By Andrew Campbell
I always find mushrooms to be that incredibly accessible food that goes with a lot of things. Homemade pizza, it needs mushrooms, of course. Fried mushrooms are a great topping for a burger or steak! And of course a fresh salad needs a few mushrooms cut up in it too. But what’s the process for growing those mushrooms?
Fortunately, Canada is a large producer of mushrooms, with farms like the Good family farm growing and selling mushrooms year round. Murray & Chantelle Good grow mushrooms on their Putnam, Ontario farm, sell a few from their farm store, and a lot to stores like Costco. After all, this family is growing 40 thousand pounds of mushrooms a week!
In this video, they’ll take us around their growing rooms to show us what a mushroom grows in, how they are picked and packed, and reveal the surprising truth about three brown mushrooms varieties – that they are all really the same!
How are mushrooms grown? And how long is the growing cycle?
The growing cycle for mushrooms is six weeks. The first three weeks are spent growing the vegetative part of the fungus, called the mycelium which is kind of like the roots. This is also called colonizing the casing layer. The last three weeks are spent picking mushrooms and letting them grow to pick again.
After the first three weeks have passed, the temperature in the growing room is dropped below 20 degrees Celsius. This temperature change signals the spawn to develop a fruit body (mushroom) and to drop the spores that are in the gills underneath that mushroom cap. This is the reproductive mechanism for another mushroom to grow, and is basically tricking the mushroom into growing fruit bodies so that they can be produced year round.
Mushrooms are harvested in stages or flushes. The first flush is harvested over four or five days. They are then left to rest for three days, where the mushrooms grow right back up. This is the second flush and will be picked over four days, followed by another rest of four days. Then mushrooms grow right back up again for the third flush of getting picked.
The first flush represents roughly about 60% of the total yield. The second flush is roughly 30% of the total yield. And the third flush is 10%.
What do mushrooms grow in?
Mushrooms grow in 22 centimeters (8 inches) of pasteurized substrate. This is usually a straw layer that has been partially composted and pasteurized to purify it, with a peat moss layer on top.
What types of mushrooms are grown in Canada?
The most popular mushroom in Canada is the White Button followed by brown Crimini and Portabellas. There is a lot of growth in the demand for specialty mushrooms, like Shiitake, Oyster, King Oyster, and Enoki. These specialty mushrooms are typically grown differently in things like bottles, on wood logs or containers filled with sawdust.
What is the difference between white, cremini and portabella mushrooms?
Typically grocery stores offer white mushrooms in three sizes – button, medium and large. The same is true for brown in three sizes – crimini, portebellini and portabella. In both cases, they are the same variety (either brown or white) and differ only in size. Brown mushrooms are usually sold when they are 5 centimeters (2 inches) in diameter. If left to grow larger they are called portabellini when they reach 7 centimeters (3 inches) in diameter. Finally if left to grow into large mushrooms they are called portabella.
How fast does a brown mushroom grow?
Mushrooms have a fast growth rate, doubling in size in 24 hours. That’s growing 4% an hour! Once they are seen in the soil substrate, they can be picked in four days, or left to grow into the larger portabellas.
If a cremini and a portabella are the same type of mushroom, why do they taste different?
If you look at a cremini mushroom, the gills underneath the cap haven’t expressed themselves. When the mushroom gets bigger, like a large portabella, they will open up and you’ll actually see the gills around the bottom. That is where all the flavour is. The gills give all the flavour.
What does the inside of a growing room look like?
Mushrooms can be grown year round. The growing room has a central aisle with six or seven tiers filled with a casing layer that grows the mushrooms. In the video, the rooms are 558 square meters and will grow about 40,000 pounds of mushrooms in the six week cycle.
How are mushrooms harvested?
Mushrooms are harvested by hand. The harvester will have a trolley equipped with a built in knife and weigh scale. The mushroom is picked by grabbing hold of the mushroom and twisting upwards. The stem is trimmed with the knife on the trolley and put into a basket on a scale. Each basket is full when the scale weighs in at 5 pounds (2 kg). The harvester takes the basket off when it is full, stacks it behind them and put another basket on the trolley to continue harvesting.
What is the ideal environment for growing mushrooms?
There is a myth that the lights have to be off in order to grow mushrooms. It’s not true. Lights on or off, it’s all about evaporation and a warm humid environment. Mushrooms need an evaporative environment to grow.
What’s new in mushroom growing?
Mushroom farmers in Canada have made substantial investments in new technology to increase productivity, improve quality and food safety. Most mushroom farms have re-modeled or built new packing and storage rooms, with refrigeration, vacuum-coolers, etc., completely separate from the growing rooms. Mushroom growers continue to invest in not only food-safety training and documentation, but also the health and safety of the workers.
Why do you need to wear hairnets and lab coats to visit a mushroom farm?
The answer is basically for food safety and food security. It is also important to prevent the transfer of disease around the farm that could impact the quality. In the video below, there are 6 different rooms that each have a six week growing cycle, so each week, one room is beginning its cycle while another is ending. At the end of the six week growing cycle, they could be growing other molds that affect the mushroom growth that shouldn’t be transferred to the new rooms.
What are the dark flecks on the mushrooms I purchase at the grocery store?
It’s just the peat moss, the pasteurized substrate that mushrooms grow in.
Just brush them off or take a damp cloth and just wipe them off. Don’t peel the mushrooms because they have a natural layer around them that helps keep them fresh.
Once harvested, how do you store a mushroom so it will keep well?
Once harvested, mushrooms are conveyed to a spiral belt. The spiral belt uses cooling technology to take the mushrooms from 18 degrees celsius to 1 degree celsius at the core of the mushroom, not just the outside of the mushroom. It takes 50 minutes for mushrooms to cool down to 1 degree celsius on that spiral belt. Mushrooms are stored at 1 degree celsius all the time. Farmers must maintain the cold chain. If you warm up something that is cold it condenses moisture and that’s where you get oxidation (brown spots) which is that start of the decomposition process.
Once purchased at the grocery market, store mushrooms at 1 degree celsius in a paper bag. If you don’t have anywhere that is 1 degree, storing in a fridge at 4 or 5 degrees celsius is fine.
For more information on Mushrooms check out – mushrooms.ca.
Full Mushroom Video From FreshAirFarmer Andrew Campbell’s Dinner Starts Here Series