This is what climate protection looks like

High energy efficiency, lower costs

The Greenhouse that Grows Ideas

Ed Feenstra has more than one solution for PLEXIGLAS® 

Ed Feenstra likes to experiment. "I love anything technical," says the 46-year-old. Anyone who walks around the greenhouses at Feenstra Flowers in Ontario, Canada, soon sees what that means. Everywhere you look you see special technical features designed by Ed that make work easier. The white watering pipes above the beds of lilies, for example. Or the pipe system under the roof that is filled with hot water in winter to melt the snow.

"I'm always asking myself what could be done better," Ed says. This quest for improvement and perfect functionality led him to PLEXIGLAS®. He built his first film-covered greenhouse in 1992. "We had only just started our company and decided to use film because it was cheap." But Ed and his wife Frau Loraine were not satisfied: "The light yield was poor and we had big problems with condensation dripping on the plants." This meant the Feenstras had to wage a constant battle with botrytis, a fungal disease. And soon enough, the cheaper price no longer seemed cheap: "We had to replace the entire film every two years." Ed had long had his eye on the solution. His neighbor and friend Otto Bulk at "Rosa Flora" had already been using greenhouses made of PLEXIGLAS® since 1987, with all their advantages. Ed was familiar with these advantages because he had worked for Otto for several years before starting up his own company. In 2000, Feenstra built his first PLEXIGLAS® greenhouse, and has never looked back since: "Our lilies grow much better because of the 91% light transmission and our yield has improved."

The heat-insulating properties of PLEXIGLAS® are another advantage. Feenstra Flowers grows different varieties of lilies on a surface of 4,800 square meters beneath 16mm double-skin sheets. The demanding plants with fine-sounding names like Mero Star, Sorbonne, Siberia, Rialto and Yelloween need a constant temperature between 17 and 18 degrees Celsius. But the Canadian climate has hot summer days of up to 30 degrees Celsius and dark winters with temperatures that drop to minus 30 degrees. "The good heat insulation of PLEXIGLAS® means we need less energy to keep temperatures constant." Ed Feenstra adds: "For us, switching to PLEXIGLAS® was an investment in the future."

Meanwhile, he not only builds his own greenhouses from PLEXIGLAS®, but builds and supplies greenhouses to gardeners all over Ontario. "PLEXIGLAS® is safe, easy and quick to fabricate. It's real fun building a greenhouse with this material." Feenstra and his team of six employees glaze two greenhouses a day, using around 300 sheets. The construction team is called up more and more often, as the demand for units made from this material continues to grow. Feenstra stores the acrylic sheets in a unit measuring 2,000 square meters, and this is also glazed with PLEXIGLAS® because it helps to save energy here too. With a transparent roof, Feenstra can do without additional lighting. Part of the roof is made from PLEXIGLAS® HEATSTOP double-skin sheets whose special formulation reduces heat buildup indoors, so the rooms require no air conditioning in summer.

But Ed wouldn't be Ed if he hadn't thought up something more to do with acrylic. This year, he built a glazing bar system for DEGLAS. With this, he can offer customers who switch to PLEXIGLAS®  a modular solution. There is a growing demand for such solutions: "Our customers know that quality pays off," says Denny Therrien, Product Manager at Evonik CYRO Canada LLC in Toronto, the manufacturer of PLEXIGLAS® multi-skin sheet. Therrien has monitored the development of the system and is sure it will be successful in the market. 

It's obvious that Ed Feenstra is always coming up with new ideas. His latest brainwave is currently taking shape. "I kept looking for a way to use the scrap material left over from cutting sheets to size." On a long car trip, he suddenly had an inspiration: a heat recovery system for his greenhouses. This is based on the air cavities in the multi-skin sheets. From time to time, the excess moisture has to be conveyed out of the greenhouse. So far, this has been done by opening the windows to let in dry air. "Although that worked, we lost heat in the process," says Ed, explaining a problem that no longer exists. Using the leftover sheet material, he built a system where a fan on one side blows fresh air through the cavities toward the inside. The hot air goes out through the other side. Since the inlet and outlet cavities are next to each other, the incoming air is warmed by the outgoing air. "That saves energy because we need less heating." Ed is busy with the trials at the moment. “It looks promissing”, he says, and a unit of this type is probably soon to be installed in all Feenstra greenhouses. "We can't wait to see what he thinks up next," says one of his employees. Given Ed Feenstra's inventiveness, he surely won't have to wait very long.  


The story about the queen of pot plants is just one of the articles in the current issue of the Greenhouse Journal: PROFITABLE GROWTH UNDER ACRYLIC. Download PDF 

How much energy can you save with PLEXIGLAS®? Why not find out? more

The online video series presents climate-friendly projects with PLEXIGLAS®. more