Short answer: choose greenhouse insect netting from the pest and life stage that must be excluded, the manufacturer's measured aperture and airflow data, the greenhouse ventilation design, and the way every opening will be sealed. Mesh count alone cannot define performance. A finer screen may block a smaller pest, but it also adds resistance that can reduce natural or fan-driven airflow.
Define the exclusion target before asking for mesh
Start with the crop-protection plan. List the pest species, relevant life stage, local pressure, season and any insect-vectored diseases. The crop adviser should state which pests need physical exclusion and which will still require monitoring, sanitation or biological controls. A screen is one part of integrated pest management, not proof that a greenhouse will remain pest free.
Ask bidders for the opening dimensions, thread diameter, material, weave, porosity and test method. Two products sold under the same mesh count can have different aperture geometry and resistance. Require a sample and a traceable product data sheet. If the supplier claims a specific exclusion efficiency, request the test organism, air speed, sample condition and independent report.
| Buyer decision | Evidence to provide | Bidder return |
|---|---|---|
| Pest exclusion | Pest species, life stage and crop-protection plan | Aperture, weave, test basis and limitations |
| Ventilation | Weather, vent geometry, fan curves and design airflow | Clean and loaded resistance plus required screen area |
| Installation | Every vent, door, drain, cable and service penetration | Sections, seals, access and replacement method |
| Operation | Cleaning resources, alarms and maintenance interval | Inspection points, allowable resistance and spare panels |
Treat airflow resistance as a design input
Insect screens create a pressure loss that changes with material, area, air speed and contamination. For fan ventilation, place the selected screen resistance on the fan curve together with shutters, pads, louvers and other system losses. A fan's free-air rating does not describe installed airflow. For natural ventilation, the designer must consider roof and side opening geometry, wind, temperature difference, screen resistance and crop blockage.
A finer product may need a larger installed area to keep pressure loss within the ventilation budget. That can require a framed screen box or a larger vent, not simply a piece of net fixed over the existing opening. Ask the ventilation designer to show clean-screen and loaded-screen cases. The commercial greenhouse ventilation guide covers fan curves, inlets and installed resistance.
Close the paths insects actually use
Draw each roof vent, side vent, fan opening, pad opening, doorway, drain, cable entry and material-transfer route. The netting detail must remain continuous at rails, corners and moving parts. Door strategy matters because workers, carts, plants and packaging can bypass a well-screened vent. If a vestibule or paired door is proposed, define its clear dimensions and how the doors are interlocked or managed.
Moving vents and roll-up sides need enough slack and support to travel without tearing, folding into mechanisms or opening edge gaps. Provide service access to clips, fasteners and motors. Check chemical compatibility with cleaners and crop-protection products. The commercial project planning guide shows where this interface belongs in the wider design and handover register.
Coordinate the net with climate control
The ventilation sequence should know when screened openings are available and whether a screen is becoming restricted. High temperature, high humidity, low wind, rain closure and fan failure need defined responses. If the selected net reduces natural ventilation beyond the crop limit, the project may need more opening area, mechanical ventilation, shade or another climate strategy.
Do not credit the net with yield, quality, pesticide or certification outcomes. Those results depend on pest pressure, monitoring, sanitation, crop practice and many other variables. Use the greenhouse automation guide to define monitoring, alarms and manual recovery around the installed system.
The greenhouse became hotter after screening: what should you check first?
Do not conclude from a temperature alarm alone that the mesh is too fine. Check whether the installed opening, equipment state or measurement conditions changed at the same time. Keep pest exclusion in place while the crop-protection adviser and ventilation specialist investigate.
UConn's insect-screening guide identifies screen resistance and maintenance as ventilation considerations. The University of Arizona's ventilation and screening guide explains why a fan's operating conditions matter. Neither supports diagnosing every hot greenhouse from mesh count alone.
Use this sequence to build a work order the maintenance team can act on.
| Check | Record | What the result can establish |
|---|---|---|
| Confirm the observation | Crop-zone and outside temperature, time, sensor position, weather and operating mode | Whether the comparison describes similar conditions |
| Check the opening | Actual vent travel, actuator state, folds, frame obstruction and blocked sections | Whether the available opening matches the intended arrangement |
| Check equipment state | Which fans, shutters, pads or vents are operating, and the controller command | Whether the expected ventilation mode is actually active |
| Inspect the screen | Product identity, deposits, damage, seals and cleaning history | Whether there is a specific maintenance or installation issue |
| Review measured airflow and pressure | Measurement locations, instruments, airflow and system configuration | Whether the designer can compare installed operation with the design basis |
A pressure reading is useful only with its measurement conditions. Screen pressure loss depends on airflow. Comparing readings at different flows can mislead; unchanged fan speed does not prove that airflow stayed constant. Ask the specialist to interpret the readings with the fan curve and the other installed restrictions. For a naturally ventilated house, wind and opening positions also matter.
If an actuator failed to open fully, record and correct that fault through the normal maintenance procedure, then check conditions again. If deposits are the identified issue, use the screen supplier's cleaning method and repeat the same observation. If the screen is clean and the installation matches the drawing, return the problem to the ventilation designer rather than repeatedly cleaning or selecting a different mesh by guesswork.
Write the result as a finding, action and repeat-check condition. For example: “Roof vent did not reach the commanded position; maintenance inspection requested; compare again after travel is restored under recorded weather.” This is an example of a record format, not a CFGET service case.
Keep the wider greenhouse ventilation design and control-system operating sequence beside the work order. The aim is to identify the next justified action without sacrificing pest control or purchasing equipment before the cause is understood.
Commission and maintain the installed system
Before handover, inspect continuity, tension, edge seals, doors and penetrations. Confirm that every vent completes its travel without rubbing or tearing the net. For a fan system, record airflow or static pressure at agreed points with clean screens. For natural ventilation, record opening positions, weather and representative inside conditions. Keep the instrument, test condition and acceptance limit with each result.
Dust, pollen and crop debris can increase resistance. Define how pressure, airflow or climate response will trigger cleaning rather than relying on a calendar alone. Cleaning must not enlarge apertures or damage UV protection. The maintenance plan should include safe access, repair materials, spare panels, inspection after storms and a record of replacements.
RFQ inputs for greenhouse insect netting
- Site, crop, production calendar and greenhouse dimensions
- Target pest species, life stage and disease-vector concern
- Required aperture, weave, porosity and independent test evidence
- Material, UV treatment, chemical compatibility and expected inspection basis
- Roof, side, fan, pad, door and service-opening geometry
- Weather data, design airflow, fan curves and allowable pressure budget
- Clean and loaded screen resistance plus required installed area
- Edge, corner, door, drain, cable and moving-vent details
- Cleaning access, trigger, repair method and spare-panel quantity
- Inspection, airflow or pressure tests, training and as-built records
Technical references
- University of Connecticut: insect screening as a pest-management tool
- University of Arizona CEAC: greenhouse ventilation and screening
- University of Connecticut: natural ventilation in greenhouses
Send the pest brief, vent schedule, fan data and maintenance plan through the CFGET contact page. Require each bidder to return the same screen and ventilation evidence.
Post time: Jul-01-2025
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