How to Grow Oyster Mushrooms (Low Tech)

Intro: How to Grow Oyster Mushrooms (Low Tech)

We have been introducing mushroom cultivation as a nutritional supplement and cash crop for the landless poor. Oyster mushrooms are a high yield, fast growing crop. They are known to help lower cholesterol levels and are a great source of potassium, iron and protein.

This instructable gives a low tech, step by step guide to growing both pleurotus ostreatus (winter strain) and pleurotus pulmonarius (summer strain). Oyster mushrooms are highly tolerant of variations in temperature, humidity, light levels and carbon dioxide levels, making it a great choice for first time growers.

See related instructable - How to Grow Oyster Mushroom Spawn (Low Tech)

STEP 1: Materials

You will need...

Straw (the medium for growing the mushrooms in)
Containers (for soaking straw)
Plastic bags (or reusable containers for holding straw)
Elastic bands or string (to constrict bag opening)
Cotton wool (to filter out contaminants)
Barrel or drum (for pasteurising the straw)
Material liner (for holding bags within barrel)
Gas burner (for heating barrel)
Bleach spray (to clean growing room)
Spoon, gloves, clean clothes, face mask (to look the part when inoculating straw)
A growing area that can retain moisture in the air, shaded with some light
Possibly plastic sheeting (to help retain humidity & to reduce other unwanted moulds)
Mushroom spawn (see How to Grow Mushroom Spawn)
A water or weed sprayer (to increase humidity within growing room)
A thermometer and hygrometer (to keep an eye on temperature and relative humidity)

STEP 2: Soak Straw, Drain and Bag

The mushrooms require a medium to grow in, in this case we will be using straw. The straw length should be approximately 5-10 cm (2-4 inches). Placing the straw in water tight containers, submerge the straw in water for 24 hours. Wash, rinse and drain thoroughly, then bag in 5 litre plastic bags ready for pasteurising.

STEP 3: Pasteurise

Position your drum onto the heat source (we used a gas burner), pouring around 40 litres of water into the drum. Place a suitable platform at the bottom of the drum, one that will keep the bags above the water yet allow steam to rise. Insert a material bin liner and fill with the prepared bags of straw. Close off the bags with the liner and cover the drum with a lid. Heat the drum, steaming the bags for approximately 60 minutes. It should take around 30 minutes for the steam to make its way to the top bags (the temperature should near 95°C ~200°F). Leave to cool, removing the bags and transferring them to the growing area.

STEP 4: Prepare Growing Room

The growing room should be clean and dimly lit (shaded with indirect sunlight), able to retain moisture in the air yet also provide an airflow when ventilation is needed. Plastic sheeting can be used to seal off an area to help retain humidity and to reduce other unwanted moulds and insects.

To prepare the room for the inoculations, spray a 1:20 (5%) solution of bleach along walls and corners (any area where mould might like to grow).

Temperatures of 10°C to 24°C (50°F to 75°F) for pleurotus ostreatus (winter) and 10°C to 30°C (50°F to 85°F) for pleurotus pulmonarius (summer) should be available depending on stage of growth (initial spawn run, colonisation, pinning and fruiting).

STEP 5: Inoculate Bags

Before inoculating the bags of straw, make sure you have showered and are wearing clean clothes. Clean your hands with antibacterial soap or wear sterile gloves. A face mask and hair cap will also help reduce contamination (we are very dirty creatures).

Open the bags of straw and the mushroom spawn. Taking a sterile spoon, place a few spoonfuls into the straw, breaking it up and mixing lightly. As a general rule, the more spawn you add, the faster the substrate will be colonised (with 1 litre of spawn, we inoculated about 10 bags - you could inoculate more).

Restrict the opening of the bag by placing a rubber band (or cord) around the bag's neck. Taking a small piece of cotton wool, plug the bag's opening to reduce the chances of contamination and insect infestation. Leave to incubate.

STEP 6: Encourage Colonisation

Once inoculated, the bags should be left to incubate. During this time the spawn "runs" (mycelium spreads) throughout the straw. The spawn run will be complete when the mycelium has spread entirely throughout the bag (the straw is then fully colonised).

Depending on the mushroom variety, humidity and temperature, this process should take between 1 to 3 weeks.

