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Autoclavable Mushroom Grow Bags

Autoclavable Mushroom Grow Bags

1 total reviews

Regular price $10.00
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Bag Size
Number Of Bags
Quantity

One bag failure in the steriliser can take out an entire batch. We source ours 30% thicker so it doesn’t.

Contamination is the number one enemy of every mushroom grower — hobbyist or commercial. The quality of your grow bag is the last line of defence between a clean colonisation and a bin full of green mould. Our polypropylene grow bags are built to 0.08mm thickness — 30% heavier than the 0.06mm industry standard — and fitted with a 0.2-micron filter patch for gas exchange that actually blocks contaminants rather than just slowing them down.

Four sizes. Six quantity tiers from 10 to 1000. Fully autoclavable and pressure-cooker safe. Tested on our own farm on Tamborine Mountain before we sell them to yours.

Which size is right for you?

Size

Dimensions

(cm)

Capacity

(KG)

Filter patch

(mm)

Best for Industry ref.
Small 13×12×45 1–1.5 38×38 Grain spawn, PF Tek jars, small fruiting blocks ~ Unicorn 14T
Medium Clear 20×12×50 2–2.5 38x38 All-purpose fruiting blocks, oyster, shiitake, lion’s mane, king oyster ~ Unicorn 3T
Medium Black 20×12×50 2–2.5 KG 38x38 Light-sensitive species, prevents side-pinning, cleaner aesthetics in fruiting chambers
Large 250×140×650mm 3–5 83x50 Bulk fruiting substrate, commercial blocks, high-volume production ~ Unicorn XLS-A

What makes these bags different

0.08mm polypropylene

30% thicker than standard

Most grow bags on the market are 0.06mm. The extra 0.02mm is the difference between a bag that survives a loaded autoclave run and one that develops micro-tears under heat and pressure — allowing contaminants in before colonisation even begins. Thicker walls also mean less risk of puncture during filling, handling and transport.

0.2-micron filter patch

The contamination barrier that matters

The filter micron rating is the most important spec on any grow bag — and most Australian sellers get it wrong. A 0.5-micron filter (the common alternative) allows particles up to 2.5× larger to pass through, including many mould spores and bacterial cells. Our 0.2-micron filter provides genuine protection while still allowing adequate CO² outgassing and O² exchange during colonisation.

Autoclave & pressure cooker rated

Rated to 121°C sustained

Food-grade polypropylene remains structurally stable through standard sterilisation cycles — 15 PSI / 121°C for 90–120 minutes. The bags won’t melt, warp or delaminate at the filter seam. Compatible with domestic pressure cookers as well as commercial autoclaves.

Gusseted base design

Stands upright when filled

The side-gusseted base gives the bag a stable footprint once filled, making it easier to handle during loading, sterilisation and inoculation. The bottom seal is heat-bonded for strength — no split seams under substrate weight or autoclaving pressure.

Clear polypropylene (and black option)

Monitor growth without opening

Clear bags let you observe colonisation progress, spot contamination early and time your fruiting transition without breaking sterility. Black medium bags serve a different purpose — blocking light to prevent unwanted side-pinning in species that fruit in response to light cues, giving you cleaner, more directional fruiting.

Scales from hobby to commercial

10 to 1000 bags per order

Whether you’re running a single pressure cooker grow or a commercial autoclave farm, we stock the quantities that make sense for your operation. Per-bag cost drops significantly at 500 and 1000, making scale genuinely affordable without committing to a full pallet from an overseas supplier.


What you’ll notice

  • Bags surviving autoclave and pressure cooker runs without deformation, split seams or filter damage
  • Faster, cleaner colonisation with fewer contamination events compared to lower-spec bags
  • Full visual monitoring of mycelium progress through clear walls without breaking sterility
  • Bags standing upright during loading — no collapsing, tipping or spilling substrate
  • Directional fruiting in black bags, with significantly reduced unwanted side-pinning
  • Consistent results batch after batch — the reliability that commercial production depends on

Why 0.2 micron vs 0.5 micron is not a minor difference: A micron (μm) is one millionth of a metre. Trichoderma spores — the green mould that destroys more mushroom grows than anything else — range from 3–5 microns in diameter. At first glance, both 0.2 and 0.5 micron filters block them. The problem is real-world filter performance, not ideal conditions. Filters are rated for nominal particle retention, not absolute — meaning a 0.5-micron filter may allow smaller particles, deformed spores, and bacterial cells (0.2–2 microns) to pass under positive pressure during bag handling or gas exchange. A 0.2-micron filter provides a meaningful additional safety margin, particularly important during long colonisation runs in non-sterile environments, or when your ambient contamination pressure is high.

