AIRDRIE, Alta. – Having a feast of fungus sounds revolting.
But when that fungus comes in the form of mushrooms that are sauteed, broiled, stuffed or eaten raw, some people can’t get enough.
It’s that culinary delight that keeps Heritage Mushrooms producing four million pounds of white button mushrooms every year.
Located north of Airdrie, just north of Calgary, the busy 120-acre farm is Alberta’s largest white mushroom producer. Started in 1980 by John Rathje and two other partners, the company was eventually sold to the ConAgra group. As of April 29, it was taken over by Money’s Mushrooms.
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Growing mushrooms is something of an art and most of it takes place indoors.
“There are two misconceptions out there. Mushrooms don’t necessarily need to grow in the dark and they don’t grow in manure,” said marketing manager Jim Deines.
As marketing manager, Deines is not afraid to tap grocery shoppers on the shoulder and ask how they like their mushrooms. That one-on-one conversation provides the best kind of customer feedback and most consumers tell him “it depends on what I’m cooking.”
Heritage supplies Alberta and Saskatchewan markets but most of the product ends up in Calgary stores.
Begins with compost
The mushroom-growing process starts with compost made on the farm from chicken manure and straw. From the time the compost recipe is mixed till mushrooms are packaged takes 65 days.
The company buys 8,000 to 9,000 large square wheat straw bales per year and 500 to 600 square yards of chicken manure from local poultry producers, said assistant agriculture manager Stan Bittorf.
Wheat straw is preferred because it absorbs water better than barley straw and has less nitrogen.
The compost piles spend 15 days outside in long windrows and nine days inside a specially designed shed. All equipment and the mushroom-growing technology were imported from Holland.
Plenty of water is needed in an operation like this to moisten the compost piles, water the growing mushrooms and wash down the facilities. To reduce costs, water is reused as much as possible. Two tanks collect rainwater and snow melt. Additional water is hauled from Airdrie.
To start the growing process, the compost is pasteurized and inoculated with mushroom spores imported from Pennsylvania. After the bale of compost is inoculated, it goes through a mixer that pours the compost onto trays about four feet wide. The trays then go to a growing room.
The growing beds are 85 feet long and stacked five high. They get water from watering trees, which resemble tall intravenous poles with spray nozzles set at the height of each bed.
The growing trays hold a layer of compost that provides nutrition. On top of that are two inches of peat moss through which the mushrooms grow.
“Any dirt you see on a mushroom is just peat moss.There’s no compost or chicken manure on it,” said Bittorf.
Planting is done at the beginning and end of the week so fresh crops are ready for the start of the retail week followed by another batch for weekend shoppers.
If they want to make changes in the compost mix, temperature or water supply, experiments are conducted on a small batch and tracked for the entire growing period. If it works then the change can be implemented. If it doesn’t, they haven’t lost too much production, said Bittorf.
The conditions throughout the process are kept as clean as possible to keep out contaminants. The mushroom also carries its own defences.
“Once the mushroom fungus grows into the compost it becomes antagonistic toward any other moulds or competitors,” said Bittorf.
The mushrooms start growing as fuzzy white fibres that eventually join to form mushrooms.
Growers can’t predict atmospheric change and have noticed severe lightening storms affect the growth of mushrooms overnight.
“You might have forecast a 5,000 kilogram pick that day. Instead it’ll be like an 8,000 kg pick and I don’t know what it is,” said Bittorf.
Once mushrooms grow to the desired size, each bed is hand picked for either bulk boxes or smaller styrofoam packages for grocery stores.
Each picker measures and sorts the mushrooms as they are picked. The mushrooms are still picked by hand because it allows the company to leave the smaller ones and extend the growing season. Mechanical pickers gather everything, said Bittorf.
Mushrooms continue to grow after picking so they go into a rapid cooling unit that brings their temperature down to about 2 C. This slows the growth. Continued growth means mushrooms should be kept in paper bags rather than plastic so they can breathe and remain fresher for a longer time.
After the final picking the growing room is steam cleaned at a temperature of 72 C for 12 hours.
The used compost is hauled out and sold to gardeners. One week every year is set aside as gardeners’ appreciation day when crowds of 700 to 1,000 people arrive at the farm to pick up free compost.
There are five major mushroom growers, as well as a number of smaller scale growers in Alberta.
Moneys, Heritage and Tiger Mushrooms all grow white button mushrooms in southern Alberta and in the north, Superior Mushrooms grows white and browns while Prairie Mushrooms grow whites, portabellas and oyster mushrooms.
