Grow Mushrooms At Home, Easy!

Now, more than ever, is a prime time to get a jump start on honing in your experience with growing gourmet & medicinal mushrooms at home! Maybe you have a spare room, basement space or even a shed or garage youโ€™d like to use to grow some extra food to be more self reliant, or maybe you want access to quality home grown proteins that taste great! Whatever it is, itโ€™s a golden age for learning how to grow mushrooms at home, and itโ€™s even easier now than ever! With home mushroom growers all over the world constantly innovating and bringing new ideas to the table, weโ€™ve seen just about everything there is for growing all types of gourmet, medicinal and other mushrooms like psychedelics & even ornamental mushrooms.

One of our 7lb Lions Mane kits (guest appearance of a mini-kit) in early trials of the PolyTub

Mushrooms grown from our 7lb Lions Mane kits by our friend George in a PolyTub

Some history on the SGFC & MonoTubs follows. If you prefer to skip straight to the PolyTub write up and references, click here.

SGFC? What? ๐Ÿค”

Image courtesy of my friends Tony & Tiegan @ FreshCap Mushrooms and their article โ€˜How to Build a SGFCโ€˜

Olโ€™ Trusty Shotgun Fruiting Chamber

You may have heard of a Shotgun Fruiting Chamber (SGFC), but what exactly is this?

The imagery may be confusing without visual previous visual reference, but it doesnโ€™t take a far stretch of the imagination to see why this tub received such a loving moniker.

How Does a SGFC Work?

The SGFC works with a 4โ€ณ layer of hydrated perlite sitting in a (usually) clear plastic storage bin with an array (grid) of 1/4-1/8โ€ณ holes spaced (on average) 2-4โ€ณ apart on all sides, top and bottom. The SGFC is elevated, and as best I understand it, the heavier CO2 gas pushing out through the lower level holes creates a uniform convection with a conesequence of releasing moisture into the air. Allowing the air to remain fresh & humid and growing mushrooms at home, easily & with minimal maintenance.

Who Uses The SGFC?

Popular with growers of magic mushrooms, the SGFC is best suited for cake & tray style grows. Bag style grows are possible with a large enough tub (or small enough bag) though per the commonly used design standards offers mixed results with CO2 sensitive gourmet & medicinal mushrooms which tend to have a (mostly less desirable) morphological response to CO2 dense fruiting environments.

In other words, most common gourmet mushrooms that are grown in SGFC as designed, still tend to grow stringy, straggly and while still an effective tool for growing some mushrooms, itโ€™s a lot of work to make and not always ideal for growing bagged gourmet mushrooms.

Not to say or suggest that psychedelic mushrooms donโ€™t also respond to high levels of CO2, as they do tend to stretch when access to fresh air is restricted, but they do not have the same oxygen requirements as nor do they suffer the same consequence of being unsellable as fresh product in the way gourmet mushrooms would be. Perhaps being less desirable to chefs or farmers market customers or shoppers at the store. Not all markets are the same, and some buyers are just happy with fresh mushrooms, but itโ€™s always best to try to hone in your fruiting environment and tailor it specifically to what youโ€™re growing.

Keep on reading to learn about the monotub and finally see the PolyTub in action!

What Is A MonoTub?

Image courtesy of Shroomology!

Keep Away From My Tubs!

While there is debate about who created the first monotub โ€“ monotubs quickly became a set it and forget it method of growing psychedelic mushrooms.

Most wood loving (lignophilic) species of gourmet & medicinal mushrooms prefer to fruit from a small exposed portion of the substrate. Imagine mushrooms found fruiting from damaged areas of bark on a decaying tree. In artificial mushroom logs (sawdust mushroom grow bags) we replicate this by poking holes in a colonized mushroom bag when growing Lionโ€™s Mane, Oysters (except kings) or (sometimes) Maitake to introduce fresh air (Oxygen) and allow for the fruitbodies to form. Monotubs alone are generally undesirable for most medicinal & gourmet mushroom growing purposes aside from Reishi & Agaricus sp.

