Bulk growing

Materials Needed

• Plastic Tote: 54qt - 66qt Sterilite (Clear base, latching lid preferred).
• Drill & Hole Saw: 2-inch (5cm) hole saw bit.
• Black Spray Paint / Liner: Heavy duty trash bag (black).
• Filters: Polyfill OR Micropore Tape OR Adhesive Filter Discs.
• Ruler & Marker: For measuring hole placement.

1

Marking the Holes

Proper airflow is physics-based. We need low holes for CO2 to exit and high holes for fresh air to enter.

[Diagram: Side view of tub showing 2 low holes on long side, 1 high hole on short side]

• Long Sides (Length): Mark 2 holes on each long side. They should be just above where your substrate level will be (approx. 4-5 inches from the bottom). Space them evenly.
• Short Sides (Width): Mark 1 hole on each short side. This should be high up, near the handles/lid.

2

Drilling

Drilling plastic can crack it. Take your time.

• Run the drill in REVERSE first to score the plastic and melt through slightly. This prevents cracking.
• Once scored, switch to forward and apply gentle pressure.
• Clean up the plastic burrs with a knife or sandpaper.

3

Applying the Background (Liner)

Mushrooms love to grow on the sides where the substrate shrinks away from the tub (side pins). A liner prevents this.

• Cut a black heavy-duty trash bag to fit inside the tub.
• It doesn't need to be taped to the tub. The weight of the substrate will hold it.
• The liner should move with the substrate as it shrinks, preventing the micro-climate that causes side pins.

4

Filters

Now we need to filter the air moving through those holes.

Option A: Polyfill (Classic)

Stuff the holes with polyfill (pillow stuffing). Pack the bottom holes TIGHT (to restrict airflow slightly) and the top holes LOOSE (to allow heat to escape).

Option B: Micropore Tape (Modern)

Cover holes with 1-2 layers of 3M Micropore tape. It's cleaner and easier than polyfill.

Option C: Adhesive Filter Discs

Buy pre-made filter patches and stick them over the holes. Professional look.

5

Unmodified Tub? (The Debate)

Some growers ("Bods Unmodified Tek") skip drilling entirely.

They simply flip the lid upside down to create a small gap for air. This works well but requires more manual tuning (adjusting the gap) depending on your room's humidity.

Recommendation: Build the modified tub (drilled) for your first time. It's more "set and forget".

← Back to Monotub Guide