Mushrooms

WHAT ARE MUSHROOMS?

Mushrooms are a fungus. Other mushrooms grown in BC are the Shiitake, the Oyster and the Wild Pine mushrooms. The most common mushroom that is grown in BC is called Agaricus bisporus, or button mushroom, and comes in 3 colours -- white, creamy, and brown.

WHERE ARE MUSHROOMS PRODUCED IN BC?

The majority of mushrooms are grown in the Lower Mainland. There is some production on Vancouver Island and elsewhere in the province.

HOW MANY MUSHROOMS DO WE PRODUCE?

Mushrooms are BC's second most valuable edible horticultural crop, after apples, with retail slaes estimated at $50 million. BC supplies almost all of its own mushrooms. About 93% of mushrooms eaten are grown here. There are approximately 60 producers who grow 15 million kg of mushrooms. About 65% are eaten fresh; the other 35% are processed. BC produces about 25% of all mushrooms grown in Canada. About one-half of the mushrooms grown here are eaten here. The other half is exported to other provinces, the United Stated or as far away as Japan.

HOW ARE MUSHROOMS PRODUCED?

Mushrooms are grown in special insulated houses. These houses consist of a number of growing rooms in which growing conditions are closely controlled, often by a computer. At each stage of the mushroom cycle, the grower must carefully control the temperature, moisture levels, light levels and air movement. Because mushrooms can be afflicted with a variety of diseases and insect pests, growers must control the spread of these. They also monitor who goes into the growing areas. Mushroom growing rooms consist of 5 to 7 tiers of wooden frame beds on either side of a central aisle.

Mushrooms are grown in a type of soil called compost. Mushroom compost is a mixture of hay, straw, horse manure, gypsum and any one of several nitrogen containing compounds. In BC, most of this compost is prepared by the Fraser Valley Mushroom Growers Cooperative. Compost needs to be pasteurized to destroy the pest and disease producing organisms. To pasteurize, the compost is put into the wooden frame beds. It can heat naturally, but some heat is generally used to raise the air temperature to the 40 to 47° C range. To ensure rapid pasteurization and conservation of nutrients, the compost temperature should be held in the 52 to 57° range during the first 3 days. Mushroom spores are then sprinkled by hand on the compost. This is called spawning. 10 to 14 days after spawning a greyish white growth will appear on the surface. A casing soil, mainly peat and ground limestone, is put on the white growth. This soil is kept damp. Mushrooms first appear as pins, and then grow larger.

Mushrooms are ready for harvest when the veil across the top of the mushroom is stretched tight, approximately 3 to 4 weeks after casing. Subsequent flushes of mushrooms appear every 7 to 10 days. Growers will typically harvest only the first 2 flushes. The whole cycle takes 8 to 12 weeks and growers have 5 to 7 cycles per year. At the time of picking, mushrooms are graded. 80% of the mushrooms picked are graded No. 1 which means the mushrooms are unblemished and without discolouration, the veil on the cap is stretched tight without cracks or tears, and the mushrooms are a normal shape. Mushrooms are put in cold storage with a constant humidity.

The used mushroom compost is often sold to nurseries or garden suppliers and used for soil enrichment.

WHAT DO MUSHROOMS LOOK LIKE WHEN I USE THEM?

Mushrooms are either eaten fresh or they are canned. They are a popular topping on pizza. You'll see them in salads, in hamburgers, as a side dish with steaks, in sauces, in soups or in stews. They are a fairly good source of iron, potassium and the B vitamins.

WHAT HAPPENS AFTER THE MUSHROOMS LEAVE THE FARM?

Mushrooms should be refrigerated. They will keep about 5 days after being harvested. In BC, most mushrooms are picked by hand, packed into boxes, trucked to the co-op and shipped to market within 24 hours. Mushrooms are usually managed through either Money's Mushrooms, the marketing end of the Fraser Valley Mushroom Growers Cooperative, or Pacific Fresh Mushrooms Inc. Some of the mushrooms that are to be processed are canned at the co-op or made into products such as mushroom soup.

WHAT CHALLENGES DO MUSHROOM PRODUCERS FACE?

Operating in an environmentally responsible manner, producing a product that is free of imperfections and diseases.

WHO'S INVOLVED IN PRODUCING MUSHROOMS?

• Compost preparers
• Mushroom producers
• Truckers

Interesting Fact About Mushrooms:

A British Columbian eats more mushrooms than anyone else in Canada. Each person eats about 3 kg per year, while the average Canadian eats only 2 kg per year.

Contacts and other resources:

 

BCMAL - Mushroom Information

British Columbia Mushroom Marketing Commission