Keeping the Plants Comfortable.
Light and heat are essential to growing tomatoes in Maine. We do our best to limit energy use, relying on nature to provide heat and energy when at all possible.
Don’t Leave the Lights On
Nothing beats sunshine. But when you grow tomatoes year-round, a little help goes a long way for the plants…especially during the short days of winter.
We use highly efficient grow lights specially designed to give the “right” type of light to the plants: they glow yellow, not the bright white of standard household bulbs. That said, these highly efficient lights are no match for the sun. One hour of bright sunshine is equal to several hours of light usage.
We do not run lights year-round, nor do we keep them on all the time. The plants have to go through a natural cycle that includes periods of dormancy. Also, the bees we use to pollinate the crops need to think that it’s dusk to go back to their hives. Everyone and everything needs to sleep.
Electricity: Local and Renewable
Our electricity comes from our friends at Madison Electric Works, a locally owned utility that works closely with us on our energy strategy.
In 2011, half of Maine’s net electricity generation came from renewable energy resources, with 25 percent from hydroelectricity, 21 percent from wood, and 4.5 percent from wind. There are 111 hydroelectric dams in Maine that supply electricity the grid, so the electricity source in our backyard is local and renewable.
We also strive to use electricity during “off peak” periods. We are able to give our plants the light they need without overtaxing the system during the peak summer cooling season. This works for us and for the community.
Always Tomato Season: Heat Management
To keep our greenhouses between the ideal 69 to 72 degrees, we run heat through a series of hot-water pipes. One set of pipes runs along the ground where we run our picking carts; the other is about three-feet above the gutters. To heat the water, we have three natural-gas boilers which also can run on propane or diesel. This heat is supplemented by heat given off by our grow lights.
In order to make the most of our heat, the entire greenhouse has retractable screens covering the walls and ceilings. This helps not only to keep in the heat, but also reduces light pollution.
Plants love hot sunny days and cool nights. We typically try to drop the temperature in our greenhouse by 10 degrees at night. We do this the same way most people cool down at night in Maine – we open the windows! This allows the plants to cool, the tomatoes to size up and everything to maintain a healthy balance.