Making a Monotub for Mushroom Cultivation

Part 1 : Unit 5 : Making a Monotub for Growing Magic Mushrooms

What is a Monotub?

A monotub is a type of container used for growing mushrooms, particularly species that benefit from high humidity levels, such as shiitake, oyster and Cubensis.

The monotub is typically a plastic tub with a lid. The sides of the tub has several holes cut into it, which are then covered with a filter material to allow for air exchange while keeping contaminants out. This provides a perfect environment for our mushrooms to grow later on in the process.

Constructing your DIY Monotub

You will cut out 8 holes in your 40 quart tubs (full list of items can be found in the “Cultivation Shopping List” page) and then cover them with heavy duct tape. The holes are placed in specific areas on the sides of the tub, to allow better air flow.  Cutting these holes requires patience and attention – and using our DIY method, also involves fire 🔥. Make sure to be slow and mindful with this procedure and pay attention to every step. Let’s get to it!

Making a monotub
Building A Monotub

Building a DIY Monotub for Growing Mushrooms

Items needed
Notes & Tips
Making a monotub
Items Needed To Make A Monotub

Video Tutorial : Building a Monotub for Growing Mushrooms

Step 1 : Mark Air Vent Hole Positions on the Tub

Rinse and clean the monotub if needed, and place it right side up on your work surface or table. Draw a line about 3 inches high from the bottom of the tub. (Later, when you put your bulk substrate and grain spawn into the monotub, this line will help you level out the mixture so that you get an even thickness throughout your mycelium cake.) Next, mark 3 holes on the each of the broad sides of the plastic tub, where the middle hole is lower, as shown on the diagram to the right.  

Monotub fae hole positions

Step 2 : Heat Aluminium Can and Punch out Holes on sides of Tub

Grab an empty coke can and optionally, remove its top with a can opener. Get a good grip of the can from its bottom side using pliers, and heat up the top of the can for a minute or two on a gas burner with high heat.  Gently push the can top against one of the hole marks on the tub, and then lightly twist the can. The can doesn’t need to go through the plastic entirely, but just enough for you to be able to push or cut the remaining plastic around the hole later on, without too much effort. 

Re-heat the top of the can and proceed to cut through the rest of the holes around the tub. Plastic residues on the can may go up in flames when heated, so be careful of the fire, and of molten plastic dripping off the can. Once all the holes are completed, use a knife to carefully smoothe the edges of the holes from and remove any protruding plastic bits. This will provide a smooth surface for the gorilla or duct tape you are about to apply on the holes.

Step 3 : Cover Holes with Gorilla or Duct Tape on both sides.

Proceed to cover up the holes with wide gorilla tape or duct tape, on both the outside and the inside of the monotub. Make sure the holes are covered well, with an overlap,  so there are no air gaps between the tub and the tape.

Next Unit: Using a pressure cooker. The core tool of your mushroom cultivation journey, a pressure cooker. Dangerous if not used correctly or mishandled. Make sure you totally understand the next module.

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