Winter puts sustained pressure on every part of a commercial greenhouse. Heating systems run longer, ventilation strategies change, and snow and ice add structural loads. Small gaps or equipment faults that seem minor in milder weather can become costly operating problems when temperatures fall.
Winterizing should extend beyond keeping the greenhouse warm. It is meant to reduce downtime, protect crop quality, control energy use and confirm that structures and environmental systems can perform under harsher conditions. A thorough inspection before severe weather gives growers time to fix problems before they affect production.
Inspect the structure and envelope
The structure should be inspected first. Winter wind, snow, ice and temperature swings can expose weaknesses that are not obvious during the growing season. Walk the greenhouse inside and out for damaged or loose components. Check framing connections, doors, vents, glazing, polyethylene coverings, seals and other exterior parts for wear.
Air and moisture entry points deserve close attention. Damaged weather stripping, aging seals, loose panels and gaps around doors or vents can increase heat loss and complicate environmental control. For polyethylene houses, check for punctures, tears, looseness and deterioration. Inflated double-poly systems should be checked to confirm the inflation system works properly.
Snow and wind requirements vary by location and 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, involve the manufacturer or a qualified professional rather than waiting for the first major storm.
Service heating and controls
A July heating problem may be an inconvenience; the same problem in a January cold snap can become an operational 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 all operate as intended.
The checklist should include heating equipment checks; thermostat and environmental sensor checks; circulation and horizontal airflow fan tests; confirmation that vents and louvers open and close correctly; inspection of controls, alarms and backups; fuel supply or delivery checks where applicable; and review of generator or 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 aim is to maintain crop requirements while operating efficiently.
Reduce heat loss and protect airflow
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 nightly use. Some growers add inflated polyethylene over polycarbonate or glass sidewalls and gable ends in fall for extra insulation. Where appropriate, this seasonal step can reduce heat loss without permanently changing the glazing system.
Equipment and storage should not interfere with airflow or heat distribution. A heating system may run correctly yet produce inconsistent temperatures if benches, stored materials, equipment or temporary barriers disrupt air movement. This is also a good time to review whether the greenhouse is still operated as originally designed, because layouts, crops, benches and structures change.
Plan for snow, drainage and emergencies
A commercial winter plan should go beyond maintenance. The team should know what happens in severe weather and who monitors snow accumulation, heating equipment, alarms, backup power, vents and other critical systems during storms or extreme cold.
Keep gutters, drainage paths and areas around the greenhouse clear where practical so melting snow and ice can drain. Inspect doors and emergency exits so winter weather does not block access. Growers in snow-prone climates may consider dedicated gutter snow-melt piping beneath the gutters. It can operate as its own heating zone and be activated only when snow or ice is present on the roof or gutters. By supplying heat where melting is needed, growers may be able to keep energy curtains or blackout systems closed instead of opening them to let greenhouse heat reach the roof and gutters, helping maintain the insulating layer while managing snow and ice.
Snow removal should follow recommendations for the specific greenhouse design. Improper removal can damage coverings or structural components, while unnecessary personnel activity on or around a snow-loaded greenhouse creates safety risks. Operators should understand the snow and wind conditions their greenhouse was designed to handle and have a response plan for unusual weather.