Are you considering growing oyster mushrooms? Maybe you want to make some extra cash or grow food even when the weather outside isn’t cooperating. Or perhaps you want to dip your toe into the world of mushroom cultivation.
Whatever your reason, you’ve come to the right place. Oyster mushrooms are ideal for beginners because they are relatively easy, quick and low-maintenance to grow. Oh yeah – and they’re delicious.
Way back in the day in 1993, I purchased my first farm. To support my own farming endeavors, I took a job managing a gourmet mushroom farm where I began a passionate affair with oyster mushrooms. They just naturally appeal to the senses with a variety of colors and shapes.
There’s something so incredibly satisfying about twisting off a fresh mushroom that you’ve grown yourself. Not to mention the money you can save on your food bill in the process.
Oyster mushrooms are somewhat labor intensive to get started because you need to prepare the growing material. But once you get them going, they’re easier to raise than other popular mushrooms shiitakes or lion’s mane.
This guide will focus on growing oyster mushrooms using substrates of straw or sawdust. This method ensures a more controlled environment which means greater production and a better return on your investment. Ready to get started?
There are several types of oysters mushrooms, each with its own color and flavor profile.
Blue Oysters (Pleurotus ostreatus var. columbinus)
Sometimes referred to as blue pearl oysters, these mushrooms are popular because they grow rapidly. They also tolerate cooler weather, growing in temperatures from 45 to 65°F, though it must be at least 60°F for fruiting to take place.
Blue oyster mushrooms appreciate good air circulation and do better outside, but you can grow them indoors, too.
Golden or Yellow Oyster (Pleurotus citrinopileatus)
This mushroom is a delightfully rich yellow color. It has a stronger flavor than some other types. In the wild in Japan and northern China, it grows rampantly on decaying wood.
They grow well in bags with substrates of sawdust and straw. Yellow oysters have a high conversion rate which means that they make good use of nutrients and are prolific.
Pink Oyster (Pleurotus djamor)
This is my favorite oyster mushroom! They have a pretty pink hue and they’re popular with chefs for their mild, woody flavor. They’re vigorous growers – we got the highest weights per bag with this type when I was working at the mushroom farm. They grow quickly and fruit at 21 to 28 days.
Pink oysters like temperatures above 60°F, so they do well in a greenhouse (or a bathroom). You can grow them on straw or sawdust. In straw, they tend to produce lots of small mushrooms. In sawdust, they grow fewer but larger mushrooms.
King Oyster Mushroom (Pleurotus eryngii)
This variety grows with a round cap and sizeable stem, and they can get quite large – up to a pound in weight. They grow a bit slower than other varieties and do best in sawdust. They benefit from a casing layer. King oysters can be susceptible to blotch.
This variety is markedly mild when cooked, so it’s perfect when you want something with a meaty texture that will take on flavoring.
Phoenix Oyster (Pleurotus pulmonarius)
Also known as the Indian oyster mushroom, this brown type is a cinch to grow and can mature in under a week. It does well in straw, and fruits in warmer conditions than other varieties, making it ideal as a summer mushroom. They’re firm and fleshy with a slight anise flavor.
Before we get started, there are a few terms you should know.
- Spawn – The spawn is essentially mushroom seed. It’s the living fungal culture that you’ll attach to a growing medium.
- Substrate – A medium or substrate is the stuff that you put the mushroom spawn in that feeds the mushrooms as they grow.
- Inoculation – The process of adding spawn to a substrate is called inoculation.
- Mycelium – The mycelium are thread-like spawn filaments that will join together to form a colony.
How to Plant Oyster Mushrooms
When growing oyster mushrooms, you can choose from several different mediums. The most popular and reliable substrates are straw and sawdust, though some people use cardboard or cotton waste. You can also purchase pre-made substrates.
- Chop or cut clean straw into 1 to 3-inch pieces. You can use a wood chipper for this.
- Add the straw to a large tub of warm water with a small amount of dish soap. Swish it around. Pour the soapy water out.
- Rinse with clean water by running the garden hose over the straw.
- Pasteurize by cooking straw in a large pot until it reaches 150°F.
- Drain and place it on a clean, sterilized table.
This may seem like a lot of work – and it is – but studies show that a sterile environment maximizes production. If you plan to do multiple bags, it can help to set up an assembly line system. Professional mushroom growers often invest in an autoclave to speed up the process.
On the other hand, if you want to experiment with just one or two bags, you can microwave the straw to sterilize it.
Only make as much as you plan to use right away.
Using Sawdust or Wood Pellets
Sawdust is an equally good medium for growing oyster mushrooms. The sawdust needs to be from hardwoods such as oak or hickory. You can call your local sawmill and see if you can work out a deal.
Sawdust must be sterilized at a higher temperature than the straw because it can contain mold spores which interfere with growth.
- Bring sawdust to a boil and cook for an hour.
- Alternately, you can soak sawdust in a high-pH lime bath for 18 hours.
- Cool (if necessary).
- Drain through a metal colander.
You can also microwave small batches of sawdust.
Hardwood pellets marketed for wood smokers work well, especially since you don’t have to sterilize them. Soak the hardwood pellets in warm water to break them down, and they’re ready to go.
Where to Get Spawn
Purchase spawn online from your favorite mushroom provider. You can get grain spawn in different sizes and suitable for sawdust or straw substrates.
Grain spawn is generally shipped on rye grain and is actively growing mycelium. This is different from plugs which are used to inoculate logs when growing types like shiitake mushrooms.
