Commercial greenhouse operators face a different set of pressures once winter arrives. Heating systems run longer, ventilation strategies must change, snow and ice add structural loads, and small gaps or equipment faults that caused little trouble in milder weather can become costly operating problems.
A thorough inspection before severe weather gives growers time to correct issues before they affect production. The goal is not only to keep the greenhouse warm, but also to reduce downtime, protect crop quality, control energy use and keep structures and environmental systems performing under harsher conditions.
Inspect the structure and envelope first
Winter wind, snow, ice and temperature swings can expose weak points that remain hidden during the growing season. Operators should walk the greenhouse inside and out, checking framing connections, doors, vents, glazing, polyethylene coverings, seals and other exterior components for damage or looseness.
Air and moisture entry deserve close attention. Damaged weather stripping, aging seals, loose panels and gaps around doors or vents increase heat loss and make environmental control harder. Poly-covered houses should be checked for punctures, tears, looseness and deterioration, and inflated double-poly systems should be tested to confirm the inflation system is working.
Snow and wind requirements vary by location and greenhouse design. Operators should 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, the greenhouse manufacturer or a qualified professional should be involved before the first major storm, not afterward.
Test heating and environmental controls
A heating problem in July may be an inconvenience; the same problem during a January cold snap can become an operational emergency. The entire heating system should be inspected and manufacturer-recommended service completed before temperatures fall. Boilers, unit heaters, radiant systems, pumps, fans, thermostats, sensors and distribution equipment should all operate as intended.
A winterization checklist should include:
- Inspecting heating equipment for visible wear or operating problems.
- Checking thermostats and environmental sensors.
- Testing circulation and horizontal airflow fans.
- Confirming that vents and louvers open and close correctly.
- Inspecting control systems, alarms and backup systems.
- Checking fuel supplies or delivery arrangements where applicable.
- Reviewing generator or emergency power procedures.
Environmental controls require 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 aim is to maintain the conditions the crop needs while operating the greenhouse as efficiently as practical.
Reduce heat loss and protect airflow
Heating is often one of the largest winter operating demands, so small efficiency problems are worth finding early. Operators should inspect the building envelope for escaping conditioned air, including doors that do not close properly, worn seals, gaps around penetrations, damaged glazing and poorly maintained vents.
Where installed, retractable energy curtains or thermal screens should be checked before they are needed every night. That means inspecting the curtain material, drive system, cables, motors, sensors and controls. Some growers also add inflated polyethylene over polycarbonate or glass sidewalls and gable ends in the fall for extra insulation. Where suitable for the design and operation, this seasonal layer can reduce heat loss without permanently changing the existing glazing.
Equipment and storage areas should not interfere with airflow or heat distribution. A heating system may be running correctly yet produce inconsistent temperatures if benches, stored materials, equipment or temporary barriers disrupt air movement. Winter preparation is also a good time to review whether the greenhouse is still operated as originally designed, since production layouts, crops, benches and structures change over time.
Plan for snow, drainage and emergencies
A winter plan should cover more than routine maintenance. The team should know what happens when severe weather arrives and who is responsible for monitoring snow accumulation, heating equipment, alarms, backup power, vents and other critical systems during storms or extreme cold. Gutters, drainage paths and areas around the greenhouse should be kept clear where practical so melting snow and ice can drain, and doors and emergency exits should remain accessible.
Growers in snow-prone climates may consider dedicated gutter snow-melt piping installed beneath the gutters. Such a system can operate as its own heating zone and be activated when snow or ice is present on the roof or in the gutters. By supplying heat where melting is needed, it may allow energy curtains or blackout systems to remain closed instead of being opened to let greenhouse heat reach the roof and gutters, helping maintain the insulating layer while managing accumulation.
Snow removal should always follow 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 the structure was designed to handle and have a response plan for unusual weather.