This was inspired by a workshop at the 2016 Radical Mycology Convergence “Easy Non-Sterile Oyster mushroom Bag Cultivation Workshop” done by Cornelia Cho, president of the Mushroom Club of Georgia. I went home with a small bag of elm oyster spawn on “Yesterday’s News” kitty litter (unused) enriched with guinea pig food. A couple months later it sprouted elm oyster mushrooms (see photos). They were delicious! More information on this technique can be found here.

Rather than waiting to see if there would be a second flush of mushrooms. I decided to use the contents of the bag to inoculate wood pellets enriched with guinea pig food in a five gallon bucket. This proved successful, so I wrote this instructable. As in another instructable by me, oyster mushrooms simplified, I used hydrogen peroxide (One-Step) as a pasteurizing agent. It worked well here. It’s easier than hot water or steam treatment and probably more consistently reliable than doing without pasteurization.

Step 1: Materials

2 five gallon plastic buckets

Plastic tub - for mixing the ingredients

Drill - to make holes with ½” spade bit

½” bit

Paper towels

Rubbing alcohol – either 70% or 91% works

Disposable rubber or plastic gloves.

Pellet fuel - This is sawdust compressed into pellets for fuel for woodstoves - 27 cups or 8 lbs.

Guinea pig food – pellets – 9 cups or 3 lbs.

One-Step – a hydrogen peroxide based agent used to sanitize home brewing equipment – 3 tablespoons

Tablespoon

1 cup measuring cup

Water – 3 gallons

Plastic mister spray bottle – should be dedicated to your project and not used for anything that could harm your mushrooms. Available at hardware stores and garden centers for 2 or 3 diollars.

Cotton balls, or polyester stuffing – This is just for letting air in through a hole in the lid and keeping dust out. Polyester stuffing is available in fabric stores and also in aquarium stores as filter material.

Oyster mushroom spawn – I used Elm oyster, Hypsizygus ulmarius. As I mentioned above, I got mine at from a conference presenter. It should be available through Smugtown Mushrooms in Rochester, New York. I have used Smugtown often for other cultures and have been pleased with their products and service. Call to check current availability. It is also available from other web sources. I would suggest getting a grow kit which would likely be a bag of Elm oyster mycelium on sawdust or straw. I think one grow kit should be sufficient for at least one bucket. The bag I used was quite small – maybe 3 inches in diameter and about a foot long. Most grow kits would be quite a bit larger than that, so they might work for two buckets.

Step 2: Make Your Culture Bucket

A number of you tube videos show ways of growing oyster mushrooms using 5 gallon buckets. This is one I happened to see. If you watch it you will note that materials and methods are quite different in this instructable but except for the size of the holes, the two bucket setup is similar. I drilled sixteen holes in the side of a bucket, spaced fairly evenly, with a ½” spade bit. I drilled one hole in the center of the bottom of the bucket and four other holes around it. I drilled one hole in the center of the bucket’s cover. This is the bucket that will contain you mushroom culture. It will be placed in a second bucket during the first phase of your mushrooms’ growth, the time when the mycelium is spreading throughout your culture media. This second bucket doesn’t need any holes.

Step 3: Sanitize and Hydrate the Pellets

Wipe your large plastic tub down with a paper towel moistened with rubbing alcohol. It’s best to wear disposable gloves for this to avoid drying out your hands. Put the pellets in your tub. The reason for the tub is to make mixing the ingredients easy. Add One-Step to the water at a one tablespoon per gallon rate, so 3 tablespoons for your 3 gallons, and mix well. Add this to the pellets in the tub. Mix well and let it set until the pellets have absorbed all or nearly all of the solution. The pellets expand about three times in volume when hydrated. Then add the guinea pig food and mix again. Then open the grow kit, take out the contents and break it up into bits. It’s best to wear disposable gloves for this step to protect the culture. Mix well again. Now put it into the bucket with the holes. (It should be about the right amount to fill it up one bucket. If you have extra, put it in a plastic bag, cut some small slits in the side and bottom of the bag, and hang it up.) Put the cover with the hole in the center on the bucket on your full bucket and plug the hole with cotton balls or polyester stuffing. Put this bucket in the second bucket, and set it aside to grow mycelium. Pull it out every week or two just to quickly check if the mycelium is spreading most or the holes and if any pinhead mushrooms, primordia, have popped up.

Step 4: When Primordia Appear, Move Your Bucket to a Humidity Tent and Mist It Daily

Humidity tents can be constructed in many ways. Set yours up in a location that gets some light. I set the bucket in a pan of water on an upside down flowerpot so that the bucket was above the waterline. The bucket then benefits from the humidity of evaporating water without sitting in water. I happened to have a crab pot net which I turned upside down and suspended, draping a transparent plastic bag over it. The same could be done with a clothes hanger stretched into a circle. I put this humidity tent over the bucket. I slit a hole in the bag so I could mist the bucket and the inside of the bag through the hole. Mist the bucket at least once or twice a day. If is seems your primordia are drying out, you can increase your misting and, if necessary, let some water trickle through you bucket via the cotton or polyester stuffing plugged hole in the top. I sometimes set mine outside on my deck in the rain. When the mushrooms start to enlarge they grow quickly.

Step 5: Harvest and Enjoy!

Harvest your elm oysters before they get super huge, as they will get tougher. Enjoy your first batch in moderation as is a good idea with any new food. Then pig out if you like! I would suggest that your first batch deserves to be lightly fried by itself in a little butter or oil of your choice, and seasoned with a little salt and pepper.

To see another way I grow oyster mushroom, and to see some background on mushroom culture and links to other mushroom instructables, visit oyster mushrooms simplified.