Pleurotus ostreatus (winter), 24°C (75°F) 2 to 3 weeks
Pleurotus pulmonarius (summer), 24°C to 30°C (75 to 85°F) 1 to 2 weeks

During incubation, light is not required, however, make sure the bags have plenty of fresh air.

STEP 7: Monitor Bags

It is important to monitor the bags for any sign of unwanted moulds and pests. While the straw is still in the bags, you shouldn't have a problem with insects or mice. However, the best policy for fighting both contamination and infestation, is prevention. You may want to spray some surfaces to deter flies and other insects from setting up home, mesh any windows and keep doors closed.

Regularly check bags for any mould contamination and remove any infected bags from the growing area. Black mould found within the straw may indicate ineffective sterilisation. You may also notice sprouting straw and the appearance of unwanted mushrooms such as the ink cap (see pictures). Green moulds are common and can be caused by contaminated spawn (ineffective grain sterilisation), high moisture / low spawn levels and ineffective straw sterilisation. At this early stage, it is better to simply remove infected bags, as you want to prevent its spread. Up to a 10% loss due to contamination is generally regarded as acceptable.

Finally, as the bags become fully colonised, the initial stages of fruiting (or pinning) may be seen.

STEP 8: Encourage Pinning

Once pinning has started, it is time to remove the substrate from the bags. Pinning naturally occurs as humidity increases, low levels of light appear and temperature levels fall. Increase the growing room humidity by regularly spraying with a water sprayer (avoid spraying directly on the mushrooms). You can also wet the floor and leave open containers of water in the room (95-100% humidity is recommended). As our climate is very dry, we only managed 60% at best, dropping down to 40%, by spraying 5 litres of water 2 - 3 times a day (even at these humidity levels a good result can be achieved). To prevent excessive CO2 levels, allow the growing area to flush with clean air before spraying. If you can, regulate the temperature accordingly.

Pleurotus ostreatus (winter), 10-15°C (50-60°F)
Pleurotus pulmonarius (summer), 10-24°C to 30°C (50-75°F)

You may notice an initial drying out of early stage pinning, as you remove the plastic. As you maintain the humidity levels this will regenerate. Keep a close eye on flies and spray when needed. If any mould is found, either remove the infected straw or the entire mound from the growing area.

STEP 9: Harvesting

As the mushrooms begin fruiting, it is important to keep the humidity high (85-90% is recommended). As before, allow air to flush through the growing area prior to spraying (oyster mushrooms require a consistent source of fresh air). Temperatures can now be higher than for the initial pinning stage.

Pleurotus ostreatus (winter), 10°C to 20°C (~50°F to 70°F)
Pleurotus pulmonarius (summer), 16°C to 28°C (~60°F to 80°F)

Remember to constantly monitor for pests, such as flies and mice, as they can quickly ruin a crop. You should expect three or more crops, each taking around a week or so to mature. You may harvest the mushrooms at any size, however, once a mushroom has reached its full size, you will notice it will begin to dry, turning a yellowish colour (they taste great, even dry). When harvesting, remove the mushroom completely, by twisting firmly at its base. After harvesting a few crops, we found it helpful to stack the mounds of straw, which seemed to help increase the yield. If you find your mushrooms with long stalks and small caps, they may not be getting enough light, also high CO2 levels can also lead to small deformities (allow for more fresh air). After the straw ceases to produce mushrooms, it can be fed to livestock or composted.

Now, finally take your harvested mushrooms and create a delicious mushroom meal. Enjoy.

See related instructable - How to Grow Oyster Mushroom Spawn (Low Tech)

Comments

[Kunal Chouhan]

Firstly, i filled 4 bags after 2-3 weeks first mushroom is grow but other polythene bags are still no response what i do

[kongerlu]

Hello, thank you for the very informative post. I want to know if recently cut straw from rice fields can be used as substrate, how long should the straw be cured/dried?
Please clarify, thank you...

[rocketsurgery]

Pasteurising the straw will prepare it as a suitable substrate. You may want to do some experiments to see if it makes a difference to contamination rates or yields. All the best.

[rocketsurgery]

Yes, cut straw is a great substrate - the pasteurising stage should ready it for the task :) All the best!

[sharmis1]

This one i made in my college days..

