Winter places heavier demands on every part of a commercial greenhouse. Heating systems run for longer, ventilation strategies have to change, snow and ice add load to the structure, and small gaps or equipment faults that caused little trouble in warmer weather can turn into expensive problems once temperatures fall.
For commercial growers, the task is broader than keeping the house warm. A structured winterization programme is aimed at reducing downtime, protecting crop quality, controlling energy use and confirming that the structure and environmental systems can perform when outside conditions become less forgiving. Inspecting thoroughly before severe weather arrives gives a team time to fix problems before they affect production.
Structure and envelope
The structure should be among the first areas checked, because winter wind, snow, ice and temperature swings expose weaknesses that stay hidden during the growing season. Walking the greenhouse inside and out to look for damaged or loose components — framing connections, doors, vents, glazing systems, poly coverings and seals — is the starting point.
Points where air or moisture can enter deserve particular attention. Damaged weather stripping, ageing seals, loose panels and gaps around doors or vents all raise heat loss and make environmental control harder. Polyethylene-covered houses should be checked for punctures, tears, looseness and deterioration, and inflated double-poly systems should be confirmed to be inflating correctly.
Snow and wind requirements vary by location and greenhouse design, so operators should confirm that structural components are maintained according to the building's intended design and local requirements. Where structural condition or winter loading is in doubt, the guidance is to involve the manufacturer or a qualified professional rather than wait for the first major storm.
Heating and environmental control
A heating fault in July is an inconvenience; the same fault during a January cold snap becomes an operational emergency. The full heating system — boilers, unit heaters, radiant systems, pumps, fans, thermostats, sensors and distribution equipment — should be inspected and serviced as the manufacturer recommends before temperatures drop. The checklist covers:
- 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;
- reviewing generator and emergency power procedures.
Environmental controls need separate attention because winter management is rarely about heating alone: humidity, airflow, ventilation and temperature interact. Cutting ventilation aggressively to conserve heat can produce humidity problems, condensation and uneven growing conditions, so the aim is to hold the conditions the crop requires while running the house as efficiently as practical.
Energy, airflow and snow response
Because heating is often one of the largest winter operating demands, small efficiency losses are worth finding early. Doors that do not close properly, worn seals, gaps around penetrations, damaged glazing and poorly maintained vents all make heating systems work harder. Retractable energy curtains or thermal screens should have their material, drive system, cables, motors, sensors and controls checked so faults are corrected before the system is needed every night. Some growers also add inflated polyethylene over polycarbonate or glass sidewalls and gable ends in autumn for an extra insulating layer where the design allows.
Storage and equipment placement matters too: a heating system can run correctly and still produce uneven temperatures if benches, stored materials, equipment or temporary barriers disrupt air movement. Winter is also a reasonable moment to check whether the greenhouse is still operated the way it was designed, since production layouts, crops, benches and structures change over time.
A winter plan should extend beyond maintenance. Teams should know who monitors snow accumulation, heating equipment, alarms, backup power and vents during storms or extreme cold. Gutters, drainage paths and the areas around the house should be kept clear so meltwater drains, and doors and emergency exits checked so winter weather does not block access.
Growers in snow-prone climates may consider dedicated gutter snow-melt piping installed beneath the gutters. Running as its own heating zone and activated only when snow or ice is present on the roof or in the gutters, it supplies heat where melting is needed and can allow energy curtains or blackout systems to stay closed instead of being opened to let greenhouse heat reach the roof, helping keep the insulating layer in place. Snow removal should always follow the recommendations for the specific greenhouse design, because improper removal can damage coverings or structural components, and unnecessary personnel activity on a snow-loaded structure creates safety risks. Operators are advised to know the snow and wind conditions their greenhouse was built for and to have a response plan for unusual weather.