Make or buy mushroom grain spawn

First off, you'll need to get your mushroom grain spawn colonizing so it can be used in your monotub. Grain spawn is sterilized grain that has been fully colonized with mushroom mycelium. It's the equivalent of seeds for mushroom growers.

If you plan to grow a dung-loving mushroom species that isn't commonly available, you will need to make your own.* To do that, you will need sterile grain bags (also called spawn bags, mushroom grow bags, or grain substrate) are filled with a blend of sterilized grains. Ours features a blend of hydrated popcorn, red winter wheat and rye berries. The bags feature a self-healing injection port meant to work in tandem with a spore or culture syringe.

Be aware that although hallucinogenic mushroom spores are legal in most jurisdictions in the United States for microscopy use (studying them under a microscope) the millisecond they form hyphae and become mushroom spawn or mycelium or are used with intent to cultivate mushrooms they become illegal. Hallucinogenic mushroom spores themselves are illegal in a number of U.S states including the state of California. Be aware of the legality in your place or residence!

To inoculate your injection port grain bag, simply inject 2.5ml of spore syringe or liquid culture through the port in a sterile (or at the very least impeccably clean) location. Make sure to sterilize your hands, the syringe needle, injection port bag, and inoculation surface with rubbing alcohol. And always wear nitrile or latex gloves. Additionally, make sure to inspect the bag for any micro tears or contamination. Any tear in the bag will compromise its sterility.

If you've ordered a sterilized grain bag online, it is best practice to wait at least one week before injecting it to make sure that it wasn't damaged in transit. If it shows any signs of contamination (usually green mold) discard the bag. (If it's from TMU , just reach out to us for a replacement!) Allow your bag to colonize in a cool location out of direct sunlight. The temperature for incubation shouldn't exceed 75 degrees F or dip below 55 degrees. After a couple weeks or so you should start to see mycelium growing on the grain. You'll notice the white mycelium growing outward from the injection point. When it has grown three to four inches you should, without opening the bag, carefully break up the colonized grain and mix it into the uncolonized grain. This will dramatically speed up the colonization process. When the bag is completely white with mycelium your spawn is ready to use. This may take a couple weeks to a month or more depending on the species and vigor of your culture.

Step 2: Make or buy sterile bulk substrate

Your bulk substrate formulation will depend greatly on what species of mushroom you are growing in your tubs. If you are growing edible wood loving species you'll need to track down wood chips that are made up of mostly hardwood species such as oak or maple wood. If you are growing manure-loving species continue reading!

We recommend our premium substrate It's easy to use, already cooked and sterilized, and is a formulation perfected over many years of Agaricus trials. It will save you the hassle of tracking down your own ingredients and cooking horse poo at home...

If you decide to make your own manure substrate blend, the easiest formulation is 50% coco coir and 50% horse manure. Coco coir can be purchased by the bag from most grow shops specializing in hydroponic or urban gardening. The best horse manure will have to be sourced from farms that board horses, offer riding lessons, etc. Best is manure that has been composted for at least 6 months.

At this point you can either pasteurize your bulk substrate by cooking it in an oven or steaming it. You'll need to mix the two ingredients together and hydrate the mixture to 'field capacity.' If you grab a handful of the substrate and squeeze it as hard as you can you should be able to get one or two drops of water to drip out. More than that and the mixture is over-hydrated: add more coco coir. If it is under hydrated add water little by little and continue to test it.

For the oven method just preheat it to 170 degrees and cook the bulk substrate on baking pans with a tinfoil cover for at least 2.5 hours.


To use the steam method, bag the substrate in large grow bags and cook it in a pressure cooker or steam it until it reaches around 160-180 degrees F.

Allow your bulk substrate to cool completely before using it!

Step 3: Make your monotub

There are many ways and materials you can use to make a monotub. Most frequently large Tupperware style containers are used such as those made by Sterilite. If you choose to use this type of clear plastic container, we recommend using an opaque plastic bag as a liner for the bottom of your monotub to help prevent mushrooms from growing on the sides or bottom. The mushrooms that grow this way are nearly impossible to harvest yet will use up valuable nutrients and energy from from your substrate. Best to keep them from growing in the first place and allow the mycelium to put all its energy into creating mushrooms in easily harvestable parts of the bin.


  1. Purchase the bin of your choice. Make sure that you get a lid with it!

  2. Use a hand drill outfitted with a 1.5 inch drill bit or hole saw (a modified drill bit for making larger holes). Drill holes around the outside of the monotub, running the drill in reverse can prevent the plastic from cracking. One hole every eight inches of length should be adequate with at least one hole on each end of the monotub. You want your holes to be just above the bulk substrate that you'll be filling the monotub with, just above your liner or part of the tub that is painted.

  3. Cover the holes with 2 inch medical tape or sticky back filter patches. This will allow the substrate to breathe while limiting any particulates in the air from entering your tub.

  4. If you're using a contractor bag liner, fold the bag so that the bag fits snugly into your monotub and the top of the liner is about halfway up the side of your monotub. This is where you'll put your bulk substrate.

