DIY: Sustainable Greenhouses
There's no getting around the fact that greenhouses consume resources, but making the correct choices when you design, build and run your own greenhouses can make your growing operation a responsible one. Building with environmentally friendly materials, designing energy-efficient greenhouses and using resources responsibly in the operation of the greenhouses are all do-it-yourself decisions that contribute to greenhouses' sustainability.
A typical greenhouse operation is a voracious consumer of plastics and other environmentally unfriendly materials, from the plastic film covering on many do-it-yourself greenhouses to the plastic packaging of soil and fertilizers. Choosing recycled or recyclable materials whenever possible, both in the construction of greenhouses and in their everyday operation, is one way to run sustainable greenhouses. Reusing or recycling planting pots, trays and packaging also lessens greenhouses' environmental impact.
Passive Solar and Thermal Banking
By their very nature, greenhouses are good at collecting energy from the sun and using it to heat their interiors to the appropriate temperature. Passive solar design, which is used in most greenhouses, doesn't use mechanical or electrical devices to capture solar energy but simply uses a building's structure to collect and store the energy. Allowing for adequate control of ventilation when you design greenhouses minimizes the need for fans and other energy-consuming cooling solutions. Collecting and storing solar heat for later use is a process known as thermal banking. A thermal-banking system that uses the sun to heat water and then stores the water underground, where it can be used to heat the greenhouses in cooler weather, is an ambitious do-it-yourself project, but it helps to make the operation of greenhouses more sustainable than it would be otherwise.
A greenhouse operation uses a lot of water, and one of the most effective ways that you can make your greenhouses more environmentally friendly is to adopt sustainable irrigation practices. Consider collecting rainwater from the gutters on the greenhouses or on other buildings on your property, then using a gravity-fed distribution system to move the water to storage tanks for use in your greenhouses. If you have a pond on your property, it also can be a convenient source of water for irrigation that has a low environmental impact. Building a rainwater or pond water collection and storage system is a project that is well within reach of a resourceful do-it-yourselfer.
Sometimes it's necessary for a greenhouse to consume energy, but making simple changes can minimize its energy consumption. For example, replacing incandescent lighting with fluorescent fixtures significantly reduces the amount of energy consumed by greenhouse lighting, and replacing fluorescent fixtures with high-efficiency sodium vapor lighting, although more expensive initially, may increase energy savings even further and provide more effective grow lighting for plants at the same time.
Evan Gillespie grew up working in his family's hardware and home-improvement business and is an experienced gardener. He has been writing on home, garden and design topics since 1996. His work has appeared in the South Bend Tribune, the Fort Wayne Journal-Gazette, Arts Everywhere magazine and many other publications.