It’s easy to do a three-season greenhouse. It’s also easy to do a four-season greenhouse provided one burns enough fossil fuels for heat during winter. The challenge that we undertook with this project is to do a four-season greenhouse that functions solely on renewables, i.e. no fossil fuels, and is off both the power and water grids. This experimental greenhouse will get all its heat and power from prototype roof- and wall-mounted BIPV-T arrays, developed by Montréal ZERO Inc.