Winter increases pressure on every part of a commercial greenhouse. Heating systems run longer, ventilation strategies change, snow and ice add structural loads, and small gaps or equipment faults that seemed minor in milder weather can become costly problems. Winterizing is not only about keeping the greenhouse warm; it is also a way to reduce downtime, protect crop quality, control energy use and help structures and environmental systems perform in harsher conditions.
A thorough inspection before severe weather gives the team time to correct problems before they affect production. The structure should be checked first, because winter wind, snow, ice and temperature swings can expose weaknesses hidden during the growing season.
Inspect the structure and envelope
Walk the greenhouse inside and out for damaged or loose components. Check framing connections, doors, vents, glazing, poly coverings, seals and exterior parts for wear. Snow and wind requirements vary by location and design, so operators should understand how climate-adaptive design affects structural performance in their region.
Pay attention to places where air or moisture can enter. Damaged weather stripping, aging seals, loose panels and gaps around doors or vents increase heat loss and complicate environmental control. For polyethylene houses, inspect coverings for punctures, tears, looseness or deterioration, and confirm that inflated double-poly systems are working.
Confirm that structural components are maintained according to the building’s intended design and local requirements. If structural condition or winter loading is a concern, involve the manufacturer or a qualified professional rather than waiting for the first major storm.
Test heating and environmental controls
A heating problem in July may be inconvenient, but a heating failure during a January cold snap can become an emergency. Before temperatures drop, inspect the entire heating system and complete manufacturer-recommended service. Boilers, unit heaters, radiant systems, pumps, fans, thermostats, sensors and distribution equipment should operate as intended.
- Inspect heating equipment for wear or operating issues.
- Check thermostats and environmental sensors.
- Test circulation and horizontal airflow fans.
- Confirm vents and louvers open and close correctly.
- Inspect controls, alarms and backup systems.
- Check fuel supplies or delivery arrangements where applicable.
- Review generator and emergency power procedures.
Environmental controls need particular attention because winter management is rarely about heating alone. Humidity, airflow, ventilation and temperature interact. Reducing ventilation too aggressively to conserve heat can create humidity problems, condensation and uneven growing conditions. The goal is to maintain crop conditions while operating efficiently.
Reduce heat loss and keep air moving
Heating is often one of the largest winter operating demands, so small efficiency problems are worth finding early. Inspect the building envelope for escaping conditioned air. Doors that do not close properly, worn seals, gaps around penetrations, damaged glazing and poorly maintained vents can make heating systems work harder.
Where retractable energy curtains or thermal screens are installed, check the material, drive system, cables, motors, sensors and controls before the system is needed every night. Some growers add inflated polyethylene over polycarbonate or glass sidewalls and gable ends in the fall for extra insulation. Where appropriate, this seasonal approach can reduce heat loss without permanently changing the glazing.
Keep equipment and storage areas from interfering with airflow or heat distribution. A heating system may run correctly yet produce inconsistent temperatures if benches, stored materials or temporary barriers disrupt air movement. Review whether the greenhouse is still operated as originally designed; production layouts, crops and benches change, and structures are expanded, so environmental equipment may need adjustment.
Plan for severe weather
A commercial winter plan should go beyond routine maintenance. The team should know who monitors snow accumulation, heating equipment, alarms, backup power, vents and other critical systems during storms or extreme cold. Where practical, keep gutters, drainage paths and surrounding areas clear so melting snow and ice can drain. Inspect doors and emergency exits to ensure winter weather will not prevent access.
Growers in snow-prone climates may consider dedicated gutter snow-melt piping beneath the gutters. Such a system can operate as its own heating zone and be activated only when snow or ice is present on the roof or in the gutters. By heating directly where melting is needed, growers may keep energy curtains or blackout systems closed rather than opening them to let greenhouse heat reach the roof, helping maintain the insulating layer while managing accumulation.
Snow removal should follow the recommendations for the specific greenhouse design. Improper removal can damage coverings or structural components, and unnecessary activity on or around a snow-loaded greenhouse can create safety risks. Operators should understand the snow and wind conditions their greenhouse was designed to handle and have a response plan for unusual weather.