Greenhouses, although already fairly eco-friendly, can still be improved to be more sustainable and have greater efficiency. If you’re designing a new greenhouse or planning on renovating your current greenhouse, here are some tips and ideas that will take your greenhouse to the next level of sustainability.
WHAT IS A SUSTAINABLE GREENHOUSE AND WHY IT MATTERS Greenhouse gardening is an efficient way to grow food on a relatively small piece of property without compromising soil quality. Greenhouses help keep surrounding areas undisturbed, preserving the ecosystems and wildlife that live there. Compared to conventional farming, growing in greenhouses is a more sustainable method of food production. But if designed without sustainability in mind, greenhouses can be quite energy and water intensive. From their construction to operation, sustainable greenhouses are designed to preserve resources and have a low environmental impact.
SUSTAINABLE GREENHOUSE DESIGN Designing a sustainable greenhouse involves:
Selecting the right site Designing the right structure Building with sustainable materials Implementing an eco-friendly watering system Following the 3 R’s: Reduce, Reuse, Recycle Optimizing energy usage STEP 1: SELECT THE RIGHT SITE Choosing your location for your greenhouse is not only your first step in the design process but arguably the most important because it can be an expensive and wasteful mistake. Estimates show that more than 80 percent of energy used for greenhouses goes toward heating , especially during the winter where growers use heaters throughout the season to maintain a temperature at 65ºF. Therefore, a greenhouse should be designed with the goal of getting as much light and natural heat as possible for your plants. This will help to save energy on lighting for off season and will make it a prime spot to place solar panels. To maximize available sunlight, it is recommended that placement of the greenhouse is along an east-west orientation with the longest side facing south . Of course this all depends on geographic location, so consult this chart to find the most accurate placement information depending on your latitude.
STEP 2: DESIGN THE RIGHT STRUCTURE Designing your greenhouse with the right shape and structural features is also critical for maximizing sunlight and reducing energy costs. Modular construction, or prefabricated construction, saves time, money and energy by almost 70% during the construction process. Given that modular units have already been tested for efficiency and durability pre-install, you can be certain of its performance once it reaches your property.
It is also important to consider flooring design. A compacted soil foundation is cheap, natural and easy to “install”. The porousness of dirt allows for water runoff to pass through without much effort or adjustments. However, this is best for smaller, temporary greenhouses. Larger, heavier structures will settle, potentially warping and breaking its structure. Gravel as a ground cover drains well and widely available.
Larger, more permanent facilities should consider cement slabs, wooden decks or stone or brick paved foundations. Each of these options offers long-lasting durability but each comes with its own pros and cons. While cement foundations are easy to clean and install, they’re also more expensive, offer no drainage, and can act as a heat and cold sink, imbalancing indoor temperatures. If you choose a cement foundation, be sure to install a centralized drain that exits outside the walls of your facility to avoid unnecessary moisture and water buildup.
Stone or brick paved foundations offer more drainage via the cracks between pavers and some stones retain heat better than others. Depending on your seasonal needs, this can be an inexpensive way to heat your greenhouse.
Wooden decks could be your most sustainable option if you source from a sustainable lumber company. Wood is easy to clean and offers optimal drainage. It offers poor insulation though due to the open air underneath the greenhouse.
The foundation you choose really depends on your climate. The key objective is to select a foundation that optimizes natural temperature and moisture regulation.
Also, be sure to know your building codes and contact your local environmental protection agency to ensure you’re complying with water runoff policies, especially if you plan to use pesticides or fertilizers (including green, non-toxic brands).
STEP 3: BUILD WITH SUSTAINABLE MATERIALS When constructing the metal framing it is critical to choose the right type of metal to withstand the weather elements in your area. Consider using forged metal that has 37% higher fatigue strength and is able to withstand long-term wear.
