As winter approaches, many regions face the inevitable shift in weather conditions that come with this season. For commercial greenhouse operators, this means adapting operations to maintain warmth and productivity during the shorter, colder days. Fortunately, there are several innovative and cost-effective methods to keep your greenhouse both warm and well-lit. In this article, we’ll explore five effective strategies to prepare your greenhouse for optimal performance during the cold season.
1. Enhancing Greenhouse Insulation
Before we talk about equipment you can install to make your growing environment more insulated, we will first mention that the insulation capability of your greenhouse’s building envelope is crucial, particularly in colder climates, to minimize heating costs. After you have prioritized insulating your building envelope, thermal curtains, or energy screens, are an excellent addition for enhanced insulation.
These curtains, made from materials like polyethylene, polyester, and aluminum, are installed just below the greenhouse roof. They can be mechanically opened or closed as needed. During winter, these curtains play a vital role in heat retention, preventing warm air from escaping through the roof at night.
By effectively retaining heat, thermal curtains reduce the energy needed to heat the space, thus leading to significant cost savings. Additionally, they help maintain consistent temperature and humidity levels, reducing condensation and associated issues like mold and mildew.
2. Energy-Efficient Heating Solutions
Heating can be the most costly aspect of running a greenhouse in winter. Adopting energy-efficient heating systems is crucial for profitability during the colder months. Geothermal heating, technology that uses steady temperatures beneath the Earth’s surface to maintain a consistent temperature within the greenhouse, is an energy-efficient alternative to traditional heating methods. Geothermal systems can use either air or water to transfer heat between the greenhouse environment and the ground.
Other efficient heating options include infrared heaters, which directly warm plants without first heating the air. These are particularly cost effective in already insulated greenhouses needing extra warmth during extremely cold nights.
Biomass heaters can be another sustainable heating solution in regions where fuel materials like wood chips or pellets are readily available. Biomass heaters work by burning organic matter to heat the greenhouse space. A couple examples of this include installing a pellet stove in your greenhouse or, depending on how big your operation is, installing a wood chip boiler to heat water which can then be used to heat your greenhouse space through a central heating system.
Heat pumps, which work by extracting heat from the air or ground, offer another efficient solution. They are more energy-efficient as they transfer heat rather than generating it by burning fuel. When choosing a heat pump, it’s essential to select one designed for plant comfort.
3. Optimizing Supplemental Lighting
During winter, supplemental lighting is necessary to ensure adequate light for photosynthesis. Key considerations include the type of light, intensity, duration, and the light spectrum. LEDs are more energy-efficient compared to HPS lights and offer dimming capabilities for adjusting light intensity based on external conditions. Additionally, many utility companies offer rebates for commercial growers who switch to LEDs.
Understanding your plants’ lighting requirements, the daily light integral (DLI) provided by the sun in winter, and the intensity of your supplemental lights will help optimize your lighting strategy. In our blog, Quality v. Quantity: Which is More Important for Greenhouse Lighting Optimization, we provide integral equations for understanding your optimal number of supplemental lights and daily run time for your winter setup.
Another consideration is the spectrum of light (the color of your supplemental lights). We provide some general guidelines in the blog mentioned in the previous paragraph, but in general, artificial lighting should have between 3% to 15% of blue light, 30%-40% of green, and the rest red. While spectrum is important for plant growth, it’s more important that your plants are getting enough light in the first place.
4. Implementing Automated Control Systems
Adapting to changing outdoor conditions in winter is simpler with an automated greenhouse controller. This automated system maintains optimal temperature, humidity, airflow, and ventilation, reducing operating and labor costs.
Automated systems use sensors to monitor environmental conditions and control climate and mechanical systems accordingly. They ensure that plants receive the right amount of light, water, and nutrients, crucial for thriving in winter. Consistent growing conditions lead to consistent growth and high-quality crops.
5. Seeking Financial Support for Energy-Efficient Upgrades
There are a variety of ways that commercial growers can receive financial support for adopting renewable energy technologies or upgrading to energy-efficient systems. While financial support is helpful in any season, it’s often most beneficial in the winter when heating and lighting bills are higher.
For existing commercial growers who want to make energy-efficient upgrades to their greenhouse, consider applying for a REAP (Rural Energy for America Program) grant offered by the USDA. Under REAP, there is a program called Renewable Energy Systems & Energy Efficiency Improvement Loans & Grants that helps farmers save energy by financing greenhouse updates.
Commercial growers can also receive tax incentives and credits that are available for businesses that invest in renewable energy or energy efficiency improvements. This can include deductions for the cost of energy-efficient equipment and materials. If you add renewable energy technology, like a wind turbine, to your farm, you can benefit from both REAP grants and tax incentives, making an expensive piece of equipment relatively affordable.
Local utility programs may offer rebates and incentives for upgrades in lighting, building envelope, and HVAC systems. While rebates are typically more applicable to new projects, incentives can support enhancements like adding LED lights. LED rebates are usually the easiest to acquire since the energy savings calculations for this type of equipment are fairly simple.
Preparing your greenhouse for winter involves careful planning to maximize energy efficiency while maintaining productivity. For tailored solutions based on your specific location, climate, and growing goals, feel free to reach out to our greenhouse experts at Ceres.
Interested in winterizing tips for a residential greenhouse? Check out our blogs, 5 Essential Tips to Prepare Your Backyard Greenhouse for Cold Weather Cultivation and 3 Ways to Heat Your Greenhouse for Free this Winter.