Winter increases pressure on every part of a commercial greenhouse. Heating systems run longer, ventilation strategies must change, snow and ice add structural loads, and small gaps or equipment faults that were minor in warmer weather can turn into costly operating problems. A thorough pre-winter inspection gives growers time to correct those issues before they affect production, crop quality or energy use.
Inspect the structure and building envelope first
Operators should walk the greenhouse inside and outside, checking framing connections, doors, vents, glazing, poly coverings, seals and other exterior components for damage or looseness. The inspection should focus on places where air or moisture can enter. Worn weather stripping, aging seals, loose panels and gaps around doors or vents can increase heat loss and complicate environmental control.
For polyethylene-covered houses, the covering should be checked for punctures, tears, looseness and deterioration; inflated double-poly systems also need confirmation that inflation is working properly. Snow and wind requirements vary by location and greenhouse design, so structural components should be 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.
Service heating and environmental controls
A heating fault in summer is usually inconvenient; the same fault during a January cold snap can become an operational emergency. Before temperatures drop, the full heating system should be inspected and manufacturer-recommended service completed. 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 vents and louvers open and close correctly;
- inspecting control systems, alarms and backup systems;
- checking fuel supplies or delivery arrangements where applicable; and
- reviewing generator or emergency power procedures.
Environmental controls need particular attention because winter management is rarely only about heating. 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 the greenhouse as efficiently as practical.
Find heat losses and protect airflow
Because heating is often among the largest winter operating demands, the building envelope should be checked for conditioned air escaping through doors that do not close properly, worn seals, gaps around penetrations, damaged glazing and poorly maintained vents. Retractable energy curtains or thermal screens should also be inspected, including curtain material, drive systems, cables, motors, sensors and controls, so faults are corrected before nightly use.
Some growers add inflated polyethylene over polycarbonate or glass sidewalls and gable ends in the fall for extra insulation. Where suitable for the greenhouse 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; benches, stored materials, equipment or temporary barriers can disrupt air movement even when the heating system is operating correctly.
Winter planning should also cover severe-weather response. Teams need to know who monitors snow accumulation, heating equipment, alarms, backup power and vents during storms or extreme cold. Gutters, drainage paths and areas around the greenhouse should be kept clear where practical, and doors and emergency exits must remain accessible.
In snow-prone climates, growers may consider dedicated gutter snow-melt piping installed beneath 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 supplying heat where melting is needed, it may allow energy curtains or blackout systems to stay closed instead of being opened to let greenhouse heat reach the roof and gutters, helping maintain the insulating layer while managing snow and ice. Snow removal should always 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 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.