Greenhouse Tomatoes

I've become a bit obsessive about the myths of vertical farming, emphasizing that plants need sunlight. And I noted the White House garden was much less productive in the winter than the other seasons. So as I read today's NYTimes piece on greenhouse tomatoes I was becoming worried.  Backyard Farms, in Madison, Maine has 42 acres of greenhouse, in which they grow tomatoes all year round!

An excerpt:

 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.

The article goes on and on describing the varieties, the culture, etc.--all of it very interesting. The tomato vines, which must be indeterminate varieties, grow to tremendous lengths.  It's only in the last third that the writer addresses the problem of light. As a side note, Leamington, Canada has 1,600 acres of greenhouses and it is further south than Madison. But the Canadians can't grow tomatoes in the winter.

I was relieved to read this:

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. 

And the writer closes by noting a British study that compared UK greenhouse tomatoes to ones grown in Spain, and found the greenhouse ones accounted for four times the carbon emissions as those shipped from a distance.