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Dining & Wine

Giant Greenhouses Mean Flavorful Tomatoes All Year

Stacey Cramp for The New York Times

Some of the more than 500,000 plants at Backyard Farms at its Maine greenhouse. More Photos >

Published: March 30, 2010

Madison, Me.

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Stacey Cramp for The New York Times

Barbara LaRouche adjusts the position of the plants to get the best exposure to sunlight. More Photos »

AN icy mixture of rain and sleet fell on the glass roof of Greenhouse Two at Backyard Farms here, but as its big blue door slid open and the warm, green, celery smell of tomato plants wafted out, it was summer.

When it was built three years ago, the company’s first 24-acre greenhouse in Madison was already the largest building in Maine. This second connected greenhouse, completed last year, brought the total area under glass to some 42 acres, or roughly the size of 32 football fields. Even in the depths of winter, a million tomatoes ripen indoors to harvest each week, snipped from their vines by workers in T-shirts and shorts.

“It’s medium sized,” said Tim de Kok, one of the company’s head growers. At his last job, Mr. de Kok managed a 40-acre chunk of a 318-acre monster in Arizona. The center of Canada’s greenhouse industry, the area around Leamington, Ontario, has some 1,600 covered acres, roughly equivalent to putting Manhattan, south of Houston Street, under glass.

Once, if you wanted tomatoes out of season, you mainly had to settle for hard pink ones picked green in the fields of Florida or Mexico and shipped by truck. Commercial greenhouses could do better, but they were a niche market.

Backed by consumer demand for fresh tomatoes year round, the indoor acreage devoted to growing tomatoes has become nearly six times as large since the early 1990s, said Roberta Cook, a marketing economist who helped write what many in the industry consider to be the definitive report on greenhouse tomatoes in 2005.

Those tough pink ones are still good and cheap enough for most fast food restaurants and the food service industry, which buy about half the fresh tomatoes sold in the United States. But with shoppers willing to pay a premium — even $4 to $5 a pound — for red vine-ripened ones with more flavor, greenhouse tomatoes now represent more than half of every dollar spent on fresh tomatoes in American supermarkets, according to figures from the Perishables Group, a market research firm in Chicago.

“In the U.S., it’s hard to be competitive without a 20-acre minimum block,” Ms. Cook said.

The plants here at Backyard Farms number about 550,000. Each consists of two plants — the vines of new varieties, constantly tweaked for flavor, color, freshness and myriad other traits; and the roots of another, grafted together at a thickly scarred “V” near the base.

One half grows down into a sterile dirt-substitute made from fibers spun out of volcanic basalt, absorbing a custom hydroponic cocktail mixed by Mr. de Kok. The other half stretches toward the glass ceiling, growing a foot every week along a nine-foot length of twine. When the plants reach the top, workers reel more twine from the spool, shift the entire row horizontally and band each vine to its neighbor so that by the end of a plant’s life it might grow parallel to the concrete floor for as many as 20 or 30 feet, a dozen vines tangled together like garden hoses, before each makes its own graceful turn upward.

“It’s like a bonsai tree — you have to treat every plant exactly the same,” Mr. de Kok said. “As soon as it gets uneven, that’s when it starts to get away from you.”

He sat at his desk with three monitors recording temperature data, carbon dioxide levels, light readings measured in joules per square meter, and countless other figures from sensors scattered throughout the glass building.

To compete in a more crowded market, where increased supply eroded price, many exploit technology to scramble for tomorrow’s hot tomato.

“There is a tremendous variety of tomatoes available, thousands of cultivars,” said Tom Papadopoulos, a senior research scientist at Canada’s Greenhouse and Processing Crops Research Centre in Harrow, Ontario.

In the mid ’90s, beefsteaks were the dominant contributor to greenhouse revenue. Then it was tomatoes sold on the vine, the principal crop at Backyard Farms. They are medium-size fruit, round and firm, and are sold in clusters of four to six.

Today, as tomatoes on the vine grow commonplace, many companies are going small — cherry tomatoes, or grape, or campari, larger than cherry and smaller than tomatoes on the vine. Backyard Farms recently introduced a new line of cocktail tomatoes on the vine, similar in size to Camparis and sold in clusters of eight and packaged in cartons like Tomato McNuggets.

“They’ve got strawberry tomatoes in greenhouses now — that’s a special variety that also has great flavor,” Ms. Cook said. “What I find is the smaller ones tend to be the good ones.”

