Winter puts added pressure on a commercial greenhouse. Heating systems run longer, ventilation changes, snow and ice increase structural loads, and small gaps or equipment problems can quickly become costly. Winterizing is not only about warmth; it is also about reducing downtime, protecting crop quality, controlling energy use and ensuring the structure and environmental systems perform in severe conditions. A thorough inspection before winter gives the team time to fix problems before they affect production.
Inspect the structure and envelope first
Inspect the structure first. Walk the greenhouse inside and out for damaged or loose framing connections, doors, vents, glazing, poly coverings, seals and exterior parts. Focus on 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-covered houses, check for punctures, tears, looseness or deterioration, and confirm that inflated double-poly systems are working. Snow and wind requirements vary by location and design, so maintain structural components according to the building’s intended design and local requirements. If condition or winter loading is a concern, involve the manufacturer or a qualified professional before the first major storm.
Prepare heating and environmental controls
Heating failures are inconvenient in summer but can become operational emergencies during a January cold snap. 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 visible wear or operating issues.
- Check thermostats and environmental sensors for proper operation.
- Test circulation and horizontal airflow fans.
- Confirm that vents and louvers open and close correctly.
- Inspect control systems, alarms and backup systems.
- Check fuel supplies or fuel delivery arrangements where applicable.
- Review generator or emergency power procedures.
Environmental controls need 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, condensation and uneven growing conditions. The goal is to meet crop needs while operating efficiently.
Close envelope gaps and protect airflow
Heating is often a large winter operating demand, so small efficiency problems are worth finding early. Inspect the envelope for escaping conditioned air. Doors that do not close properly, worn seals, gaps around penetrations, damaged glazing and poorly maintained vents make heating systems work harder. Where retractable energy curtains or thermal screens are installed, check 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 suited to the design and operation, this can reduce heat loss without permanently changing the glazing system.
Keep equipment and storage from interfering with airflow or heat distribution. A heating system may run correctly yet produce inconsistent temperatures if benches, materials, equipment or temporary barriers disrupt air movement. Review whether the greenhouse is still operated as designed; production layouts, crops, benches and structures change, and environmental equipment may need adjustment.
Plan for storms and snow removal
A winter plan should cover more than maintenance. The team should know what happens in severe weather. Assign responsibility for monitoring snow accumulation, heating equipment, alarms, backup power, vents and other critical systems during storms or extreme cold. Keep gutters, drainage paths and surrounding areas clear where practical so meltwater can drain. Inspect doors and emergency exits so winter weather does not block access.
In snow-prone climates, growers 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 in the gutters. Direct heat where melting is needed can allow energy curtains or blackout systems to stay closed rather than opening to let greenhouse heat reach the roof, helping maintain the insulating layer while managing accumulation.
Snow removal should follow recommendations for the specific greenhouse design. Improper removal can damage coverings or structural components, and unnecessary personnel activity on or around a snow-loaded greenhouse creates safety risks. Operators should understand the snow and wind conditions the structure was designed for and have a response plan for unusual weather.