Commercial greenhouses face added pressure in winter: heating systems run longer, ventilation settings shift, snow and ice increase structural loads, and small gaps or equipment faults can turn costly. A thorough pre-winter inspection gives growers time to fix problems before they affect production, crop quality or energy use.
Start with the structure and envelope
Operators should walk the greenhouse inside and out, checking framing connections, doors, vents, glazing, poly coverings, seals and exterior components for damage or looseness. Areas where air or moisture can enter deserve attention: worn weather stripping, aging seals, loose panels and gaps around doors or vents can raise heat loss and complicate environmental control.
Polyethylene-covered houses should be checked for punctures, tears, looseness and deterioration. Inflated double-poly systems also need confirmation that the inflation equipment is working. 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 a major storm.
Service heating and controls
A heating failure in July may be inconvenient; one during a January cold snap can become an operational emergency. Before temperatures fall, growers should 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.
A winter checklist should cover visible wear or operating issues in heating equipment; thermostat and environmental sensor operation; circulation and horizontal airflow fans; correct opening and closing of vents and louvers; control systems, alarms and backups; fuel supplies or delivery arrangements; and generator or emergency power procedures.
Balance ventilation, humidity and airflow
Winter management is rarely only about heating. Humidity, airflow, ventilation and temperature interact. Reducing ventilation too aggressively to save heat can create humidity problems, condensation and uneven growing conditions. The aim is to meet crop requirements while running the greenhouse as efficiently as practical.
Heating is often a major winter operating demand, so envelope leaks are worth finding early. Doors that do not close properly, worn seals, gaps around penetrations, damaged glazing and poorly maintained vents can all make heating systems work harder. Where installed, retractable energy curtains or thermal screens should be checked along with their material, drive system, cables, motors, sensors and controls.
Some growers add inflated polyethylene over polycarbonate or glass sidewalls and gable ends in 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 also be kept from disrupting airflow or heat distribution, because benches, materials, equipment or temporary barriers can produce inconsistent temperatures even when the heating system is running correctly.
The pre-winter review is also a chance to compare current use with the original design. Production layouts, crops, benches and structures change, and environmental equipment that suited the original operation may need adjustment.
Prepare for snow, ice and emergencies
A commercial winter plan should assign responsibility for monitoring 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 so melting snow and ice can drain, and doors and emergency exits should remain accessible.
In snow-prone climates, dedicated gutter snow-melt piping installed beneath gutters can operate as its own heating zone and be activated only when snow or ice is present. By supplying heat where melting is needed, this approach can 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 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 know the snow and wind conditions the structure was designed to handle and have a response plan for unusual weather.