Greenhouse Cooling: 7 Tactics to Survive the Heat

Pad-and-fan evaporative system used in a flower greenhouse for cooling.

Seeking solutions for greenhouse cooling to combat the sweltering summer heat? You’re in good company.

As the calendar flips to the hottest months of the year, finding ways to maintain optimal growing conditions inside their greenhouses becomes a top priority for many growers.

We have you covered. Here are seven tried-and-true tactics for greenhouse cooling to increase your cooling efficiency and protect your plants.

1. Keep Air on the Move

Proper ventilation, whether passive, active, or a combination of both, promotes the healthy exchange of air between the inside and outside of a greenhouse. It ensures your plants get enough CO2 for photosynthesis and facilitates oxygen exchange. It helps even out temperature fluctuations in the greenhouse and prevents high humidity.

The National Greenhouse Manufacturer’s Association recommends precise sizing and positioning of air inlet openings along greenhouse sides to get the best performance out of your ventilation system when cooling your greenhouse.

2. Level-Up Your Environmental Control System

Outfitting or retrofitting your greenhouse(s) with an environmental controller offers the benefits of tighter, more even climate control and more efficient greenhouse cooling.

Features such as remote monitoring save you time. Predictive controls linked to weather stations can see the summer heat wave developing before you do and make the needed adjustments to your greenhouse cooling system and ventilation automatically.

Even if you decide to step up your environmental control to the next stage, for example, from a simple thermostat to a staged controller, you will still see tangible benefits from the efficiencies you gain.

3. Check Your Sensor Placement

Sensors missing their shields, located too high above the crop, or placed in areas where the sun beats down on them or water continuously blasts them can give your environmental controller a false sense of what your greenhouse environment is doing.

Keith Bemerer, our Commercial Inside Sales Coordinator, recommends installing traditional thermometers on greenhouse poles and comparing their readings to those of your controller for better insights about your greenhouse cooling.

Bemerer also suggests placing sensors halfway across the width measurement and halfway down the length measurement of your greenhouse to gauge average temperatures accurately for that zone.

4. Modernize for Efficiency

Do you have a few aging greenhouses on your property that aren’t equipped to handle today’s cooling loads, but you’re resorting to the band-aid repair approach to get by?

Retrofitting may be an option, but finding suitable parts for the retrofit can present a challenge, depending on your greenhouse type.

Some suppliers don’t stock older extrusions to retrofit greenhouses for active ventilation. In some cases, the structure itself may not support the required sizes for passive ventilation.

Aging greenhouses may become costly to maintain, much like an old car. Eventually, the expenses of upkeep outweigh the benefits. Investing in a new structure could make more economic sense long-term and offer you better cooling efficiency.

Greenhouse curtains pulled in a retail setting for greenhouse cooling.

5. Pull the Curtains

Curtain systems offer a cost-effective and efficient supplement to your greenhouse cooling systems, and they double as energy curtains for heat retention at night.

Pull them closed during the day to help you maintain consistent internal temperatures and shield plants from excessive sunlight.

Suppliers offer a variety of curtain options with different shading levels for just about any growing situation. Just remember that manufacturers now design new curtain systems for square tubing instead of the round tubing used in some older greenhouses.

Cold Springs A-frame, Vail greenhouse with evaporative fan-and-pad cooling.

6. Try Evaporative Greenhouse Cooling

In hot, dry climates, evaporative greenhouse cooling methods, such as fan-and-pad cooling and fog/mist cooling, prove very effective.

Pad-and-fan setups draw air in from outside the greenhouse and pass it through water-saturated pads. The water creates a cooling effect as it evaporates.

High-pressure fog/mist evaporative systems use atomization lines strategically placed throughout the greenhouse to distribute water vapor. The water vapor evaporates rapidly, resulting in quicker temperature reduction compared to pad-and-fan setups.

7. Maintain Your Greenhouse Cooling Equipment

A greenhouse cooling system is only as good as you maintain it, so make regular maintenance a priority.

The University of Florida Extension (IFAS) website includes a comprehensive list of maintenance tasks for ventilation systems and evaporative greenhouse evaporative coolers.

Don’t let the summer heat catch you off guard. Our experienced team can set you up with a high-quality greenhouse cooling system and offer tailored solutions for maximum cooling control and efficiency. Reach out today to beat the heat!

Contact us at [email protected].


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