KELLY MCEVERS, HOST:
If you have a garden, your tomato plants are probably just now getting started. But if you go to the store, you might seem ripe tomatoes that come all the way from Canada. Canada actually sends us more tomatoes, peppers and cucumbers than we send the other way. And that's despite all the vegetable fields in California and Florida. When our food and agriculture reporter Dan Charles realized this, he was surprised and decided to investigate.
DAN CHARLES, BYLINE: I drove across Ambassador Bridge from Detroit into Canada and headed southeast toward the city of Leamington. It was a chilly, slate gray day in spring, but within an hour, I started seeing the vegetable fields - all indoors. They were growing the inside vast, see-through structures made of glass or plastic. Some of them covered 50 acres. That's an area bigger than 30 football fields.
PAUL MASTRONARDI: The Leamington area probably has about 1,500 acres of greenhouse production.
CHARLES: This is Paul Mastronardi, CEO of Mastronardi Produce Sunset Grown, a big vegetable grower here. This is the main reason why Canada sends us so many tomatoes. It's the biggest concentration of greenhouses in North America. Mastronardi says it all came from a decision his grandfather made in the 1940s. Umberto Mastronardi had been growing vegetables here in open-air fields.
MASTRONARDI: He had a trip over to Europe and saw greenhouses in Holland and said, you know, that'll work in Leamington, you know? Let's get out of the weather controlling our destinies.
CHARLES: He could heat the greenhouses and grow vegetables for most of the year. The technology spread quickly through two different tightly knit communities in Leamington - the Italians and the Mennonites. Over the years, the greenhouses got bigger and more sophisticated.
MASTRONARDI: Watch you don't put your hands into the machine.
CHARLES: Paul Mastronardi takes me inside one of his company's greenhouses. It's comfortably warm in here. Endless rows of green tomato plants are suspended from wires. The vines reach 10 or 15 feet into the air.
MASTRONARDI: All the ripe fruit are basically at my waistline, and so there is no bending. There is no ergonomic issue for a worker anymore to harvest the crop.
CHARLES: And the roots are in this tiny little box.
MASTRONARDI: Yeah, that cube is just what we start the baby plant in, and then underneath is a larger bag.
CHARLES: That bag is full of crushed rock, just something for the roots to grab onto. Little plastic tubes deliver the water and the nutrients that the plants need. Mastronardi says from each acre of land, you'll get 10 or 20 times more tomatoes in a greenhouse like this than you'll harvest from an open field. It's still more expensive to grow tomatoes this way compared to open fields, but Dave Harrison, editor of Greenhouse Canada magazine, says greenhouses can charge more for tomatoes because the fruit is protected. You can treat it more gently.
DAVE HARRISON: I think greenhouse produce has always been seen as a premium product 'cause it's always picked at its prime. And I think consumers picked up on that very quickly - that it was very fresh. It had very, very good shelf life.
CHARLES: In recent years, Canadian greenhouse producers led the way into new kinds of tomatoes, like those little ones you can just pop into your mouth.
HARRISON: Now they've diversified so much into specialty - mini products - the mini tomatoes you see - the grape tomatoes, cocktail tomatoes.
CHARLES: The United States has not developed a big greenhouse industry because it didn't need to. It had all those warm weather fields in Florida or California. That is now changing, as American growers go after that high-end tomato market. Big, new greenhouses are now up and running in Michigan, Ohio and Texas, but many of the people running those greenhouses are Canadians who learned how in Leamington. Dan Charles, NPR News.
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