"Mark 1" Mushroom Monotub (Microppose)

Mark 1 Mushroom Monotub by Microppose

The Mark 1 Mushroom Monotub is a purpose-built cultivation chamber made from durable PP plastic, designed to give your bulk mushroom grows the stable microclimate they need to fruit properly. Measuring 12" x 12" x 12" (roughly 30 x 30 x 30 cm), it sits neatly on standard steel wire shelving while still holding enough substrate for genuinely satisfying flushes. Available in three sizes — Small, Medium, and Large — so you can match the tub to your grow space and ambition.

Why a Dedicated Mushroom Monotub Matters

A monotub is the simplest reliable method for bulk mushroom cultivation at home. The concept is straightforward: a sealed container that holds your colonised substrate, maintains humidity around 90-95%, and allows controlled fresh air exchange during fruiting. The Mark 1 does all three without requiring you to build anything from scratch.

We've seen plenty of growers start with modified storage bins from the hardware shop — holes drilled with a spade bit, polyfill stuffed in as makeshift filters, lids that never quite seal right. It works, sometimes. But the failure rate from contamination is noticeably higher. The problem isn't the concept; it's the execution. Rough-drilled holes leave plastic burrs that trap moisture and bacteria. Ill-fitting lids create uneven humidity pockets. Polyfill compresses over time and stops filtering properly. The Mark 1 solves these issues by giving you precision-cut 2" air holes, a clip-lock seal that actually holds, and a lid with genuine optical clarity — not the cloudy translucence you get from a cheap storage box.

The PP plastic deserves a mention too. Polypropylene is autoclave-safe, meaning you can sterilise this tub properly between grows without it warping, cracking, or leaching chemicals into your substrate. Pick it up and you'll feel the wall thickness — this isn't flimsy stuff. It's the same grade of plastic used in laboratory containers, which is exactly the mindset you want when growing mushrooms: treat it like a lab, get lab results.

How to Use the Mark 1 Mushroom Monotub

1. Sterilise everything. Wipe down the entire interior of the Mark 1 Monotub with isopropyl alcohol (70% concentration works best — 99% evaporates before it finishes killing surface contaminants). Wear gloves. We've seen growers lose entire batches to one ungloved hand touching the inside of a tub.
2. Line the tub. If you're using a Microppose Small Monotub Liner, press it into the base and up the sides. The liner prevents side-pinning (mushrooms fruiting between the substrate and the tub wall, where they grow stunted and weird) and makes disposal after your final flush a 30-second job.
3. Add your colonised substrate. Whether you're using a ShroomTek All-In-One Grow Bag or your own grain-to-bulk mix, spread the colonised substrate evenly across the base. Aim for a depth of 3-5 inches (7.5-12.5 cm). Microppose recommends a grain-to-substrate ratio that fills the tub without packing it tight — the mycelium needs air pockets to breathe.
4. Seal the air holes. During colonisation, plug the 2" holes with Monotub Hole Plugs to maintain high humidity and CO2 levels. The mycelium thrives in this enclosed environment. Keep the clip-lock lid firmly closed.
5. Wait for full colonisation. This typically takes 10-14 days depending on species and temperature. You'll see the surface turn white as the mycelium network spreads. The high-clarity lid lets you monitor progress without opening the tub — and opening the tub during colonisation is the number one way to introduce contaminants.
6. Switch to fruiting conditions. Once the surface is fully colonised, remove the hole plugs and apply Adherable Monotub Filters over the 2" holes. These allow fresh air exchange (FAE) while filtering out airborne contaminants. The CO2 drops, oxygen rises, and the mycelium gets the signal to start producing mushrooms.
7. Maintain and harvest. Mist the inside walls (not the substrate directly) if humidity drops. The clear lid lets light through — mushrooms need some light to orient their growth upward. Harvest when caps begin to flatten but before spores drop. You can expect 2-4 flushes from a single tub before the substrate is spent.

Honest Limitations — What the Mark 1 Won't Do

The Mark 1 is a tub, not a complete grow system. It doesn't come with substrate, cultures, liners, or filters (unless you opt for the Medium or Large package). If you buy the Small variant expecting a ready-to-grow kit, you'll be disappointed — it's the bare chamber only. Make sure you've got your consumables sorted before your tub arrives.

The 12" x 12" x 12" size is also a deliberate trade-off. It's compact enough for a shelf, a cupboard, or a small closet, but it won't produce the massive harvests you'd get from a full-size 66-litre monotub. If you're growing for personal use and want 2-4 modest flushes, the Mark 1 is spot on. If you're trying to fill a dehydrator every week, you'll need multiple tubs or a larger setup. That said, many growers we've spoken to prefer running 3-4 smaller tubs over one large one — if one tub contaminates, you don't lose everything.