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W&T Mushroom LTD

Guelph/Eramosa, Ontario

W&T Mushroom LTD

Mushroom producer near Guelph

★★★★★ 5(11 reviews)

W&T Mushroom LTD: From a Dilapidated Farm to 10,000 Pounds a Week

On the 6th Line in Guelph/Eramosa, Ontario, Witold Jaroszewski runs a mushroom operation that is a textbook example of what one person's determination can build over four decades. When Jaroszewski purchased the property in 1984, what he found was a dilapidated mushroom farm with just two small growing rooms. What exists today is a commercial operation producing roughly 10,000 pounds of mushrooms per week.

The Witold Jaroszewski Story

Starting a mushroom farm from near-ruins takes a particular kind of stubbornness. In 1984, the Canadian mushroom industry was dominated by a handful of large producers, and the idea of a small independent operator competing for shelf space in Southern Ontario's grocery market would have seemed impractical to most. Jaroszewski saw something different in those two broken-down growing rooms. He saw infrastructure that could be rebuilt and expanded, in a location with the right climate conditions and market proximity to make it work.

Over the following decades, he expanded the facility from two growing rooms to six, each measuring approximately 2,000 square feet. That is 12,000 square feet of controlled growing environment, purpose-built for the specific temperature, humidity, and air exchange requirements that commercial mushroom production demands. The growth was gradual and self-financed, the kind of expansion that happens when profits get reinvested rather than extracted.

What They Grow

W&T Mushroom focuses on cremini and portobello mushrooms, the two varieties that represent the largest share of the Canadian mushroom market outside of plain white buttons. Cremini and portobello are actually the same species, Agaricus bisporus, harvested at different stages of maturity. Growing both from the same production system is efficient, but it still requires careful management of harvesting schedules to ensure each product meets the size and quality specifications that buyers expect.

Producing 10,000 pounds per week of these varieties positions W&T as a meaningful regional supplier. That volume is large enough to serve grocery chains and food service distributors, but small enough that the operation retains the hands-on quality control that distinguishes independent growers from industrial producers.

The Guelph/Eramosa Connection

The Township of Guelph/Eramosa occupies a stretch of Wellington County between the City of Guelph and the village of Rockwood. It is agricultural country, with the rolling terrain and limestone bedrock that characterizes much of southwestern Ontario. The area has historically supported dairy farming and cash crops, but mushroom cultivation has carved out its own niche here, partly because the region's agricultural heritage means the raw materials for mushroom compost, particularly straw and manure, are readily available from neighboring farms.

The township has embraced its mushroom heritage. Local events like Mushroom Fest celebrate the agricultural identity of the community, and W&T Mushroom is a central part of that story. The farm also maintains a presence at Toronto's St. Lawrence Market, one of the oldest and most respected public markets in the country. Selling direct to consumers at St. Lawrence Market is both a revenue stream and a branding exercise, putting the W&T name in front of Toronto's most discerning food buyers every week.

A Perfect Rating Earned the Hard Way

W&T Mushroom's perfect 5-star rating across 11 reviews is not the kind of number that happens by accident. In the competitive Southern Ontario mushroom market, where buyers have plenty of alternatives, maintaining that level of satisfaction requires consistency in product quality, reliability in delivery, and the kind of personal relationships that only a family-run operation can sustain. Jaroszewski has built exactly that over 40 years, and the reviews reflect it.

During the pandemic, W&T demonstrated its community commitment by donating extra produce rather than letting surplus go to waste. That decision, reported in the Wellington Advertiser, revealed something about the values that drive this operation beyond simple profit.

You'll find W&T Mushroom LTD at 4949 6 Line in Guelph/Eramosa, Ontario.

W&T Mushroom LTD — additional photo
W&T Mushroom LTD — additional photo

Photos of W&T Mushroom LTD via Google Places

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Written by Andrew Langevin · Founder, Nature Lion · Contributing author, Mushroomology (Brill, 2026)

Growing Mushrooms?

Nature Lion supplies grain spawn, liquid cultures, and growing supplies to farms and home growers across Canada.