[Mycolah]

long stems and small caps mean there is too much C02 in the environment, for culinary purposes its best to have a short stem and a big cap but they look cool either way. some people who have their set up really dialed in will have a lot of C02 in their environment/tent at first so it initiates a lot of pins and then will introduce the proper amount of 02 for the short stem and big cap but this is only usefull for an environment with all the bags undergoing its first flush cause doing that with older blocks wouldn't be good

[Alleycat340]

Hey one question I forgot to ask was can you use this method for decent size production for profit say maybe 100 square feet of grow space? I do intend to expand my grow room in the future for larger scale production. I am a farmer and I’ve grown and sold vegetables and I’ve decided to shift my focus towards mushroom farming given the rising business and need for locally grown oyster mushrooms along with the high value average of 10% to 12% retail and 4% to 6% wholesale along with the option to create value added products. Thank you so much for your time and instructive tutorial it’s been the best one I could find so far on how to actually grow them most guides only give you a general overview so this is most appreciated!!!

[Mycolah]

A 100 square foot is plenty! that would be equal to a medium size operation, if I were you I would set up a few tents in there and fruit mushrooms within the tents, instead of spraying you should use an ultra sonic humidifier and vent out your tents and also have shelving within the tents to take advantage of vertical space. Depending on the floor of the room you could just throw tarps on the wall, floor, ceiling and install shelves and fruit your blocks that way. It all depends on how much you can afford to put into the set up

[taede11]

Can i use woodchips instead of straw?

[Mycolah]

If you aren't going to use straw I suggest using hard wood oak fuel pellets! they're much easier to work with and are cost effective. I get mine at mushroom media, i wish I had a fancy coupon code for ya but I dont :(

[xandriarobertdelacruz]

CAN I BUY FROM YOU Mushroom spawn CAN YOU DELIVER FROM YOUR COUNTRY TO MY COUNTRY PHILIPPINES

[Alleycat340]

Hey on step 8 when the pinning starts it says remove substrate from bag so the mound from then on is growing out of a bag exposed to the air?? Is there anywhere that can give me ratio of straw to spawn? Also how much can I grow in 100 square feet room? How about specific strain nutrition needs such as temperature, humidity, ph levels Nitrogen levels etc.? And generally what can I expect my yield to be from per mound.? How about what kind of lighting I would need for 100 square feet grow room and how much light is necessary? Sorry to unload all these questions just have been unable to find answers. Thank you so much!!!

[sri.helpothers0829]

Whether it harm the mushroom colonisation if we sprinkle water to maintain humidity over the bags before first crop or not

[rocketsurgery]

As long as your water is without too many impurities, you can also place trays of water within the growing area.

[ajaramogikhalfani]

In case I buy spawn but I'm unable to use all of it at the same time, does the unused spawn get contaminated or I can also use it at a later time.

[rocketsurgery]

You should be able to keep your spawn refrigerated and covered without too many issues for months.

[DelunK]

Very interesting post. Beautiful described
each and every step of oyster mushrooms cultivation. This post is helpful for
many individuals. Thanks for sharing this information subject to us. I am a
businessman and I am running a mushroom farm. I suggest, before going for any
type of mushrooms farming, the first and prior thing is the organic and the
real products used in farming. I purchase a mushroom kit from www.agrinoon.com/agriculture.
They provide materials and supplements for mushroom farming which is real
organic and finished products.

[soumya4friend]

Nice post...

[JADE SAIDI]

Hi I'm a beginner my bags got attacked by rodents during incubation period, where openings got created on them, it took 2-3 weeks for some to get colonized while others failed to colonize so after I exposed them to growth conditions and watering 2 times a day, tell me will I get good results and how long will need to see fruiting happen.. Thanks from Uganda

[ssprasad2010]

I am a beginner. I am based out of Solan, Himachal Pradesh, India. I started trying to grow oyster california variety as the temparature here is around 15 to 20 deg Celcious. I am trying to grow on a bag of wheat straw. I bought the spawn from a very reliable place and pasteurized my straw as guided by cooking it at about 60 to 70 deg c for 1 hrs. After this I tried my straw till they were at room temp around 20 deg c. Then stacked it in a polythin bag alternating with straw and spawn upto 3 layers. I tried to tightly pack an remove the air from the bag before closing the mouth. I then pinned holes for air to go. I kept the bag in a shady area indoors with good air circulation. I found good Mycelium growth in about 15 days. I then made some bigger cuts in the bag for primordial growth. Today is fourth day after cutting bigger openings. I am spraying water 2 to 3 times but no pin heads can be seen yet. Please help.