Overview of Monotubs

Monotubs are generally 56-66QT plastic tubs, again using the principals of heavier gas respired by our mushrooms as they grow (CO2) vs lighter gas they use to grow (O2) to create a soft but ever present exchange of gases from inside the vessel to out, they have gained popularity due to the simplicity of their design & of course the set & forget (for the first harvest) mentality for most growers.

1/2-1โ€ณ holes are placed at (or slightly above) the intended substrate level of the tub on the long sides, and on the short sides, at the top holes are also placed. Most commonly seen is a 2 & 2 variation. These holes are initially taped (or covered with adhesive filter discs) during the colonization phase (sometimes the tub is simply covered with a bag) & once ready to fruit, the tape is removed & polyfill (pillow stuffing) is gently stuffed into the holes to allow gas exchange. Some growers prefer micropore tape, others use tyvek.

Monotubs are fairly straight forward and can be used to grow bagged gourmet mushrooms simply by spraying the tub with a mister as needed, but no one wants to do that and everyone hates forgetting or getting lazy and waking up to dry or stunted mushrooms. We can borrow the design of a monotub and combine it a portion of the SGFC to make a PolyTub that can run autonomously, and youโ€™ll see that next!


Some companies will try to sell you a fruiting chamber with HEPA filters, air pumps and all this nonsense.

No HEPA filtration is needed at the point of 100% colonization of substrates for growing mushrooms, anyone selling you this is taking advantage of you. Using enough high quality and HEALTHY mushroom spawn to colonize your substrate quickly and get your crop cycles concluded BEFORE contamination sets in is the key to a successful mushroom grow. Every substrate contaminates eventually. Save HEPA filtration (and your money) for mushroom cultures & spawn making!

Introducing the PolyTub! A SGFC & MonoTub Hybrid

Image courtesy of my friend George!

Again, thanks to my friend George! And no you donโ€™t need to keep the pillowcase inside ๐Ÿ˜‚

Monotub Collecting Dust?

For magic mushroom growers who have experience with tubs and are interested in growing gourmet/medicinal mushrooms, this is a great way to take something you probably already have laying around and put it to work.

PolyTubs are useful for bagged gourmet grows, trays or any container which can fit inside of them. I recommend at least a 56 quart, and have used up to a 110 quart without any obvious issues.

Can I Grow Multiple Species In One Tub?

You can grow multiple gourmet species in a PolyTub, but Iโ€™d stick to Blue/Grey, Gold or Pink Oysters, Lions Mane, Reishi & Piopinno. You can mess around once you get some experience growing and grow other mushrooms like Maitake or King Oysters but they will require some adjustments to get them perfect.

Combining principals of each design, while overcoming the downfalls of each, I (probably am not the first one to do this but I havenโ€™t seen it anywhere) put this together.

This came about after my best half was struggling with the morphology & humidity levels in her Lionโ€™s Mane Kit in a 66 quart, unmodified tub with an unusual strategy of stacking the kits on top of each other and flipping the tub onto the short side. ๐Ÿค”

This is the Mrs. attempt at an unmodified tub grow, manually misting and fanning. You can see the stunted fruit bodies are both dry and small, this was about 10 days in and they should be MUCH larger!

After seeing her results, I found myself realizing that growers needed a consistent way to grow my products which ruled out other environmental variablesย  without breaking the bank. Itโ€™s really simple, and is essentially a monotub filled with perlite. Putting one together is easy, if you have an old monotub already you just need to buy some perlite and youโ€™re good to go!

PolyTubs are kid approved! And yes I can print you any of my shirts in child sizes, just email us!