  5. Et voila! You have your monotub ready to grow mushrooms.

Step 3.5 (optional): Set up your FAE fan and humidifier

If you are choosing to upgrade your monotub with a FAE fan and humidifier, you can easily install them however you feel works best for you.

Step 4: Sanitize your work space and monotub

This is a very very important step! You want to make sure you give your mushroom culture every advantage possible. Put some rubbing alcohol into a spray bottle and sterilize your entire tub. Spray your hands, your working surface, any scissors you might use to cut your spawn bag open etc.

Spray the outside of your spawn bag and your bulk substrate bags and rub the alcohol around the entire bag.

Make sure the room that you are inoculating in is clean! If you have pets make sure the room has been recently vacuumed (although not so recently vacuumed that there may be air turbulence or particulate matter floating around). Better yet, if you have access to a still air box for mycology work, this would be a great time to use it!

Close windows. Close doors. Be paranoid about contamination.

Be sure to sanitize your monotub.

Step 5: Load bulk substrate into monotub and inoculate it

Inoculating your bags or jars.

Now for the fun part! The amount of bulk substrate and spawn you use will be dependent on the size of your monotub. You want to have 3-5 inches of substrate. Four 2lb grain bags should readily fill one moderate sized tub. Again, this is a great time to make use of your still air box.

You want to start by sprinkling about one inch of bulk substrate into your sterilized monotub, or in the liner if you're using one. Make sure your bulk substrate is still at field capacity (see if you can squeeze out a couple drops of water from it!) If it dried out during pasteurization you'll need to add sterilized water to the blend as your fill your tub.

Then add a thin sprinkling of colonized grain spawn. Add another inch of substrate followed by more spawn. Keep sandwiching spawn in layers of bulk substrate until you've reached your desired depth.

Make sure the lid to your monotub is also sterilized with rubbing alcohol.

For good measure use a paper towel with more rubbing alcohol and wipe down the sides of the monotub just above the inoculated bulk substrate.

Put the lid on your monotub and don't remove it again until the monotub is fully colonized!

Keep the monotub someplace warm, but not hot, and out of direct sunlight but with some ambient light present.

Step 5.5 (otional): Dial in your FAE fan and humidifier

If you're choosing to upgrade your monotub with a FAE fan and humidifier, now would be the time to to dial in your settings. These will be entirely dependent on the species you are growing and your own environmental conditions, so it may take some trial and error balancing FAE with the humidity controls. Relative humidity of between 80 and 90% is recommended for most species as mushrooms will dry out or not fruit at all if humidity levels are too low.

Step 6: Watch the monotub for signs that it's fully colonized

Check on your bin daily to watch it colonize. You'll see white spots start to expand from each point of grain spawn. Over time they will completely cover the surface of the bulk substrate. You should see small droplets of mushroom exudate. This is natural and a sign of proper hydration and a speedy colonization.

You want to look for the signs of pinning mushrooms. This usually looks like white hyphae growing pinning vertically from the surface of the substrate and forming little knots of dense white mycelium.

Tubs will take 2-3 weeks to fully colonize for most dung loving species. Wood loving species colonization rates will vary.

Step 7: Case the substrate and wait for fruiting

When you start to see hyphae knots or pins you'll want to case your monotub. You can now safely remove the lid from your bin.

Add a thin 1/4 layer of casing (you can buy it from us or make it yourself)to the bin and spray the bin with water until the casing is showing signs of being fully hydrated.

Spray the tub daily with water and keep the lid of the bin slightly offset to allow a bit more oxygen flow to the tub. Make sure the bin gets some light to allow the mushrooms to grow in the correct direction. Although mushrooms don't photosynthesize like plants do, light still helps them grow healthy and in the correct direction!

Harvest your mushrooms at the stage you desire. For most species this is before the caps have flattened out.  

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Hey thanks for adding me I'll be looking forward to learning how to cultivate some bomb shrooms thank you

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I can't tell what happened? Looks like everything was working ,and SOcloseTogetheer?


Jay  Hurst
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Jan 07

Just getting ready to start my journey- starting with a isolated/clone golden teacher (big) I’m using grain bag with double tub incubator with fish aquarium heater in bottom tub. What’s the best temp to incube grain bag at ??

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The group forum is where it's at. I did a bunch of grows last summer with barely any knowledge. Mainly I got lucky. I've learned a lot over the cold months. Lots of trial and error. But the Army has had my back through it all. All the ups and downs. They've been there to cheer me on and teach me along the way. Growing mushrooms is more than a passion I've learned, it's a lifestyle. I hope to see you there.


Thank you for your hard work and dedication. You are helping me to change my life. And I am doing myself, No more SCAMERS!

James Leach
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If you’re still looking for answers our Group Chat is filled with people just like you.

We work with you, help you find TEKS that work for you by people who make the same Teks work for them.

We can get you on a path to the Better You you’re looking for

Either Way, Good Luck on your Journey.


The TMU Army


Dec 17, 2023

Thank you!

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