I’ve been posting this on reddit, so forgive me if you’ve already read about it…
I have long had an interest in trying to grow my own mushrooms, but recently started doing a lot of reading to learn the process. I had intended to start out growing a couple types of oysters on cut straw, but while I was collecting supplies and waited for spawn to arrive I ran across an article talking about cutting up clean cardboard, boiling it to sterilize, and seeding it with chopped mushroom stems. I figured this would be a great way to practice and see how much contamination I would get.
Besides the oysters, I wanted to also try cremini/button mushrooms. One of the local grocery stores has them in a bulk bin which appears to not be processed, and it allowed me to pick out some that looked like they came straight from the ground with obvious signs on mycelium still on the base. Great! So I set everything up, drilled some air holes in a small food container, added the cardboard and stems, and put it away in the closet. And then a couple days later I read that creminis actually want a rich mixture of manure and/or grain to grow on. Well crap…
The point was still to watch for contamination though, so I let it continue. A week passed without contamination and I was happy that it appeared I had cleaned things pretty well (and we’re talking a very hasty setup on my kitchen countertop in open air). On Sunday, I spotted some white fuzz. Oh boy, this could be it, the experiment is almost over. But then I checked on Monday… and it’s not just fuzz, I have actual STRANDS growing across the cardboard. Could it be?!?
Well, today it’s still looking pretty promising, and I’m seeing more coming out from various points in the cardboard. It’s hard to get a good look at everything because of the humidity, but today is day 12 since I set up the container and there are no greens, blues, or reds anywhere. I am hopeful, although frankly amazed at what seems to be happening.
In the meantime my oyster spawn arrived but it was less than expected so I have picked up some quart jars and am waiting to receive some rye grain. I have blue and pink oyster spawn which I will split between two jars each to expand before trying to move it to grow bags with straw. It will take a little longer than planned but I’ll get there. And I’m waiting for my container to be fully colonized with the unexpected spawn (or to see a definite sign that it is NOT mycelium) and then I’ll get that transferred to a grain jar as well.
However it goes, I’m having fun!
OK I’ll play around and see what I can make work. Considering I seem to be having good success with the cremini spawn (which was literally just bringing the cardboard and water to a boil and then laying out on the countertop to cool down for about 30 minutes) I’m hopeful that I can pull this off too. I live near Denver Colorado so we’re quite high with a pretty dry climate usually, but we’ve been getting a LOT of rain this Spring so I figure the risk of mold spore is a lot higher that normal.
Anyway thanks for all the advice! Hopefully will be posting pics of some nice grain spawn in a few weeks!
A cheap and easy method for expanding spawn is Lipa’s Tek. Renegade Mushrooms goes over the method in this youtube video: https://www.youtube.com/watch?v=HD_k-dAyE5Y
Basically a 40 pound bag of Hardwood Fuel Pellets (make sure they’re hardwood) can go for around 6-7USD. If you’re in a pinch, want a specific species of tree, or want certified organic, you can find hardwood pellets for smoking meats that go for somewhere around 0.50USD/lb in 20-40lb bags.
The reason this method works is that fuel pellets have less sugars and starches, and they are already partially pasteurized in the pellet press. So, as long as your pellets are stored well, a two-hour pasteurization at 200F is more than enough to get rid of most of the competing organisms. This is especially true of Pleurotus sp. (the Oysters), and from what I’ve heard, Hericium sp. (Lion’s Mane, etc), but I’m currently waiting on some Pholiota adiposa (Chestnut) to fruit that seemed to do well in pasteurized HWFP.
Give it a try, it’s a lot cheaper in terms of dollar cost, energy use, and time than wet-sterilizing in a small Pressure Cooker–but it’s best for expanding from spawn into more spawn or for bulking. You won’t get the same sized flushes as with something like grain or Master’s Mix, but you can easily whip up a lot more substrate–so it all comes out in the wash. I just retired 6 spent bags of P. ostreatus and they all seemed to do pretty well, and fruited more than once.
Nice, I’ll have to check out the video after work, but I’ve heard of using the hardwood pellets and there’s plenty of places around here that sell supplies for smokers. Once I get something going for my current spawn, lion’s mane is the next thing I want to try out. I just got my oyster starts transferred to grain jars yesterday so I’m making slow but steady progress.
Although now I think maybe I’m confusing the terminology? For mushrooms, does “expanding” refer to the process of growing out the spawn so you have a suitable quantity on hand, or is that the final stage of growing the spawn in fruiting containers? I’m currently at the stage of taking a very small amount and growing it out so I have enough on hand to get fruiting bags of straw started.
When I use the word “expanding”, I am referring to “increasing in volume”. So you could just “expand your spawn” (making more spawn), or “expand to bulk” (inoculating your fruiting blocks). Oh, and definitely try to find actual fuel pellets if you can, they’re usually much cheaper per pound than food-grade BBQ smoking pellets. I have found the basic fuel pellets at stores like Tractor Supply Hardware, but you have to ask an employee to check the stock in the back (since they’re out of season).
If you do end-up buying hardwood smoking pellets, be wary that some smoking pellets can contain additives like molasses, which means too much sugar for basic pasteurization with Lipa’s Tek–so always check the ingredients with smoker pellets.
You may be seeing pics faster that I expected! It’s been two days since I transferred my original spawn samples to the grain jar, I checked them today and the mycelium is already starting to spread to the grain. I was really expecting to need at least a week or more before I saw any definitive growth, so apparently they are happy.
I do have one jar of popcorn I am concerned about though. That one has little white dots all over the kernels throughout the jar, while all the other jars the kernels are still nice and clean. I’ll be watching that one closely to see what happens, although I’m not sure what would have caused contamination in that particular jar. It wasn’t even the last jar I loaded up. Maybe I’m getting worried over nothing, but I’m sure I’ll probably know in a few more days.
Considering this nice growth, I think I’m going to go ahead and transfer my cremini spawn to its grain jars this weekend. I’m getting nervous that the longer I wait, the greater the chance of getting some contam through the air holes.
You may be seeing pics faster that I expected!
Great!!
That one has little white dots all over the kernels throughout the jar
Hmm, that is suspicious. Did you inoculate using a liquid culture? If you spread the liquid culture throughout the grains, it could look like that… But if your inoculant is more localized (spawn, agar, or tissue) and the whit spots appeared all over the grain, you might not be so lucky 😰