Materials Needed to Build & Use:

  • 56 Quart Tub Minimum, larger is OK
  • Hole Saw (or something round & metal)
  • Blow Torch
    • Anything that will heat up the hole saw or your alternative choice will do but this is fast and easy!
  • Safety Glasses
  • Working Gloves
  • Hygrometer & Temperature Sensor
  • Spray Bottle
    • You can use any spray bottle, I just like heavy duty ones that donโ€™t stop working!
  • Perlite
    • 8 Quarts Does a 56 Quart tub to about 3-4โ€ณ ๐Ÿ‘Œ
  • Pillowcase
    • Optional, alternatives are a big strainer, screen etcโ€ฆ

How To Make A PolyTub

Itโ€™s pretty straight forward, I have tried several designs and configurations, I have tried with and without filter discs/tyvek/polyfill and have found in my years of growing that most gourmet mushrooms are sensitive to CO2 buildup. As our substrates are producing CO2 as they grow, and โ€˜breathing inโ€™ the oxygen, we want to avoid that buildup as much as possible to have more idyllic grows. With that said the filter discs proved to be useful only for tubs that are growing reishi antlers, and less suited for other mushrooms. Without the filters, the results knock your socks off!

Holes Holes Holes

Youโ€™ll want to create a 1โ€ณ-2โ€ณ hole about 2-4โ€ณ from the top of the tub on each of the short sides. I find using a tape measure and sharpie gets you nice even results, measure 4โ€ณ from the top and 4โ€ณ from the bottom, 4โ€ณ from either side and youโ€™re good to go. After the holes are made on the short side, youโ€™ll want to make the same sized holes on the long sides, but make these about 1-2โ€ณ above the intended perlite level of your tub and keep them 4โ€ณ from either side of the tub.

If youโ€™re using smaller holes, youโ€™ll want to space them evenly and add more to compensate. I had great success with 3/4โ€ณ holes made every 2โ€ณ at substrate level and 3 3/4โ€ณ holes made at the top on the short sides.


The EASIEST way to make the holes that I have found (DO NOT DRILL!) is to get your tools, PPE (gloves/eye protection) and materials outside. Carefully heat up the hole saw blade (I use pliers and gloves to hold it to avoid getting burned) and when itโ€™s good and hot use the hole saw to push through the plastic, voila.

Legal disclaimer: I mentioned safety a few times, so now if you get hurt itโ€™s on you ๐Ÿ˜‚

Avoid drilling because the plastic will break and you will be sad. In the past I have traced nice circles onto the tubs and heated up a scalpel, but this takes forever. Similar objects are sockets for wrenches but who wants to ruin their tools?

Setting Up & Using Your Polytub

Setting up your PolyTub is really simple. Add perlite, add mushroom fruiting substrates, and wait.

Get Your Pillowcase Ready!

I have found the pillowcase in the sink method to be the easiest way to soak the perlite before adding it to your tubs. Simply run water through it until the perlite is submersed, set it in the sink, step away for a few minutes and gently spin the pillowcase to wring out the pooling water at the bottom of the pillow case. Saturating the perlite is important as the perlite acts as your humidity reservoir, the air passing over it releases humidity and keeps your humidity levels in check. Humidity levels will vary from 85%-99% in the PolyTub in general, and I recommend a hygrometer to let you know if something is off.

Now Relax & Enjoy Them Grow!

In general, once youโ€™ve gotten your perlite soaked and your bags in the tub, you can expect 1-2 weeks of maintenance free, automated growing. Towards the end of your grow (depending on your home growing environment) you may still need to mist, but a good heavy mist (a mist, not a stream!) of the perlite will have you back in action for another week or two. I find that I can get through most grows with the initial soak and minimal (if any) misting near the end of the crop.

Wrapping Up

I have benefited from the use of PolyTubs for small scale grows of Oysters, Reishi (add filter discs for reishi!) and Lionโ€™s Mane for small scale grows. I hope this helps to simplify growing gourmet mushrooms for those with experience already, and to encourage those without experience to dive right in and get to growing!

As always we love all of the support and especially love a good question! Drop us a line and weโ€™ll be happy to help if you have any questions, comments or concerns! Email is always best, but drop a comment below if this helped you out or if you think we missed something!

Happy growing my friends, and good luck with your experiments!

Video From Our Friends 90 Second Mycology