Oyster Mushrooms in Plastic Bags

Well, my earlier oyster mushrooms grows in jars and plastic bottles worked, but didn't produce large yields. So I figured out what could be the reason and came up with a few ideas:

1.  I used clones from store bought mushrooms and these mushrooms came from a package of mixed mushrooms. From a mix of oyster mushrooms, golden oysters, shiitake and white button mushrooms. In order for the custommers to see all mushrooms in the mix the oyster mushrooms had to be quite small. First I assumed that they just used the smaller mushrooms of their oyster clusters, but I guess I was wrong and that they use a special culture producing only small mushrooms. So I bought a new package containing only large oyster mushrooms and cloned these.
2. Jars and bottles aren't good fruiting containers. The substrate on the bottom of jars and bottles doesn't receive enough air and therefore the oyster clusters remain small. Therefore I decided to use plastic bags and cut a few x-shaped insertions on all sides of the bags.
3. I used colonized coffee grounds as spawn while other people often use grain spawn. Grains are more nutrient dense than coffee grounds and therefore could produce larger yields. The problems of grains is that they don't fit into my philosophy of using waste products for oyster mushroom cultivation and growing them in the most simple and cheap way possible. So I skipped the idea of using grains and tried the new clones in plastic bags inoculated with colonized coffee grounds. And as you can see in the pictures below grains aren't necessary for higher yields.  

Day 3: The bag contains 3 Liters (3/4 gallon) of pasteurized wheat straw as fruiting substrate.

Day 4:

Day 5:

I harvested them at this stage. The yield was nearly 300 grams. I guess that's acceptable for 3 liters of wheat straw. The bag may even produce a second flush.

Oyster Mushroom Cultivation In Plastic Bottles

This time I tried something new. I had a large soda bottle (3 liter) and decided to use it for growing oyster mushrooms. Because of it's rather small opening it's difficult to fill the bottle with wheat straw. So I choose a mixture of coffee grounds and small pieces of wood. About 1 part coffee grounds to 3 parts wood.

I chopped up the wood myself, what was quite some work. In future I will try out some barbeque wood chips. Barbeque wood chips should be made of food quality wood and should not contain any harmful additives. Wood fuel pellets are another alternative but some companies  put additives in the pellets to make them burn cleaner. Before using them I must be sure they contain nothing else but sawdust. 

Hydrating small pieces of hardwood isn't as easy as when using wheat straw. It takes a couple of days before they are fully hydrated. I filled the wood pieces into jars, filled the jars with boiling water and put their lids on immediately afterwards.

Cooling off creates a subpressure in the jars and you hear a loud "click-like" sound when the lids are pulled inwards. It's best to pepare the jars 1-2 weeks before usage. This way one can be sure the wood is fully hydrated. Originally the jars were filled to the rim with boiling water. The empty space on top is a result from the air in the wood that was replaced by water. 

Preparing the jars 1-2 weeks before usage also serves another purpose than just completely hydrating the wood. If the wood wasn't fullt sterilized by the boiling water, contaminants will grow and will produce gases. This gases will produce an overpressure in the jars and will bend the lids outwards. As long as there is subpressure in the jars the wood should be sterile. If not pour off the water, rinse the wood under clean tap water, fill it back into the jar(s) and fill the jar(s) with boiling water again. This should kill all contaminants. To be sure leave the jar(s) for another week.

After filling the bottle with wood and coffee ground it took about 6 weeks until primordia formation. Unfortunately the the lower part of the bottle wasn't fully colonized at this point. 

Originally I intended to make a few holes in the bottle so that a few oyster mushrooms clusters would grow at the same time. The first primordia appeared at the surface, at the opening of the bottle. So I decided to just go for this cluster. Hopefully the bottle will fully colonize after my first harvest and I can proceed with my original plan.

First pins. For better fruiting I layed the bottle on it's side.

Four days later. I harvested them at this time.

Overal conclusion: Empty soda bottles are suitable for oyster mushroom cultivation and provide free growing containers for heavy soda consumers. One could prepare a number of bottles at the same time and use a wine rack to place them behind a window. For a more evenly colonization it may be better to let the bottles colonize in two steps. First the lower halfs and, after their colonization, the remainig upper halfs of the bottles.

Low Tech Oyster Mushroom Cultivation in Jars

This is a very low tech method for growing oyster mushrooms indoor. Ideal for small scale growers and absolute beginners.

What we need (per jar):

1 canning jar (1500ml)
250ml oyster spawn
1 small bottle (100ml) or something similar shaped
Straw (any straw-wheat, barley, rice etc.)

1st step: Fill the jar with straw and put the small bottle (I used an empty bottle of rubbing alcohol) in middle of the straw. Keep the lid on the bottle to prevent it from running full of water in a later step.

The straw stalks should be about 2-5 inch long. Squeeze the straw in really hard. You want to get as much straw into the jar as possible. Don't worry, even when squeezed hard, with straw this size there will still be enough air in the substrate. There shouldn't be any air pockets in the substrate. Now and then I also added a table spoon of dried coffee between the straw. Fill the jar with straw to about 1 1/2 inch below the rim.

Now select a small amount of small straw particles and fill them into a small canning jar. I use these to get an even/flat surface on the substrate.

2nd step: Pour boiling water in both jars, filling them to the rim. Put the lids on both jars and let them cool off to room temperature. Depending on room temperature this can take up to two hours or longer. The temperature should'nt exceed 77F/25C. Higher temperatures can harm the spawn later on. Don't use lids with a build-in air filter at this stage.

Large jar:

Small jar:

3rd step: Once the jars have cooled down to room temperature pour off the water, close them with their lids again and put them upside down on your working table. This allows the water to completely drip off.

4th step: Once the water has dripped off open the lid (while still holding the jar upside down) and let the water above the lid run off. Now put the jar upright again and pull the small bottle out of the substrate.

5th step: Now fill the hole with your oyster spawn. In this example I used home made oyster spwan on coffee grounds. Also cover the whole surface of the substrate with a thin layer of spawn. Don't squeeze the spawn too hard into the hole. Just sprinkle it in with a spoon.

Now cover the surface with the small straw particles to about 1/2 inch below the rim. 

Close the jar with a lid with a build-in air filter (coffee filter, polyfill, tyvek or whatever filter material you have at your disposal) and put it in a safe place without direct sunlight or too much air flow.

After about a week you will see the first mycelium strains appear.

3-4 weeks later the jar should be fully colonized.

Once the substrate is completely white it's time to open the lid once a day to catch the moment the first primordia appear. When you notice the first primordial grow set the jar on your windowsill and spray it's surface lightly with water. It should be moist, but not soaking wet. Just enough to prevent it from drying out.

In most cases the first primordia will abort. Probably because, without the lid, the substrate receives more air and gets a new growing impulse. But don't worry, this isn't a problem. Just keep spraying the surface and wait for the next primordia. This can take 7-10 days.

Day 41: The first surviving primordia have appeared and reached a stage at which they will no longer abort.

Day 43: The mushrooms got a lot larger by now.

Day 45: The mushrooms reached their final stage. At least i harvested them at this point. The weight was about 50 grams. Not that much, but of course you aren't restricted to make only 1 jar.

From the other side:

2nd flush: The first flush seems to have used up most of the jars nutrients. It took a couple of weeks for the next flush to appear and it produced only two mushrooms.

 

Although the yields aren't that great with this method jars like this fit on every windowsill and are ideal for small scale growers. It's also ideal for beginners to fully understand the growing proces of oyster mushrooms so, if they wish, they can use larger containers for future grows.