Now that we’ve been mushroom farmers for a whole three months I thought I would do a post about bags for growing oyster mushrooms and what we’ve learned so far.

When we started we bought a whole stack of filter patch bags thinking they would be just the right thing since the mycellium would be able to breathe through the patch without becoming contaminated. What we found was that the mycellium grew really well by the patch but the rest of the bag never quite got colonised. You have to poke holes in the bag to get decent colonisation which seemed to kind of defeat the purpose of the patch since contaminants would just enter through the holes…  We saw people using these bags for colonisation then pulling them off for fruiting but for us here is SA it is just way too dry for that to be an option. All the primordia just dried up when we tried that.

We've ripped off the filter patches to allow the mushrooms to bloom. I'm cutting holes in this bag to allow the mushrooms to push out. Colonisation in the rest of the bag is patchy.

We’ve ripped off the filter patches to allow the mushrooms to bloom. I’m cutting holes in this bag to allow the mushrooms to push out. Colonisation in the rest of the bag is patchy.

Next up were pre-punched clear bags – good for beginners because you can see if there’s contamination but plenty of air for oyster mushroom primordia to know where to fruit from. These were definitely an improvement but the thing with oyster mushrooms is that they like the light. So primordia will form where there is access to light even if there’s no hole. With these bags we got stacks of primordia forming inside the bag which were generally a bit mutant by the time we’d cut open a hole for them to grow from. Plus the bunches which did form were quite small – maybe because there were so many primordia forming because of the light factor.

We got better results with these but had lots of baby mushrooms trapped under the plastic!

We got better results with these but had lots of baby mushrooms trapped under the plastic!

A black pre-punched bag was the next trial. When these ones fruited we started to think we might actually be getting the hang of things. We got much bigger bunches, more even distribution and more clusters coming on at the same time. We also got better flushing. Even though we were still beginners and we couldn’t see if there was mould inside we figured we could make a spy bag (a la Tradd Cotter) to check for contamination rather than doing the whole lot in clear plastic.

We got our first third flush mushrooms out of the black bags.

We got our first third flush mushrooms out of the black bags.

Finally, inspired by photos in Organic Mushroom Farming and Mycoremediation and a (cheesy) video we watched about Mepkin Abbey (of all places) we decided to try the giant sausage (or dune worm) bag. It’s the same thing as the short pre-punched black bag except you buy it in a roll and punch the holes yourself. The long bag is cheaper and faster than the other types of bags we tried and we can maximise the vertical space we use in the grow room. We’ve been punching a hole in the bottom to make sure excess water can drain away (we had one where it got a bit boggy inside and everything went mouldy…). So far the only downside is that you need two people to manhandle the bag into the grow room and tie it up. But it’s a small down side given how much more substrate we can fit in there compared to smaller bags.

Chris is stuffing inoculated straw into this tube of bag. It will be about 1.8m tall once it's done.

Chris is stuffing inoculated straw into this tube of bag. It will be about 1.8m tall once it’s done.

There will be more adaptations I’m sure. But so far this is the best one so we’ll work with that for the next little while.

 

 

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2 Comments

Anson · December 10, 2018 at 4:37 am

Thanks for the review. I’m looking into trialing hanging some inoculated bags to up the CO2 levels in my caterpillar tunnels next season. Concerned about light/heat, and moisture retention in a pre-punched bag. With CO2 being heavier than the surrounding air, it’s important to hang the bags above the plants. Any recommendations on which bags you think might be appropriate?

Also brainstorming ways to hang the bags where they’d be protected from direct sunlight. Some sort of umbrella-like shield.

Looking at any mushroom fruiting as a secondary benefit.

    chris · December 20, 2018 at 2:56 pm

    Hi Anson,
    We have no experience growing mushrooms in the outside environments except when we hung some pink oyster in the microgreen hoop house and they just cooked and went mouldy. The bags we use are just black LDPE 300mm 80micron Layflat tube which we cut into lengths and punch holes in with a blade. We cut 1000mm lengths, tie off one end, fill then tie off the top with a cable tie. We punch 24 holes evenly along the length. This number of holes we have worked out is optimum (450mm length stuffed and tied bag) for spawn run speed and cluster size for our markets (restaurants).

    Your other ideas sound like a lot of effort for maybe not much return. We’ve tired all sorts of things and we find that before doing anything now we ask ourselves “Is this addressing our weakest link in our business?”. A CO2 generator might be the easiest way to get CO2 into your catepillar tunnels?

    Happy growing!

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