Let your substrate cool and check to make sure it has the right moisture level. You want it to bind together if you squeeze it in your hand, and some water should slowly drip out. If a lot of water comes out, it’s too wet. If no water comes out and it doesn’t bind, your substrate is too dry.
Now it’s time add the mushroom spawn. Use about three pounds of spawn per twenty-pounds of the substrate. Mix it in thoroughly, breaking up the clumps.
After everything is mixed well, place it in your bags. You can purchase bags from mushroom supply companies or use the larger 2-gallon plastic bags from any big box store.
The mushroom bags often have holes already in them. If you buy regular plastic bags, you’ll need to poke holes in the bags every 2-inches along the sides and bottom.
Once you are done with inoculation, you can breathe a big sigh of relief. The hard part is over.
Caring For Your Oyster Mushrooms
Mushrooms need to incubate so that they can grow. Place your bag in a warm, dark area at about 65-75°F.
Dark can mean a large closet, garage or shed. Growing oyster mushrooms in a greenhouse is also possible with a shade cloth covering. I recommend shade cloth that is at least 50% shaded.
Mushrooms need good air circulation, so set up a fan or two if necessary. The fan should not be blowing right on the bag but moving the air throughout the space. If your greenhouse has large fans, place the bags at least 10-feet away.
Mushrooms don’t like to be bothered, so place them in a corner or another out of the way location.
After 3 to 4 weeks, depending on the variety, the mycelium will have established a good colony. You’ll be able to tell because the stuff inside the bag will turn white.
At this point, your colony will start to fruit. The pins (fruit buds) will begin to come out of the holes in your bag.
You can entice your mushrooms to produce fruit by misting the bag with warm water. Also, now is the time to let your bags have indirect light. A north facing window works well.
You can cut a slit into the bag to improve air circulation, which replicates the conditions a mushroom would experience as it grows out of a log in the wild.
It takes about 5 or 6 days for them to reach harvest size, so keep an eye on the mushrooms during this stage. Once you pluck a mushroom, the pins will be very small and continue to grow outside of the bag. They will continually produce fruit over several months before the mycelium exhausts its energy.
What To Do After Your Bag is Spent
One way to continue growing oyster mushrooms after the bags are spent is to add it to your compost pile when you are done. Mycelium is nourished and warmed by the composting process.
They’ll continue to grow in the pile and can begin fruiting again. When you have mushrooms outside like this, it’s essential to monitor them. A sunny day might make them grow too quickly and split, or dry out. Rain can cause them to get soggy and degrade.
The spent mushroom bag – minus the plastic, of course – is also a nutritious additive for a vermicomposting bin.
Oyster Mushroom Kits
You can purchase oyster mushroom kits if you want to take some of the work out of the process. The big advantage of kits is that they are simple to use. They come sterilized with pre-inoculated and colonizing mushrooms.
The downside is that they can be expensive, especially the quality kits, and there are fewer variety options. Sometimes the cheaper kits aren’t worth it because they don’t produce well. Read reviews and buy from a reputable company.
- Drying out – if your substrate or mushrooms start to dry out, spray them with water.
- Small heads – Long stems and small heads are caused by too much CO2. Open a window or door several times a day to increase air exchange.
The biggest challenge to growing oyster mushrooms in bags is avoiding mold. After all, you have created a warm, moist environment, something both fungi and molds seek.
Molds are everywhere in our world. They may take hold because you didn’t kill them off during the cleaning and sterilization phase, or they could be introduced to your environment through daily activity.
If you have a small patch of mold, you can simply cut it out and remove it. If your whole bag turns green, it is time to send it to the compost pile.
Blotch is a bacterial disease that causes lesions to form on the cap and stem of mushrooms. Chlorinate your water and allow mushrooms to dry between spraying if you struggle with blotch.
Insects can damage growing oyster mushrooms, though this is less common than mold. Cecidomyiidae is a small fly called gall gnats that eat the underside of the mushroom.
Keeping your growing area clean is the best prevention. You can use sticky traps to control flying insects. Mushrooms are sensitive to pesticides so don’t spray them with anything.
Black Scavenger Flies
Scatopsidae is known as the black scavenger fly. It feeds on decaying plants and dung. Control them in the same way as gall gnats.
Harvesting and storing
Harvest your mushrooms before they begin dropping their spores. You can tell that’s about to happen when the outside edges of the head start to curl up. Another indication that they’re ready for harvest is when the heads begin to flatten out and stop growing.
To harvest, twist the mushroom off or cut it off with a knife.
In general, mushrooms don’t have a long shelf life. Oyster mushrooms, due to their thicker walls, fare a little bit better.
Store in a paper bag in the refrigerator. Oyster mushrooms tend to come in groups. If you get too many at once preserve them by drying.
Oyster mushrooms are high in protein – 30% by dry weight. They’re also low in cholesterol, and they contain molecule lovastatin which helps to lower cholesterol levels. They’re a popular food with people on vegetarian and vegan diets because they’re thick and meaty so they can be substituted for meat in soups and stews.
Oyster mushrooms are best cooked. Eating many of them fresh can cause you to feel sick. They contain a protein called ostreolysin which can be toxic if eaten raw in large quantities. To avoid, cook them to 140°F.
You’ve done the work, now it’s time to enjoy! Let us know how it goes, and be sure to share your favorite recipes in the comments.