While the diversification is industrywide, the ability to grow many generations of greenhouse plants in a single season allows breeders to introduce those varieties more quickly, Mr. Papadopoulos said. Advances in genetics have allowed breeders to cross-pollinate precisely for control over specific attributes like size, color, disease resistance, firmness for shipping and levels of acids and sugars, the balance of which accounts for the bulk of a tomato’s flavor. Too little sugar turns fruit tart. Too little acid turns it bland. Too little of both leaves tomatoes with little flavor.

As tomatoes ripen on the vine they develop more of those sugars and acids and other flavor elements. But most of the major farms growing tomatoes that are sold fresh year round are in areas where the climate is more hospitable to varieties best picked green.

By creating their own climate — whether in Arizona, Maine or Canada — greenhouses allow growers to pick and ship tomatoes only when they’re ripe.

That’s a major advantage. And while no one would mistake a Backyard Beauty for a tomato picked from a backyard in late summer — it is not as tender and its flavor is not as complex — it is juicier and has much more flavor than what you’d find in your deli sandwich.

“They don’t make a tomato that my grandmother would have liked,” Mr. Papadopoulos said. “They make a tomato that my son would like or my daughter would like.”

Some of the technical advances that have allowed for these changes don’t even seem like technology.

Twenty years ago, the millions of blossoms on these vines would all have been pollinated by hand, electric vibrators shaking pollen loose from anther to pistil every 48 hours. Today, that work is done by bees, shipped in cardboard hives from Michigan that are stacked seven high at the end of the rows.

Aphids, when they’re found, are kept in check by a small species of wasp, no bigger than a flying ant, that lays its eggs in the pest’s larvae.

Lately, the greenhouse has been experimenting with interplanting young plants alongside older ones so that when one generation is discarded, the next is already yielding fruit. The aim is a continuous flow of production, tomatoes ripening fully on the vine year round and landing in outlets as far away as Maryland within 24 hours of harvest.

“Continuous production cycles, that is important now as the market becomes more competitive,” Mr. Papadopoulos said. “If they’re out of production for two months, people who buy tomatoes will go somewhere else, and maybe they will forget to come back.”

For instance, the majority of growers in Canada’s greenhouse capital, Leamington, are unable to produce the year round because, experts say, there simply isn’t enough light to grow tomatoes there profitably in midwinter.

Backyard Farms is some 130 miles farther north of that Canadian city. To compensate, it employs some 20,000 high-pressure sodium lights, fueled by cheap power from Madison’s town-owned hydroelectric plant. Switched on, the lights use as much electricity in 32 minutes as the average American household does in a year. Some of its 200 employees wear sunglasses.

The environmental costs of pouring so many resources into a tomato is a touchy subject. Backyard Farms’ chief executive, Roy Lubetkin, when pressed, pointed to biological controls like the wasps that allow the company to grow tomatoes without pesticides, and to the four-acre reservoir of reclaimed rain runoff that supplies, almost exclusively, their irrigation water. And because there is no dirt at Backyard Farms, fruit needn’t be washed.

“It’s real sunlight, it’s real rainwater, these are real bees,” he said. “What we’re really doing is allowing nature to do its thing.” But which is greener, a field tomato shipped to Maine from Florida or one grown in-state in a greenhouse? “We’re redder,” he said.

Across from the four-acre reservoir of recycled runoff, hidden from the road, are three very large propane tanks that serve a boiler system that keeps temperatures hovering around 70 degrees year round.

Two enormous tanks, filled with carbon dioxide, stand on end beside them. The gas, fed along the vines in perforated plastic bags, adds bulk to the fruit and speeds growth. The tanks suggest that greenhouse tomatoes, while delicious, aren’t particularly green.

Such were the findings of a 2005 study by the British government that compared the ecological footprints of tomatoes grown locally in heated greenhouses with those grown in fields and imported from Spain. Even taking into account emissions from an additional 700 miles of shipping, the local greenhouse tomatoes were still responsible for emitting nearly four times more greenhouse gases than the imported fruit. Barring some advance in heating or lighting, or possibly even in the tomatoes themselves, such is the cost of perpetual summer.

Inside at Backyard Farms, the bees zip around the crates, workers and tomato vines that stretch on to the faint glass horizon. Through a door at the end of Greenhouse Two, pallets of tomatoes are boxed and ready to be loaded onto a truck. On this morning, they were suspended from their vines. By this time tomorrow, they’ll be back indoors, under supermarket lights.

An earlier version of this article referred incorrectly to a variety of tomato being introduced by Backyard Farms. It is a cocktail tomato on the vine, not a cherry tomato on the vine.

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