Even In the coldest days of the season here, for some people imports can’t compare to freshly grown local produce, which can only be grown in a greenhouse just now.This time of year, light and heat management in local greenhouses is a priority. While larger indoor growing operations are moving to the use of artificial lighting – this according to a Farm Credit Canada (FCC) report using data from the federal government, McGill University, GE Lighting and tomato company Savoura – smaller growers continue to rely on traditional methods.
“It’s certainly not the norm yet in the greenhouse industry,” said Stuart Horst of Floralane Produce in Elmira.
His greenhouse tomatoes, grown with natural sunlight and heated with a natural gas system, will be ready for harvesting in several weeks.
In winter, monitoring 24-hour average temperature is most important: too warm and the plant burns more sugar than it produces, says the FCC report.
Horst suggests too much warmth and not enough sunlight causes plants to over-stretch towards their light source, becoming thinner and weaker.
“It’s a big challenge. We just try to manipulate the plant so that it doesn’t stretch for light. We just keep the greenhouse cooler on those days – the plant gets very thin trying to find light. We run the greenhouse a little cooler and are satisfied with less growth,”
In lower winter light, Horst reduces the temperature in his acre of greenhouses, signaling plants to produce less energy, then on bright sunny days the temperature is ramped up to allow more growth.
“There’s very little artificial lighting that’s used in Canada, period. While it’s technology that’s been around for a number of years, we look at somewhere like Europe – where there’s more uptake on artificial lighting than there has been [in Canada] – they would be the leaders when it comes to utilizing the technology,” said FCC spokesperson Dave Orosz.
Also, more light doesn’t necessarily mean more fruit.
“There is no advantage in providing more hours of light per day, as an excess of light might result in a loss of yields,” said Audrey Boulianne, production coordinator at Savoura, a Quebec company specializing in greenhouse tomatoes.
Rather the artificial lighting, whether light-emitting diode (LED) lights or conventional high-pressure sodium (HPS) lamps could help Canada’s producers compete with producing countries with plentiful natural heat and sunshine. The FCC report notes there is a continued greater demand for fresh local produce, potentially fuelling the demand for artificial lighting to extend growing options. LED lights provide that option at a lower operating cost than traditional lighting systems.
That vision is a long way off for most Canadian producers, however. Emerging in Europe, so far LEDs are used experimentally in the United States and Canada for growing but are used widely now to light up homes, streets and holiday lights. The new technology may result in more economical use of space, increased yields and more efficient use of energy than HPS counterparts.
But how feasible is this technology for local, smaller greenhouse operations?
“It’s wildly expensive for a small grower, they’d have to be pretty big,” said St. Jacobs Country Gardens’ Linda MacLeod-Biglow.
For the plants she grows, a conventional greenhouse with natural lighting is enough; a more elaborate setup would be unprofitable.
“Let’s just say it’s expensive. I think it could add 50 per cent to the cost of a greenhouse. In general, there has not been a lot of uptake on growing crops under lights,” said Orosz.
There are about half a dozen or less artificially-lit growing systems in Quebec, Ontario, British Columbia and Alberta.
The reason? While cost is a main concern, it’s the “leap of faith” required for the change that gets to a lot of growers, Orosz added. The expensive investment may not yield profits until 10 to 15 years after installation.
“I’d love to have artificial lighting. It’s the cost – it’s a big thing. We figured natural lighting all along. It’s just when we start growing more and more year ’round, is when we start thinking artificial lighting. The harvesting part is not year ’round,” Horst said.
He has been in talks with fellow growers on the subject but so far an artificial lighting system is still off in the future. Instead Horst focuses on his tried-and-true natural methods and even as the greenhouse is closed until the new harvest comes in, his workers are caring for the plants soon to be ripe with red fruit.