Winter increases pressure on the structure, heating, ventilation and crop environment of a commercial greenhouse. A pre-season inspection gives growers time to correct problems before snow, ice, wind and low temperatures affect production. The aim is not only to keep the greenhouse warm, but also to reduce downtime, protect crop quality, control energy use and keep environmental systems performing under harder conditions.
Inspect the structure and envelope first
Walk the greenhouse inside and out, checking framing connections, doors, vents, glazing, polyethylene coverings, seals and exterior components for damage or looseness. Pay particular attention to places where air or moisture can enter. Worn weather stripping, aging seals, loose panels and gaps around doors or vents increase heat loss and complicate environmental control.
For polyethylene-covered houses, look for punctures, tears, looseness or deterioration, and confirm that inflated double-poly systems are working properly. Snow and wind requirements vary by location and greenhouse design, so components should be 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 before a major storm.
Prepare heating and controls for cold snaps
A heating fault in July may be an inconvenience; one during a January cold snap can become an operational emergency. Before temperatures fall, inspect the full 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:
- Inspecting heating equipment for visible wear or operating issues
- 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 need similar attention because winter management is rarely about heating alone. Humidity, airflow, ventilation and temperature interact. Cutting ventilation too aggressively to save heat can create humidity problems, condensation and uneven growing conditions. The goal is to meet crop requirements while running the greenhouse as efficiently as practical.
Find heat losses before the coldest weather
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, including doors that do not close properly, worn seals, gaps around penetrations, damaged glazing and poorly maintained vents. 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 fall for an extra insulating layer. Where suitable for the design and operation, this seasonal measure can reduce heat loss without permanently changing the glazing. Equipment and storage areas should also be kept from disrupting airflow or heat distribution; a heating system can run correctly yet produce uneven temperatures if benches, materials, equipment or temporary barriers block air movement.
The pre-winter review is also a useful time to review whether the greenhouse is still operated as originally designed. Production layouts, crops and benches change, structures are expanded, and environmental equipment that suited the original operation may need adjustment.
Assign storm duties and plan for snow
A winter plan should cover severe weather, not just 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 the area around the greenhouse clear so melting snow and ice can drain, and make sure doors and emergency exits remain accessible.
In snow-prone climates, growers may consider dedicated gutter snow-melt piping beneath the gutters. Operated as a separate heating zone, it can be activated when snow or ice is present on the roof or in the gutters. By supplying heat where melting is needed, this 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 accumulation.
Snow removal should follow the 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.