Winter increases pressure across a commercial greenhouse. Heating runs longer, ventilation changes, snow and ice add structural loads, and small gaps or equipment faults can become costly. Winterizing is not only about warmth; it is about reducing downtime, protecting crop quality, controlling energy use and ensuring the structure and environmental systems perform in harsh conditions.
Inspect the structure and envelope first
A thorough inspection before severe weather gives the team time to fix problems. The structure should be checked first. Winter wind, snow, ice and temperature swings can expose weaknesses not obvious in the growing season. Operators should walk inside and out for damaged or loose framing connections, doors, vents, glazing, poly coverings, seals and exterior parts.
Air and moisture entry points deserve particular attention. Damaged weather stripping, aging seals, loose panels and gaps around doors or vents can increase heat loss and make environmental control harder. For polyethylene-covered houses, the covering should be checked for punctures, tears, looseness or deterioration. Inflated double-poly systems should also be checked to confirm the inflation system is working.
Snow and wind requirements vary by location and greenhouse design. Structural components should be maintained 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 rather than waiting for the first major storm.
Service heating and controls
A heating problem in July may be inconvenient; a heating failure during a January cold snap can become an operational emergency. Before temperatures drop, the entire heating system should be inspected and any manufacturer-recommended service completed. Boilers, unit heaters, radiant systems, pumps, fans, thermostats, sensors and distribution equipment should all operate as intended.
Checklist items include heating equipment wear or operating issues; thermostats and environmental sensors; circulation and horizontal airflow fans; vents and louvers; control systems, alarms and backup systems; fuel supplies or delivery arrangements; and 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 problems, condensation and uneven growing conditions. The aim is to maintain the conditions the crop requires while operating the greenhouse as efficiently as practical.
Reduce heat loss and keep air moving
Heating is often one of the largest winter operating demands, so small efficiency problems are worth finding before the coldest weather. The building envelope should be inspected for areas where conditioned air may escape. 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 inspected too. Check material, drive system, cables, motors, sensors and controls before the system is needed nightly. Some growers add inflated polyethylene over polycarbonate or glass sidewalls and gable ends in fall for extra insulation. Where appropriate, this can reduce heat loss without permanently changing the glazing.
Equipment and storage should not interfere with airflow or heat distribution. A heating system may run correctly yet produce uneven temperatures if benches, stored materials, equipment or temporary barriers disrupt air movement. It is also a good time to review whether the greenhouse is still operated as designed. Production layouts, crops and benches change, and structures expand; environmental equipment may need adjustment as the business evolves.
Prepare for severe weather and snow
A 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 surrounding areas should be kept clear where practical so meltwater can drain. Doors and emergency exits should be checked for winter access.
Growers in snow-prone climates 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 on the roof or in the gutters. By heating where melting is needed, growers may keep energy curtains or blackout systems closed rather than opening them to let greenhouse heat reach the roof. This helps maintain the insulating layer while managing snow and ice.
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 design snow and wind conditions and have a response plan for unusual weather.