With rapidly dropping temperatures — and even some frost — we're getting to the end of the harvest here in southwestern Ontario.

But there's a farm in Leamington that has no intention of slowing down. In fact, they work all year round, 365 days a year.

Highline Mushrooms is one of the largest mushroom growers in the country, with three farms in Essex County — one in Kingsville and two in its home base of Leamington. I was given a tour of the company's west Leamington farm by manager Will Peters, who's been with the company for 22 years.

The first stop on the tour was a place called "the wharf."

Here, straw, gypsum and chicken manure are combined to make the nutrient-rich substrate that mushrooms are grown in. The composting process naturally heats the material to 80 C — even in the dead of winter, which is why you can see steam rising from the piles.

After 14 days, the substrate is loaded into giant chambers Peters calls "tunnels."

Over the course of five days, the substrate is pasteurized to kill any unwanted bacteria, mold and insects.

Grain that has been exposed to the particular mushroom fungus strain is added to the material and incubated in the tunnels for two more weeks.

This enriched mixture is then transferred into a giant growing room. Each bed is topped with a layer of peat moss, which is the black stuff you may occasionally see in a package of mushrooms — contrary to popular belief, it's not manure. This top layer is where the mushrooms are harvested from.

After another two weeks in the growing room, the mushrooms are ready to be harvested — and they don't stop coming.

Should I wash my mushrooms?

According to Peters, all you need to do with your mushrooms is wipe them with a damp paper towel. Mushrooms easily absorb water, so washing isn't recommended.

At its peak, workers may harvest a room up to 5 times each day to keep up with the rapidly growing fungus.

Can't see the GIF? Click here.

The Leamington farm produces both white and brown (crimini) mushrooms. Portabella mushrooms are grown here as well, as they are simply crimini mushrooms have have been allowed to grow larger.

After the mushrooms stop growing, the substrate — along with any trimmed stems — is sold to local farmers for use in their fields.

"We're essentially an enormous recycling company," Peters said.

The mushrooms are then transported to the packaging room, where they are packed under the Highline label, as well as familiar store brands. While every mushroom produced at this farm is certified organic, mushrooms from conventional farms are also packed at the Leamington facility — so not every package gets an organic label.

Slicing happens in this room as well.

The mushrooms then hit the loading dock and make it to a grocery store near you. If you happen to be in Leamington, you can buy them directly from the farm, located at 506 Mersea Road 5.

CBC Windsor reporter Jonathan Pinto travels across southwestern Ont. in search of the tastiest food stories.

Know of a place you think he should check out? Email jonathan.pinto@cbc.ca or tweet @jonathan_pinto.

Jonathan Pinto is the host of Up North, CBC Radio One's regional afternoon show for Northern Ontario and is based in Sudbury. He was formerly a reporter/editor and an associate producer at CBC Windsor. Email jonathan.pinto@cbc.ca.

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