Greenhouse automation: Saving time and money

Whether you’re looking at your greenhouse’s heating, ventilation or production equipment, automation continues to play a key role in the horticulture industry. When was the last time you took a hard look at how or where your operation might benefit from some of the latest innovations?

Economy of scale is always an important consideration, but even small and medium size operations can benefit from some of these technological advancements.

As new technologies have been introduced over the years, the green industry has improved. Glass greenhouses were replaced by poly-covered structures with inflated double-layered roofs (still a preference today for many operations). Polycarbonate panel construction was later introduced, offering even more energy savings with its air-lock insulation properties.

Energy Efficiency Developments

Commercial heating systems have evolved as well. Once at the mercy of less efficient boilers and furnaces, growers can now opt for newer, high-performance climate control systems that offer staging. This opportunity to program staged variables of heating and cooling throughout a 24-hour period offers even more energy savings.

Melissa Behn of Carlin Horticultural Sales in Milwaukee, WI, and Matt Krum of Advancing Alternatives of Lancaster, PA, work with greenhouse growers every day. We asked their perspectives on what they’ve witnessed in the industry over the years and their thoughts on where we’re headed.

Behn, a field representative with the horticulture and landscape supply company, said she’s worked with clients with growing ranges anywhere from a 20-by-28-foot greenhouse to multi-acre ranges. “With the lack of labor, customers are looking at ways to maximize their existing employees’ talents and letting automation take over,” she said.

Labor-saving mechanical equipment as simple as flat fillers with conveyor belts and multiple-shelf rolling carts are just a few of the cost-effective products used in most greenhouses today. Potting machines and tray or flat fillers improve production in all size operations. With brush systems that sweep and recycle excess media, plug trays to 12-inch pots and hanging baskets can be filled with consistent results. It’s one investment in automation that can pay for itself as the labor pool continues to decrease and salary costs rise.

Advancing Alternatives offers touchscreen environmental control systems, energy efficient vent structures and greenhouse supplies and construction materials. Krum assists growers in determining the most cost-effective improvements to their existing range or new construction project.

“Growers want to automate their temperature and environmental controls,” he said. “What we’ve found is that when a grower has the ability to automate the temperatures in the greenhouse, they benefit in terms of quality control. It’s one less thing they have to worry about. There are some trendy things out there right now, but changes have been subtle over the past few years.”

Natural Ventilation Movement

What areas has he observed growers focusing on for their operations? “In the past and to the present, it’s natural ventilation, mechanical ventilation, fans and louvers,” Krum said. “What we are also seeing these days are advancements where some folks out there are even using a geothermal approach to heating and cooling.”

With recent research and developments in terms of air movement, Krum explained how one new item impacts greenhouse efficiency: “The de-stratification type fans mix air from the bottom of the greenhouse to the top, blending both air movement and temperature throughout the greenhouse.” This is especially effective during the winter heating season, moving hot air away from the roof and toward the occupied floor of the controlled area.

How and where does a grower even begin when considering any of these improvements? Krum’s company suggests tracking your current energy consumption before converting to natural ventilation. Estimates are that during hot spring and summer days, shutters and fans run 12 to 24 hours per day in the attempt to maintain a cool environment. Transitioning to natural ventilation can help with costs associated with mechanical ventilation, but know what those costs are when making those decisions.

Solar Options

Photo courtesy of Advancing Alternatives of Lancaster, PA

Solar energy is another opportunity that can assist with ventilation in greenhouses without an electricity source. “We saw solar energy as an opportunity to automate a greenhouse that otherwise wouldn’t have that ability,” Krum said.

Often used in high tunnel production, interest is increasing in systems that don’t require running electricity to a location. He pointed out that these solar systems use DC (low) voltage and work well with the generation and storage of that type of voltage. “From there, it was just a matter of using a controller that could run with that type of input,” Krum said.

“Solar does have limitations in terms of expense and energy availability,” he advised. “All we are doing with climate control in that greenhouse that is powered by the sun is rolling up the sidewalls.” At this time, it’s not yet available to run other systems in a greenhouse.

Thermal Curtain Systems

When considering temperature control for thousands of square feet of greenhouse growing space, thermal curtains are just one of the shiny new objects. Often included in new greenhouse construction, curtain systems can also be retrofitted to an existing range.

Improving energy savings by as much as 40%, these systems create an environment in control of not only light but humidity and temperature. Crop quality is also improved as the curtains shade, cool and help with heat retention. Programed controls allow for the opening and closing of this equipment, saving operating costs in both summer heat and winter chill. You can even find systems with Wi-Fi capabilities, offering control from a smartphone, tablet or computer that can also send notifications of temperature variances.

Payback Periods

Be sure to ask about the payback period when investing in any of these energy saving systems. According to Bethany Reinholtz, project manager with GDS Associates Inc., payback periods can differ depending on the systems implemented and greenhouse facility. The Madison, WI, engineering and energy consulting company’s agriculture division offers varied services from evaluating where energy is currently used on a farm or greenhouse and ways energy can be saved to what the payback period would be on an investment.

“Most greenhouses that install automated controls that do not already have integrated automated controls would see a payback in two to five years,” Reinholtz explained. “For a year-round grower, it’s closer to two to three years.” (That’s the short answer – a more detailed process would include an energy audit for the greenhouse property.)

Incentives & Funding Opportunities

Jessica Mlsna, a certified energy manager with Focus On Energy, assists Wisconsin residents and businesses in identifying and implementing energy efficiency projects and potential incentive resources. The service company offers unbiased third-party technical assistance to customers of participating gas and/or natural gas utilities in the Midwest.

According to Mlsna, in 2022 Focus On Energy awarded more than $2 million in incentives to 880 agribusinesses to improve their energy efficiency. These projects, including greenhouses, totaled more than $3.5 million in annual energy savings on their utility costs.

Energy savings and payback depend on more than your local utility’s rate structure. When doing an assessment, they also evaluate equipment runtime, load on the equipment and equipment costs. Many states have comparable organizations that partner with selected utility companies to offer similar services. North Carolina State University operates the NC Clean Energy Technology Center, and their website, dsireusa.org, offers an interactive map of the U.S. with state specific information for renewable energy and energy efficiency incentives and resources.

USDA offers competitive grants for specific energy efficiency improvements. The USDA Rural Development office is accepting applications in 2023 for loan financing and competitive grant funding to ag producers and rural small businesses for renewable energy systems or energy efficiency improvements. Ag producers may also apply for new energy efficient equipment and new system loans for agricultural production and processing.

Before applying for any federal grant, however, it’s a good idea to know any qualifiers. Some of the applicant requirements for this program, for example, include a minimum percentage of gross income coming from agricultural operations as well as the location of the agribusiness.

For more information, find the Rural Energy for America Program Renewable Energy Systems & Energy Efficiency Improvement Guaranteed Loans & Grants/Rural America page at rd.usda.gov/reap.

From increased production efficiency of mechanized greenhouse equipment to thermal curtains and the ability to control heating and cooling systems from a smartphone, there are a lot of possibilities out there for your greenhouse operation.

by Gail March Yerke

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