Winter places greater strain on every part of a commercial greenhouse. Heating systems run longer, ventilation strategies shift, snow and ice add structural loads, and small gaps or equipment faults that were minor in warmer weather can become costly operational problems. A thorough inspection before severe conditions arrive gives growers time to correct issues before they affect production.
Winterizing is not only about keeping the house warm. The checklist frames it as a way to reduce downtime, protect crop quality, control energy use and confirm that structures and environmental systems can perform under less forgiving conditions.
Start with the structure and envelope
Operators should walk the greenhouse inside and out, looking for damaged or loose framing connections, doors, vents, glazing, poly coverings, seals and other exterior components. Areas where air or moisture can enter deserve particular attention: worn weather stripping, aging seals, loose panels and gaps around doors or vents can increase heat loss and complicate environmental control.
- Inspect polyethylene coverings for punctures, tears, looseness or deterioration.
- Confirm that inflated double-poly systems are inflating properly.
- Check that structural maintenance matches the building’s intended design and local snow and wind requirements.
- Involve the manufacturer or a qualified professional if structural condition or winter loading is uncertain.
Test heating and environmental controls
A heating failure in mild weather may be inconvenient; a failure during a January cold snap can become an emergency. Before temperatures fall, the entire heating system should be inspected and manufacturer-recommended service completed. Boilers, unit heaters, radiant systems, pumps, fans, thermostats, sensors and distribution equipment should operate as intended.
- Check heating equipment for visible wear or operating problems.
- Verify thermostats and environmental sensors.
- Test circulation and horizontal airflow fans.
- Confirm that vents and louvers open and close correctly.
- Inspect controls, alarms and backup systems.
- Review fuel supply or delivery arrangements where applicable.
- Review generator or emergency-power procedures.
Environmental control needs attention because winter management is rarely about heating alone. 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 operating efficiently.
Find heat losses and protect airflow
The building envelope should be checked 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. Retractable energy curtains or thermal screens should be inspected, including material, drive system, 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 autumn for extra insulation. Where suitable for the design and operation, this seasonal layer can reduce heat loss without permanently changing the glazing. Equipment, stored materials, benches or temporary barriers should not disrupt airflow or heat distribution; a heating system can operate correctly yet produce uneven temperatures if air movement is blocked.
Winter planning should also consider whether the greenhouse is still operated as originally designed. 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 go beyond 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. 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.
Growers in snow-prone regions may consider dedicated gutter snow-melt piping beneath gutters. Such a system can operate as its own heating zone and be activated only when snow or ice is present, supplying heat where melting is needed. This may allow energy curtains or blackout systems to remain closed instead of opening them to let greenhouse heat reach the roof and gutters, helping preserve the insulating layer while managing accumulation.
Snow removal should follow recommendations for the specific greenhouse design. Improper removal can damage coverings or structure, and unnecessary activity on or around a snow-loaded greenhouse can create safety risks. Operators should understand the snow and wind conditions the structure was designed for and have a response plan for unusual weather.