Growing Oyster Mushrooms in a Subtropical Climate

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My mushroom journey has been an interesting one. You may have remembered my Feb year of fear challenge was to approach coffee shops for their used grounds in an attempt to grow my own mushrooms. That failed. Not the asking, just the grounds. 

Nerding out with many experiments in the first couple of months!

I won't rule out coffee grounds as a lovely medium for growing mushrooms, it's just that contamination with mushrooms is an issue and although the grounds should be fairly sterlised after being steamed, there's still quite a few variables when you ask blindly from a cafe. Not the cafe's fault, just it's important to try to reduce your variables as much as possible for a successful harvest. On a side note, the grounds felt so lovely and I can see why people love using them for other things like mulch for their gardens!

Bad mould - gross!

I read and watched many many mushroom growing tutorials and I have a sneaky suspicion what works for one person may not work for the next and I'm guessing the climate you live in is a big factor. So this post is to share some ideas and encourage some personal experimentation!

My very first growing attempt - a bought kit from mountain top mushrooms!

You will need to buy your mushroom spawn for the right season but you'll also need to experiment with fine tuning your method for the atmosphere you're growing them in. If you were doing it on a commercial scale the most sense would be to have a completely controlled climate warehouse. 

So below is what worked for me who lives in QLD, Australia (in a subtropical climate) during summer. I've started with oyster mushrooms because they're meant to be relatively easy :) My Dad and I have been on this journey together swapping tips and tricks and it's been a fun little geek out!

Produce from mountain top mushrooms - they know there mushrooms! Nice to support local farmers too!

GROWING MEDIUM

Sugar cane mulch – tick, tick, tick. It's cheap, it's a by product from the sugar cane industry and it's easy to find organic options as that crop is very hardy and often doesn't require pesticides.  I'm lucky that QLD is a sugar growing state.

STERILISING THE MEDIUM

My dad has had luck with steaming the mulch. I don't have the proper set up to steam, so I've relied on boiling. I've experimenting with boiling the mulch for an hour but 30 minutes seems to be fine as well. If I get serious with mushroom growing I'm going to invest in a different set up because this stage is the most messy & time consuming part - my kitchen looks like a bomb exploded in it afterwards!

the bucket method

CONTAINER

Buckets, with alternating big and small holes drilled around the side. I bought my bucket from my local fruit and veg shop and marked out the holes and drilled away. My Dad has had success with growing his in plastic bags with cotton wool on the top and then once the mushrooms started to appear he removed the bag altogether as you can see below. You can also see all the white mycelium taking over the straw, you want this to happen!

Dad's method (the straw needs re-soaking after the first harvest as it dries out quickly!)

CONTAMINATION (my biggest issue!)

My first attempts I assumed failed when I spotted green mould growing on the sugar cane, I freaked out and threw everything out. If you see some green mould, don't freak out just remove it. You  ultimately want the mushroom mycelium to overtake the straw and nothing else.

Thoughts to prevent the unwanted mould in the first place.

Cover the holes up! I covered the small holes with sticky tape and the big holes with cotton wool. The idea is that you want some air flow but to limit contaminates entering. You also need to make sure your bucket/workplace/hands/equipment are all sterilised when you're pepping your mix. Fill your bucket right to the top with your mulch/medium. The mould seemed to gravitate more towards the larger piece of the cane mulch. I'm going to experiment more with this but for now, my plan is to remove any large segments of mulch at the beginning.

Make sure you check your mix 4 -7 days to keep an eye on any potential mould and if you see any remove it! 

PROCESS

MIX

The mix is simply your medium (cane mulch for me!) mixed with some mushrooms spawn which my Dad bought online from here and kindly split his batch with me. You don't need a lot of spawn, but just follow the instructions that come with your purchase.  I think they say 10% of spawn to your medium but I used less than 5% and had success. I also didn't worry about being super precise with the ratio!

LEAVE
Ideally your mushrooms want to live in a room with high humidity and no direct light.  My bathroom ended up being perfect :)

SPOTTING MUSHROOMS

You should see some tiny pin heads 2-3 weeks after you first make up your mix. 

When the pin heads appear, remove the tape and the cotton wool (carefully!) from the outside of the bucket. The mushrooms should have successfully dominated the mulch so letting in air isn't such a worry any more, plus at this point you need to start spraying your mushrooms with water. I just used an empty spray bottle and gave the outsides of my buckets a spray every day (more if I remembered!). I also lifted the lid (every few days) and sprayed the mulch directly just to keep everything nice and moist. The one issue with the cotton wool is you can risk pulling off all the tiny pin heads with it so be gentle!

HARVEST

Once the pin heads appear the mushrooms will grow to full size with 3-4 days (keep spraying with water). It's incredible to watch just how quickly they grow at this point. You know they are ready for harvest when the outside lip starts to curl back over. If that visual is confusing (it was for me at the start) the mushroom's edges will eventually start to go brown and although still find to eat, it's like watching a banana ripen - you want to eat it at the perfect time! When the mushrooms are ready, cut them off at the base with a knife or scissors and store them in a container in the fridge. They last at least a week in the fridge, maybe more, I just eat them too quickly to know! Oh and once one of the mushrooms starts to curl back over (even if they others on the cluster are much smaller) you need to harvest the lot.

Your bucket should fruit another time and maybe a third! This will take around 2 weeks before you start seeing the tiny pin heads again. I've found continuing to keep the buckets moist with the water spray bottle worked in successfully growing a subsequent harvest.

I'm still learning and I'll add to this as I gain more knowledge and of course if you have tips please share them!

Aren't they super pretty!

2020 Update: I've since been sterilising my cane mulch in a lime bath, just a few scoops of lime in a big bucket of water with the mulch and left for 12-24 hours (covered) outside.  I use some PH strips (I bought cheaply off ebay) to check my lime amount was okay.  This method has so far led to zero percent mould, so I'm going to continue with it.

At the end of 2019 into 2020 Australia suffered amazing amounts of bushfires which was caused by very dry weather, dry weather = low mushrooms yields and I learnt the importance of keeping the humidity up for my mushrooms with my spray bottle especially in the stage where you start seeing the little pin heads form (and even before that).