And why thickness is a contamination issue, not just a durability one: Micro-tears in thin polypropylene — too small to see but large enough to bypass the filter — are one of the most common and least-diagnosed sources of post-sterilisation contamination. Extra wall thickness dramatically reduces the incidence of micro-tears during filling, handling and sterilisation. It’s not just about bags surviving the autoclave. It’s about maintaining sterility for the entire colonisation period.


How to use your grow bags

Loading → sterilising → inoculating → colonising

Loading & sealing

1
Fill the bag with prepared substrate or grain. Leave at least 8–10 cm of headspace above the substrate to allow for the filter patch position and a clean seal. The gusseted base will hold the bag upright during filling.
2
Remove as much air as possible before sealing. Flatten the top of the bag and fold it over, or use a heat sealer (impulse sealer) for the most reliable seal. Heavy-duty cable ties or bag clips work well for pressure cooker runs. Heat-seal above the filter patch, not through it.
3
Do not overcrowd your steriliser. Steam or heat must be able to circulate freely around every bag. Stacking bags flat can trap cool zones and result in under-sterilised substrate. Stand them upright or lean them against the walls of the vessel.

Sterilising

4
Pressure cook or autoclave at 15 PSI / 121°C for the appropriate duration.

Grain spawn

90–120 minutes at pressure

Bulk substrate (hardwood/straw)

60–90 minutes at pressure

5
Allow to cool completely inside the steriliser before moving bags. This is critical — moving hot bags creates a pressure differential that can draw unfiltered air through the bag walls or seal. Cool to room temperature (ideally overnight) before transferring to your still air box or flow hood.

Inoculating & colonising

6
Inoculate in a still air box or under a flow hood using grain spawn, liquid culture or agar transfer. For syringe inoculation, pierce the bag wall (not the filter patch) with a sterile needle — the polypropylene will self-close around small punctures, though self-healing injection ports offer greater reliability for repeated inoculations.
7
Colonise at species-appropriate temperature in a dark location. The 0.2-micron filter handles gas exchange passively — no additional FAE (fresh air exchange) is required during colonisation. Monitor through the clear walls for signs of healthy white mycelium and watch for any green, black or orange contamination, which indicates a failed batch.

Choosing your quantity

Per-bag cost drops at every tier — order for your current operation, not just this grow.

Quantity Who it’s for
10 First-time growers, single-species trial runs, testing a new substrate mix
25 Regular hobbyist growing 1–2 species, small kitchen grows
50 Serious hobbyist with a dedicated grow space, running multiple species simultaneously
100 Semi-commercial grower, local market or restaurant supply, consistent monthly production
500 Established commercial operation, multiple autoclave runs per week — meaningful per-bag savings
1000 High-volume commercial farm — lowest per-bag cost, stock for 3–6 months without reordering

Storage

Store unused bags flat, in a cool dry location out of direct UV light. Prolonged UV exposure can degrade polypropylene and compromise the filter patch adhesion over time. Bags are pre-sealed in packs — keep the pack closed until needed. No special conditions required; a shelf in your grow room or storage area is fine.
💡 Tip: If you’re storing 500 or 1000-bag orders, keep them in their original packaging to avoid dust accumulation on the filter patches before use.

Full specifications

Material Food-grade polypropylene (PP)
Wall thickness 0.08mm (30% thicker than industry standard 0.06mm)
Filter rating 0.2 micron (μm) — all sizes
Filter patch size — Small 38×38mm
Filter patch size — Medium 38mm × 38mm
Filter patch size — Large 83mm × 50mm
Temperature rating Sustained 121°C / 15 PSI (autoclave and pressure cooker safe)
Base design Side-gusseted, heat-bonded bottom seal
Sealing method Heat sealer (impulse sealer), heavy-duty cable ties or bag clips
Available quantities 10 / 25 / 50 / 100 / 500 / 1000 bags per order
🏭

Scaling up your mushroom farm?

We offer wholesale pricing and bulk quantities for commercial cultivators across Australia. Whether you’re running a weekly autoclave schedule or planning a new production facility, get in touch to discuss custom quantities and pricing.

Contact us for wholesale →

The Kai Kai Farm story

We didn’t start selling grow bags because we found a cheap supplier. We started selling them because we couldn’t find bags good enough for our own production on Tamborine Mountain — and once we sourced them, other growers started asking where they came from.

Every batch we stock goes through our own growing operation first. We run the same bags through our autoclaves, fill them with our own grain spawn and substrate, and colonise them in our own fruiting chambers before they end up in your hands. If a batch doesn’t perform on our farm, it doesn’t go on the shelf.

Founded by Quintin and Amy in the Scenic Rim, Kai Kai Farm supplies hobbyist and commercial growers across Australia. When you buy our bags, you’re buying what we trust in our own production. That’s the only standard we’re interested in.

Why Customers Love Us

  • Australian Owned
  • Family Business
  • Sustainability
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