Pruning the mushrooms

Update: Sadly, Continental Mushroom is now out of business.

Did you know that if you leave a package of mushrooms on the kitchen counter, the mushrooms will continue to grow? Or that portobello mushrooms are really just large, brown cremini mushrooms?

You can learn these and other mushroom facts at Continental Mushroom, a large mushroom growing farm on the eastern edge of the city of Ottawa. While not a tourist destination per se, Continental Mushrooms provides guided tours of the facility to interested groups and individuals.

Continental Mushroom is a great Canadian success story. The founder, Nicholas Pora, was a Romanian refugee from WWII who came to Canada in 1950. After working at mushroom farms in Ontario and Quebec, he founded Continental Mushrooms in 1972. Since that time, the business has grown to 250 employees, and now grows 200,000 pounds of mushrooms per week.

As you will discover on your tour, commercial mushroom growing is a challenging and labour intensive business. The process begins with top quality mushroom compost. Contrary to what I thought before I took the tour, mushroom compost does not consist primarily of manure. In fact, chicken manure is only a small part of the overall mixture. The compost is mostly hay or straw, mixed with peat humus and a few other natural materials. During an approximately one month long process, the mixture reaches its ideal state for growing mushrooms. Oh – and don’t worry about that chicken manure – the compost is “pasteurized” through steam sterilization, which kills all organisms, including any bacteria.

The next step is to add the mushroom seeds (called “spawn”) to the compost, and then load the soil into one of the 34 growing houses. Each growing house has 3 floors, with 4 growing beds per floor, giving Continental Mushroom more than 250,000 sq. ft. of growing space. During your tour, you’ll be able to go into one of these houses and see how the mushrooms grow.

The growing houses are dark, humid, and warm – and buzzing with activity as the employees tend to their harvest. The mushrooms grow quickly, with each harvest taking only 5-6 days. During that time, the mushrooms must be pruned regularly, or they’ll grow into big square clumps.

After the first crop is harvested, more mushrooms are allowed to grow from the same soil. Each load of compost provides three harvests, and then the compost is removed, the area is sterilized, and the process begins again.

Your tour may include a walk through the packaging and shipping facility. This is where the harvested mushrooms are cooled (to stop the growing process) and packaged for shipping. Then it’s off to the stores, where the mushrooms arrive no more than one day after they were picked. Because the shelf-life of mushrooms is so short, they are the ultimate local food – it’s simply not possible for long-distance producers to deliver the mushroom in such a short timespan after picking.

If you want to buy some mushrooms straight from the farm, just ask your tour guide. Choices include button, cremini, and portobello mushrooms. (They can also order in specialty mushrooms, including wild mushrooms such as morels.) If you’re looking for recipe ideas, have a look at the Continental Mushroom website, where there are more than 75 mushroom recipes, and lots of information about mushrooms in general.

Location: 2545 9th Line Rd, Metcalfe

Phone Number: (613) 821-1411

Web site:


Reservations: Required for tours.

Hours: Mushroom compost can be purchased Monday to Saturday from 8am to 4pm. Hours for guided tours vary (call ahead).

Cost: Tours are free.