A productive greenhouse is not one net — it is three, each doing a different job in a different place. Shade cloth on the roof, insect mesh on the walls, and ventilation netting on the ends. Here is how to spec all three so they work together.
Growers usually buy greenhouse netting one product at a time — a shade cloth one year, insect mesh the next — and end up with a mismatched system. The cleaner way is to think of the greenhouse as three positions, each with one job: cut light on top, keep pests out on the sides, and let air move at the ends. Spec each one separately and they do more together than any single net could.
On the roof, shade cloth controls light and temperature. On the side walls, insect netting keeps pests out while air still passes. On the end walls and doors, a finer mesh or a windbreak net manages ventilation and drafts. Mix them up — put heavy shade on the walls, for example — and you block the very airflow your shade cloth is trying to create.
The roof cloth does the heavy lifting. Knitted HDPE shade net comes in 30–90% shade, and the right percentage depends on your crop and climate — leafy greens want more shade, fruiting crops less. For most greenhouses 50–70% is the working range; we cover the crop-by-crop choice in our shade net percentage guide. Match GSM to the job: 40–90 gsm for light shade, 100–180 gsm where the roof takes wind and structure load. In a hot region, a reflective aluminum shade net on the roof cools harder because it reflects heat instead of absorbing it.
The side walls are the greenhouse's skin, and their job is exclusion without suffocation. Insect-proof netting is specified by mesh count — the number of holes per inch — and the right mesh depends on the pest you are stopping. 17-mesh keeps out moths and larger pests, 25–40 mesh stops whitefly and thrips, and 50-mesh keeps out almost everything. The finer the mesh, the less air moves through, so only go as fine as your pest problem demands. Our full insect netting mesh size guide matches mesh to pest.
The end walls are where air enters and leaves, and here a windbreak net earns its place. A 50%-porosity windbreak lets air circulate while breaking the gusts that can whip young plants and stress the structure. Think of it as a throttle: it slows strong wind rather than stopping it, which is exactly what a greenhouse needs at the ends. On exposed sites, a windbreak a few metres upwind of the house also cuts the wind load on the whole structure.
| Position | Net | Typical spec | Job |
|---|---|---|---|
| Roof | Shade net (black or aluminet) | 30–60% shade, 40–120 gsm | Cut light and heat |
| Side walls | Insect net | 25–50 mesh, 60–80 gsm | Exclude pests, keep airflow |
| End walls / doors | Insect net + windbreak | 17–25 mesh / 50% porosity | Ventilation, break gusts |
Order the three nets at the same time and you get three advantages. First, the widths and eyelets match, so installation is one pass instead of three patch-ups. Second, one supplier means one spec — the GSM, mesh and shade percentages are designed to work as a set rather than fighting each other. Third, buying a full system usually drops the unit price and shipping per square metre. If you are unsure where to start, spec the roof first — it fixes the shade percentage — then choose the wall mesh to match your pest pressure, and finish with the end-wall ventilation. Tell us your crop, region and house size and we will put the three-part spec together for you.
A knitted HDPE shade net, 30–60% shade for most crops, laid over or under the roof glazing. In hot climates a reflective aluminum shade net cools more effectively.
Match the mesh to the pest: 17-mesh for moths and larger insects, 25–40 mesh for whitefly and thrips, and 50-mesh for near-total exclusion. Use the finest mesh your pest pressure actually needs, since finer mesh reduces airflow.
Not always, but exposed or large houses benefit from a 50%-porosity windbreak at the ends or upwind — it breaks gusts and protects young plants without blocking ventilation.
50–70% covers most protected crops. Leafy greens can take more shade, fruiting crops less. Climate matters too — hotter regions go higher. See our shade percentage guide for a crop-by-crop table.
Match the net to the position — shade on top, insect mesh on the sides, ventilation at the ends — and spec each one separately. Send us your house size and crop and we will build the three-part system for you.
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