Commercial greenhouse operators are being urged to complete a full winterization inspection before severe weather arrives, with the work framed not simply as keeping the house warm but as cutting downtime, protecting crop quality, controlling energy use and confirming that structures and environmental systems can handle less forgiving conditions.
Winter raises pressure across the operation: heating systems run longer, ventilation strategies shift, snow and ice add structural loads, and small gaps or equipment faults that seemed minor in warmer weather can turn into expensive problems.
Start with the structure
The structure should be inspected first, since winter wind, snow, ice and temperature swings expose weaknesses that are not obvious during the growing season. Growers should walk the greenhouse inside and out, checking framing connections, doors, vents, glazing systems, poly coverings, seals and other exterior components for damage or looseness.
Points where air or moisture can enter deserve particular attention. Damaged weather stripping, aging seals, loose panels and gaps around doors or vents increase heat loss and complicate environmental control. For polyethylene-covered houses, the covering should be checked for punctures, tears, looseness or deterioration, and inflated double-poly systems should be verified to be inflating correctly.
Snow and wind requirements vary by location and greenhouse design. Operators should confirm structural components are maintained according to the building's intended design and local requirements, and involve the manufacturer or a qualified professional if condition or winter loading is in doubt rather than waiting for the first major storm.
Heating and controls
A heating fault in July is an inconvenience; the same fault during a January cold snap becomes an operational emergency. Before temperatures drop, the entire system should be inspected and any manufacturer-recommended service completed, covering boilers, unit heaters, radiant systems, pumps, fans, thermostats, sensors and distribution equipment.
The suggested checklist includes:
- Inspecting heating equipment for visible wear or operating issues
- 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 or emergency power procedures
Environmental controls warrant close 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, so the aim is to hold the conditions the crop needs while running the greenhouse as efficiently as practical.
Envelope, screens and airflow
Because heating is often among the largest winter operating demands, small efficiency losses are worth finding early. 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 all make heating systems work harder.
Where retractable energy curtains or thermal screens are installed, the curtain material, drive system, cables, motors, sensors and controls should be inspected so faults are corrected before the system runs nightly. Some growers also add inflated polyethylene over polycarbonate or glass sidewalls and gable ends in autumn for an extra insulating layer; where suited to the design and operation, this can reduce heat loss without permanently changing the existing glazing.
Equipment and storage areas should also be kept from disrupting airflow or heat distribution. A heating system can operate correctly yet still produce inconsistent temperatures if benches, stored materials, equipment or temporary barriers block air movement. Winter is also a reasonable moment to check whether the greenhouse is still run as originally designed, since production layouts, crops, bench positions and structures change over time and environmental equipment may need adjustment.
Snow and storm response
A winter plan should go beyond routine maintenance. Teams should know who is responsible for monitoring snow accumulation, heating equipment, alarms, backup power and vents during storms or extreme cold. Gutters, drainage paths and the areas around the greenhouse should be kept clear where practical so melting snow and ice drain properly, and doors and emergency exits should be checked so winter weather cannot block access.
Growers in snow-prone climates may consider dedicated gutter snow-melt piping installed beneath the gutters. Operating 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, which can allow energy curtains or blackout systems to stay closed instead of being opened to let greenhouse heat reach the roof, helping maintain the insulating layer while managing accumulation.
Snow removal should always 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 creates safety risks. Operators should understand the snow and wind conditions their structure was designed for and have a response plan for unusual weather.