The greenest greenhouse in the world?
11 November 2008
An American entrepreneur has engineered the first sustainably-heated private greenhouse in his back garden, heated almost entirely by naturally-generated energy.
Mark Veeder works as an events production manager in New York City during the week, but at weekends retreats to his large woodland garden in Sullivan County, two hours' drive north of the city. There, he becomes what he refers to as “an obsessive gardener” - developing his interests in Echinacea breeding and South African plants.
Sullivan County is USDA Zone 5 – meaning temperatures regularly drop to a punishing -25°C (-13°F) or so in winter. It was crucial to protect his beloved plants through the coldest months of the year, yet, as Mark puts it, “greenhouses are energy hogs”. The dilemma over how to heat a greenhouse without incurring high environmental and financial costs led him to design and build his own eco-friendly greenhouse.
“I just totally over-engineered this,” says Mark. “I wanted to do something which has never been done like this before, and I wanted it to be as green and sustainable as possible.”
The greenhouse is large, at 6m x 12m (20ft x 40ft), and is set into a south-facing hill. Mark started by digging out the hill, and then lined it with insulated concrete forms (ICFs) – hollow styrofoam blocks filled with concrete, which form a 6m (20ft) wall behind the greenhouse. This acts as a giant heat storage device, as the wall heats up in sunlight during the day and then releases it slowly through the night. The ICFs act as insulation, and also conduct heat through water pipes in the floor. There is a back-up from a fuel-efficient oil burner, but Mark is hoping to keep its use to a minimum.
Mark does admit that its size helps the structure to work well.
“Since it's such a big mass the heat is pretty constant,” he says. “It's on a big scale, but I think the theory is good and could be used in small gardens.”
The insulation works to keep the greenhouse cooler in summer, too. In 2008 Mark recorded temperatures of 35°C (95°F) outside but inside the greenhouse, he says, it was a constant 10°C (50°F) without fans. His design has yet to be tested through the full rigours of a New York State winter, but if it does fulfil its early promise, it could offer a solution to gardeners with energy-hungry greenhouses everywhere.