Growing Oyster Mushrooms

Learn how to grow oyster mushrooms in a simple laundry basket using little more than straw and water.

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Growing edible mushrooms can be easy, but you must pay attention to the requirements of the species you are growing. Each species has specific “ideal” requirements for temperature, humidity, light, and nutrition. Generally, oyster mushrooms are the easiest to get started with, and you can start with a kit or buy some spawn online to grow them in straw.

Grey Oyster mushrooms (Pleurotus ostreatus) are very forgiving, but they grow faster and produce better with the following conditions:

Spawn Run: 75F, 85-95% Humidity, 12-21 Days, no light
Primordia: 50F-60F, 95-100% Humidity, 3-5 days, Fresh air 3 times daily, Partial Shade
Fruiting: 60F-70F, 85-95% Humidity, 4-7 days, Fresh air 3 times daily, Partial Shade

Pink Oysters (Pleurotus djamor) are better for warmer weather:

Spawn Run: 75F-85F, 90%-100% humidity, 7-10 days
Primordia: 65F-75F, 95%-100% humidity, fresh air 3 times a day, full light, 2-4 days
Fruiting: 70F-85F, 85%-95% humidity, fresh air 3 times a day, full light, 3-5 days

Materials & Tools

Materials

Oyster Mushroom Spawn

Laundry Basket

Medium Trash Bag

Chopped Straw

Agricultural Lime

Agricultural Gypsum

Cardboard

Tools

Large Pot

Old ice chest

Screen

Thermometer

Step 1: Pasteurize straw

Get a large pot and fill with 2 gallons of hot water
Put the pot on the stove, and heat until the water reaches 180 degrees F
While the water is heating, prepare the straw by filling the laundry basket with straw. You want to fill the basket a little at a time, and compress the straw as you go.
Dump the straw into an old ice chest.
Dust the straw with a bit of lime (1/4 cup) and gypsum (1/8 cup)
Mix the lime and gypsum in.
Once the water is up to temp, dump the water over the straw.
Close the ice chest and let the straw soak for 1.5 hours.

Step 2: Load the basket

After the straw has soaked for at least 1.5 hours, set up a screen so that you can place a think layer of straw to cool.
Lay out a layer of the hot straw on the screen. The layer should be less than 2 inches thick.
Once the straw has cooled to the touch, load a layer into the laundry basket and compress. The layer should be about 2 inches thick.
Place another layer of straw on the screen.
Cover the layer of straw in the basket with spawn. Make sure the spawn stays at least 2 inches away from the edge of the basket. You want the spawn to be evenly distributed on the straw.
Repeat steps 3-5 until the laundry basket is full.
Once full, run your hands around the edges of the basket, making all the loose straw fall.
Cover the basket with the trash bag.

Step 3: Spawn run

Place the laundry basket in a warm, dark room. The room should not exceed 80F, and be at least 70F.
Check on the basket after one week. You should start to see white mycelium growing at some of the holes. Cover, and check again in another week.
Once the mycelium has completely covered the straw, you are ready to start pinning (primordia formation).

Step 4: Primordia

Uncover the basket and place in a cool, well lit room. You want the room to be 50F-60F, and have high humidity. If humidity is a problem, place a loose plastic over the basket.
Expose the basket to fresh air 3 times a day. Mist the basket once a day.
Time varies on primordia formation, but it can take as much as a week.
When primodia form, they will look like tiny little pins. Once the basket is full of these, it is time for the fruiting stage.

Step 5: Fruiting

Move the basket to a slightly warmer room with more light. The humidity can be a bit lower here, but a loose plastic draped over the basket works well.
Expose the basket to fresh air 3 times a day. Mist the basket once a day.
Watch out for fruit flies, they can destroy your harvest. If flies are detected, move the basket to a better location and make the plastic covering a bit tighter.
Pick the fruit when the heads just begin to turn upright. Be careful, fruit can develop extremely fast, one day they look like pins, and the next day they are ready to harvest.
Once you harvest the fruits, mist the basket well, and go through the primodia procedure again. The basket should be able to fruit 2-3 times.

Step 6: Cloning

Once you harvest your mushrooms, you can make more spawn through cloning on cardboard. Cut all the stems and bases of the harvested fruit into tiny pieces.
Cut cardboard into 6″ by 6″ squares. You’ll want a stack of cardboard at least 8″ high.
soak the cardboard in water for about 15 minutes, or until the layers of cardboard separate easily
Prepare a trash bag by opening it, and setting it flat on the counter. You will set the cardboard in this bag.
Separate a piece of cardboard by pulling the layers apart. You should have one piece with corrugations, and the other piece will be flat.
Place the corrugated piece in the bag. Put several small pieces of mushroom, spaced about 2″ apart, on the cardboard layer. Cover with the other side of cardboard.
Repeat steps 5 and 6 for all of your cardboard, setting each piece on top of the previous layer.
Close the bag with a loose knot. Mark the date and species of mushroom on the bag, and set in a warm, dark room (spawning Room) for 2 weeks. Check the bag every few days for signs of growth. The mycelium will be white and fuzzy, and will grow out from the mushrooms pieces and cover the entire stack of cardboard.
When the mycelium has covered the entire stack, it is ready to go into a laundry basket. To use this as spawn, pull out a layer of cardboard, tear into small pieces, and layer on the straw.
If the cardboard starts to stink or has green mold, dispose of it. You want clean spawn going into your laundry baskets.

Nothing is more rewarding than eating your own homegrown mushrooms. Growing oyster mushrooms is easy, and it’s a great project to do with kids. They’ll enjoy watching the quick growth of the fruiting bodies as well as the rewards of eating them after harvest.