The biggest mistake in greenhouse insect netting is buying the finest mesh on the shelf “to be safe” — and discovering at the first heat wave that you have traded a pest problem for a climate problem: vents that move half the air, humidity that breeds botrytis, and a crop that sulk worse than it ever did with bugs. The right approach is the opposite: choose the coarsest aperture that still excludes your target pest, and engineer the screened area so the greenhouse keeps breathing. For the pests most greenhouse growers actually fight — butterflies, moths, beetles and other millimeter-scale insects — a knitted 2–7 mm insect net does that job while keeping airflow losses modest. Here is how to spec it.
Every aperture decision should begin with one question: what is the smallest insect you must stop? The 2–7 mm fine-mesh range maps cleanly onto the larger pest classes:
One honest boundary: sub-millimeter pests — whitefly, aphids, thrips — walk straight through any millimeter-scale net. Stopping them needs a different product class (fine anti-virus screens), and any supplier who sells you a 5 mm net “against whitefly” is selling you disappointment. If those are your primary pests, tell us — we will say so plainly and point you at the right spec.
Research on screened greenhouses is consistent: every insect screen cuts effective vent airflow, and finer screens cut it brutally — fine meshes can halve the ventilation rate, while coarse knits of the same coverage cost a fraction of that. Hot air trapped above the crop raises canopy temperature, humidity climbs at night, and fungal pressure replaces insect pressure. The engineering answer has two levers, and mesh fineness is only one of them:
This is why we knit insect net to custom widths up to 12 m: seamless oversized panels matched to your bay and vent dimensions, instead of narrow rolls sewn into a patchwork that leaks at every seam. Send the bay width and vent layout and we cut to it.
Roof and side vent screens are the standard commercial pattern — net only where air enters, fixed to aluminum profiles or clipped to the structure; pests are excluded at the entry points while the covering above stays glass or film. Full net houses (the whole structure clad in insect net) suit hot climates where maximum ventilation matters more than temperature control — a net house runs several degrees cooler than a film house at the same shading. Walk-in screened corridors at doors complete the system: most infestations enter on people and crates, not through vents. Whichever pattern, tension the net without over-stretching it — a knitted net pulled drum-tight opens its aperture and loses both pest exclusion and lifespan.
A net that keeps pests out keeps bees out too. On tomatoes and peppers (self-pollinating), that is free protection. On cucumbers, melons and zucchini, you must plan pollination deliberately: introduce bumblebee hives inside the netted house, or hand-pollinate, because the vents that no longer admit pests no longer admit bees either. Growers who learn this in week three of flowering learn it expensively — decide it at purchase time, and choose the aperture that still lets you manage the hive.
Greenhouse insect net works in the harshest UV position on the farm — stretched over sun-facing vents for years. Ours is knitted from 100% virgin HDPE with a per-batch UV-stabilizer dose, in 30–110 gsm (30–50 gsm for butterfly-weight draping, heavier for permanent tensioned screens), speced at 3–10 years depending on grade. Dust and pollen clog apertures over a season and quietly choke airflow; a yearly wash-down with low-pressure water restores it. Every container ships with factory retention samples, so a question in year three is answered against the actual material from your batch.
A 40’HQ carries 14–15 tons of netting — at the common 40–60 gsm greenhouse weights, roughly 230,000–350,000 m² per container. MOQ is 2 tons with mixed apertures and widths in one shipment; production runs 25–35 days after deposit; payment T/T 30/70 or 100% L/C at sight; samples are free, you cover the courier. Send your crop, pest list, bay width and destination port via the contact page or WhatsApp — we reply within 24 hours with an aperture recommendation, panel schedule and container loading.
Match the aperture to your smallest target pest: ~2 mm for small moths and leaf miners, 3–4 mm for butterflies and most moths (the commercial standard), 5–7 mm for beetles, stink bugs and bird/debris screening on roof vents. Always choose the coarsest aperture that still excludes the pest — every step finer costs ventilation.
Yes — every screen reduces vent airflow, and finer mesh reduces it more (fine meshes can halve ventilation rate). Compensate by choosing the coarsest working aperture and oversizing the screened area to 1.3–2× the vent opening, so total airflow through the net matches an open vent.
No — whitefly, aphids and thrips are sub-millimeter pests that pass through any millimeter-scale net. They require fine anti-virus screens, a different product class. Be wary of any supplier who claims a 5 mm net stops whitefly.
Self-pollinating crops (tomato, pepper) need nothing. Cucurbits (cucumber, melon, zucchini) need a plan: introduce bumblebee hives inside the netted house or hand-pollinate — the net excludes bees as effectively as pests.
3–10 years depending on grade and UV exposure, with a yearly low-pressure wash to clear dust and pollen from the apertures. The UV-stabilizer package decides the lifespan — we dose it per batch and keep retention samples at the factory.
Spec by pest, not by fear: the coarsest aperture that stops your insect, on an oversized screened area, in virgin HDPE with a documented UV package. Send your crop, pest list and bay width and we will spec the right greenhouse insect net — with panel sizes and loading in one reply.
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