How to grow shrooms in bulk monotub tek, and how to build a monotub. Need spores? Please support our sponsors! For mushroom spores visit sourceofspores.com Coupon code "shroomology" gets you a discount on your entire order. NO MISTING AND NO FANNING ALLOWED! Update April 2018: A grow kit has been made for this tek, if you want to skip all of the hard labor of creating and sterilizing your own grain spawn and substrates, and have someone who has been doing this tek for more than 10 years make it for you, order the grow kit here from Mycology Kits online store: https://mycologykits.com/shop/grow-kits/monotub-bulk-substrate-fill-kit/
SECTION 1 Monotub Design:

These designs are for the STERILITE 60 QT, but apply to any tub you have, with some modification on your part.

There are several designs for monotubs. If you get a tote that is larger or smaller, than the sterilite 60qt, and you plan on using my sub prep method, you will have to increase/decrease everything in this tek accordingly, and may need to add weather stripping to the lip of the tub so that there are not any gaps, creating too much FAE.

These monotubs will have about, a 4 1/2" deep substrate if you follow my substrate prep contained herein.

Cased Sub Monotub Design:
This design is very simple, but the hole placement is key here for optimal evaporation from the casing layer, and surface of the sub, while maintaining proper RH. The hole placements will be large 1" x 1" holes up top, and small 1/4" holes in the bottom of the tub. "Bottom" meaning 5" above the bottom of the tub.

There are many ways to cut the large holes in the top of the tub. You can use a spade bit, a dremel cutting bit in a regular drill, a hot knife, or a soldering iron. Be creative and know that all the ways i mentioned except for the knife are efficient.

The small holes I use a 1/4" drill bit and a drill to drill the holes around the bottom.

Make the bottom holes about 1" to 1 1/2" apart from each other.




Section 2: Monotub Sub Prep:

You can use whatever substrate you like in your monotub, but this is how I do it and it is VERY simplified.

Things you will need:

5 gallon bucket
large tote (for mixing sub in not the monotub)
1/2 brick of Coco Coir
Pot to boil water in
6 qts COARSE grade vermiculite
4 qts cmc/HPOO (Cow manure compost/ Horse Poo)
Hydrated/Pickling lime
8 cups of water.
Large oven bag
16qt(or larger) Pressure cooker
Coco Coir can be found in Petsmart or any pet store that sells reptiles. It is used for reptile/arachnid bedding.

Bring 8 cups of water to a boil.
Cut brick of coir in half
Put coir in a 5 gallon bucket
Pour boiling water over coir
cover with the bucket lid or a towel for 15 min
stir coir up so that it is all broken up, evenly distributed, and fluffy
Allow coir to sit for 1 hour, covered, to hydrate fully.

While the coir is cooling, move to the next part of sub prep

Pour 4qts of cmc/Hpoo into a large tote for mixing.
Add 2 TSP of lime (to buffer PH of poo and coir. it is required for multiple flushes).
Mix as well as humanly possible.
Add 6 Qts of COARSE grade verm. (YES it must be coarse grade)

mix well again.

After the one hour cool time for the coir, dump the entire contents of the 5gallon bucket into the large tote.


Mix well


This mix should come out to perfect field capacity (moisture content is key here). Field capacity is when you can grab a handful, squeeze it and a little water can bead up at the knuckles but should not be dripping. When you losen your grip the substrate should remain in the collapsed form.

This is close to field capacity, a bit too wet IMO, but will work ok. If your sub is any wetter than this, you will nee to add verm to it until it is field capacity. One little drip due to gravity is ok though.


If your sub meets these requirements, load it into an oven bag, squeeze the air out (you can compact the sub in the oven bag) and seal the bag with the seal tie that came with the bag.

poke two small holes in the top of the oven bag
cover holes with micropore tape
tape down any excess of the bag to the main body of the bag. This is to prevent the excess from clogging the rocker pipe of the pressure cooker.

Pressure cook the substrate for 90min @ 15PSI

Let cool in PC overnight.

Section 3: SPAWNING TO THE MONOTUB

Things you will need:
6 qts spawn
Black Trashbag (preferably contractor or yard)
Micropore tape
Aluminum Foil
Polyfill pillow stuffing
Isopropyl Rubbbing Alcohol

Line the tub with the black trash bag. I just put the whole thing in there.


Dump the whole oven bag of PCed substrate into the trashbag lined tub, making sure not to get any behind the trash bag (you can tape the bag up to the walls of the tub if you need to).

Dump all your spawn on top of the sub.


Mix very well making sure to get along the edges, and especially in the corners of the tub.
Make sure to make the sub as flat as possible without packing down the sub. it is okay to pack it just a little bit to make the surface flat, but not very much at all is ok. Use very little force. (being flat will ensure a good probability of an even pinset)

Once that is done line the sub with foil, poke a few holes in the foil, and cover them with micropore tape.


Cover the bottom holes with micropore tape, and stuff tight balls of polyfill into the top holes, so that they dont come out easily.

Put the lid of the tub on and incubate @ 80-82* F for 10 days. It does not matter if there is light or not.

Section 4: FRUITING

After the 10 days colonization period, you can bring the tub out to fruiting conditions. To do this remove the foil, cut the trashbag down below the bottom holes (this works best with a utility knife, or exacto knife)

Apply a casing layer of your choice (I prefer 50/50+ or just regular 50/50) that is between 1/4" - 1/2" deep.

Make sure that the casing is porus not a flattened mat, and not over field capacity.

Mist the walls of the tub.

Put the lid on.

Set in an area where there is natural ambient lighting (NO DIRECT SUNLIGHT)

Temperatures between 68-72*F are optimal for this tek.

In the fruting area there should be a  fan to circulate air, making for a good slow even FAE rate inside of the monotub.

Depending on your strain of choice it can take between 5-14 days for pinset.

No Misting, No fanning.