Look into eco-friendly greenhouse panels and coating options. Ideally, invest in glass panels instead of plastic. Not only is glass more effective at retaining heat, glass is more durable long-term and can be recycled. Even if your collection facility accepts plastic greenhouse panels, plastic deteriorates under the natural elements and may not be in the best condition for recycling.
Besides adding some decorative color to the outside of your greenhouse, coatings are important for sunlight and temperature control. There are various types of coating purposes – shading, diffusion, transmission, reflection – depending on the amount of sunlight and heat you want inside your greenhouse. Buy a product that serves both purposes – decoration and sunlight/temperature control. Also, look for low- or no-volatile organic compound (VOC) options to prevent the release of harmful chemicals into the atmosphere.
STEP 4: IMPLEMENT A SUSTAINABLE WATERING SYSTEM Implementing a sustainable watering system conserves water while saving you time and money. Different watering and irrigation tools can be incorporated including soaker hoses, moisture meters and water reservoir systems. A good alternative to hoses, drip irrigation can reduce water use by 30 to 70 percent compared to conventional sprinkler irrigation. In addition, drip irrigation more directly and efficiently waters plants, thus creating less labor for you.
The most sustainable solution to greenhouse irrigation is to use natural water resources as your primary source. Irrigation pumps can reach water wells and natural streams or ponds nearby, but local water tables will dictate how much you can use. Rainwater collection is a great option as it is free and utilizes a water source that is all too often wasted.
STEP 5: FOLLOW THE 3 RS: REDUCE, REUSE, RECYCLE Reduce, reuse and recycle to help conserve resources and eliminate unnecessary landfill waste. When choosing building materials, consider repurposing materials or using those made from recycled content. This could be using reclaimed wood for plant bed frames or greenhouse anchors. Reclaimed granite or brick pavers is another way to avoid buying new.
Reduce your plastic waste by reusing pots, planters and seed starters. You can also reduce your water waste by repurposing grey water for gardening purposes.
STEP 6: OPTIMIZE ENERGY USAGE When designing or renovating your greenhouse, it is important to consider energy efficiency . Modular “plug-and-play” wiring systems reduce both energy usage and installation time, making them the optimal choice for lighting your greenhouse.
Optimize for natural lighting and install LEDs. If additional lighting for heating is needed, LEDs also serve as effective heat lamps that consume a mere 14 W of electrical power per lamp. Solar powered pathway lights are also a great addition to your greenhouse.
Depending on your location, solar power can be an effective way to power anything in your greenhouse that needs electricity and you can install panels in a way that does not interfere with the natural beauty of your nursery. Check out Lavender Pond Farm , New England’s largest lavender farm, and their solar SmartFlower, the first all-in-one, plug-and-play photovoltaic solar system.
A “solar flower” at Lavender Pond Farm, New England
Given that greenhouses are designed to optimize sunlight, they are a prime structure for installing solar panels. Before building your greenhouse, consider how much energy you will need to run the various operations in your greenhouse and consult a local solar company. If your area has high winds, small, onsite wind turbines are another renewable option for powering your greenhouse. Whether you choose to go solar or wind, you will require a permit for installation. If working with a contractor, they should be knowledgeable on which permits you’ll need but if this is a DIY project, you’ll have to contact your local building and permitting agency.
CONCLUSION: CREATE A SUSTAINABLE GREENHOUSE TO HAVE A POSITIVE IMPACT If you want to take your greenhouse to the next level and enhance its sustainability, make sure to keep these tips in mind when designing and running your greenhouse.
Select the right site Design the right structure Build with sustainable materials Implement a sustainable watering system Follow the 3 R’s: Reduce, Reuse, Recycle Optimize energy usage While building a sustainable greenhouse has several upfront costs, its resource-efficient and practical design will save you money and time, while also benefiting the environment in a positive way. Your sustainable greenhouse should be energy- and water-efficient, made wisely with sustainable materials, and should avoid disturbing surrounding ecosystems and wildlife.
