How to Grow Your Own Oyster Mushrooms on Straw
by Dr Samuel Alexander, co-director of the Simplicity Institute and a lecturer with the Office for Environmental Programs, University of Melbourne.
I’ve been experimenting recently with growing my own oyster mushrooms, and as you can see from the photos, I’ve met with some success. I was motivated to explore mushroom cultivation partly because I’m a vegetarian and want to produce my own high-protein alternatives to meat; but I was also interested in using so-called ‘dead space’ to grow food (either inside or down the shady side of the house). Oyster mushrooms tick both these boxes, and they are also ridiculously tasty. Seriously.
Not only that, oyster mushrooms are extremely expensive when purchased from a supermarket, so it makes sense to grow them yourself. Currently in Melbourne they are going for $34 per kilo.
I’m no mushroom-growing expert, so do your own research, but below I’ve outlined how I’ve successfully grown my own oyster mushrooms on straw. It’s surprisingly easy, although you do need to take appropriate precautions to make sure you are growing the right mushrooms and in a hygienically safe way. Apparently white oyster mushrooms are the easiest variety to grow, which is why I started with them.
What you need:
- Straw (I used pea-straw successfully but I’m told wheat straw is better)
- Robust plastic bags, medium or large size (which can be reused)
- Oyster mushroom spawn (which I got from CERES in Melbourne and are also available here). You may need to find your local supplier.
- Spray bottle and water
My 10-Step Method:
- Before you begin, wash your hands and clean all your surfaces well. It’s very important to be hygienic when cultivating mushrooms, as you do not want to grow the wrong types of fungi! Good mushrooms are really good; bad mushrooms are really bad. Fortunately, oysters mushrooms are very distinctive.
- Once you’ve got all the materials, the first thing you need to do is pasteurise the straw. From my research online, I discovered that this essentially means heating the straw in water to around 70-75 degrees (Celsius) and holding it at that temperature for around 45-60 minutes. I used a large Fowlers cooking pot. Pasteurisation kills the bad bacteria but leaves the good bacteria. Before you put the straw in the pot, most websites recommend that the straw is cut up into small pieces, around 1 to 3 inches in length. (To be honest, I didn’t cut up my straw, and I still grew mushrooms, but perhaps if I had cut it up my production might have been greater — further experimenting required.)
- Once you’ve pasteurised the straw, take it out of the heating pot with tongs and let it sit in a clean tub while it cools down. Be careful as you’re dealing with a lot of hot water and the pot will be heavy. It’s important you don’t put the mushroom spawn into the straw until the straw is at room temperature otherwise you will kill the spawn.
- When the straw has cooled down, pack your robust plastic bags with straw quite tightly, and then distribute some of the mushroom spawn throughout the straw. I put about three or four pieces of spawn-covered dowel in each bag, but perhaps one would have been fine (further experimenting required). The straw should not be dripping wet, but it should still be damp from the pasteurisation.
- At this stage, sterilise a skewer or a nail (by pouring boiling water over it) and jab holes in the bags every 3 inches or so. This lets some air in, but not too much.
- You now have to find a home for you mushrooms. Keep them out of direct sunlight. They like some indirect light and I am told they like it best at around 15-20 degrees Celsius. (It’s been considerably warmer than that in Melbourne over the last two months, and mine have grown very well, but again perhaps the yields would have been greater had the temperature been cooler). More experimenting required. I kept my bags inside to minimise the risk of contamination.
- Now you wait while the mushroom spawn develops into mycelium and begins taking over the entire bag. Mycelium looks a bit like white furry cobwebs, and you should start seeing it develop in the first couple of weeks. It’s important that your bags of straw stay moist, but not dripping wet. I found that the water from the pasteurisation was sufficient to keep the straw suitably moist without needing to spray with water.
- After a number of weeks (depending on the size of your bags) the mycelium should have spread across the entire bag of straw. It is at this stage (which for me was about 5 weeks later) your mushrooms should start forming. I cut some slightly larger holes in the bag, although I’m not sure this was necessary. The mushrooms will decide that they want to grow out of one or more of the holes you’ve created, and they’ll usually grow in one or two clusters.
- Now comes the fun part. The mushrooms essentially double in size every day, so within a week or so you should have good-sized oyster mushrooms. Mist them with water two or three times a day over this period – again, not so they are dripping, just so they are moist. The mushrooms should be harvested while their rims are still curled over a little and pointing downwards. If their rims seem to be turning upward, it’s probably time to harvest.
- Harvest and eat. To harvest the mushrooms give them a twist at the base. This ensures that you leave the very bottom of the mushroom still in the bag. You want to leave that part behind as it is needed for the subsequent flushes of mushrooms. If you keep the mushrooms moist and in suitable conditions, you should get three or four flushes of mushrooms, although I’m told the first and second flushes are the most productive. I’m currently harvesting my second flush. When your bags stop producing, the straw can be used as mulch for the garden. (Alternatively, my understanding is that you can distribute some of your straw into new bags of fresh straw and the growing process begins again).
If there are any mushroom experts out there, do let me know if you have any advice, and if any of you decide to begin cultivating your own mushrooms, do let me know how you get on. I’m going to keep experimenting in the hope of developing the easiest and most productive methods.
That’s all for now. I’ve got to go cook me some shrooms.