Hail net is judged by two numbers — its GSM, the weight per square metre, and its mesh aperture, the size of the holes. Get either wrong and a heavy storm tears through the net or the hail slips through the gaps. Here is how to match both to your risk.
People buy anti-hail netting as if it were one product, but it is really a family — light net for light hail, heavy net for hail belts, and a range of mesh sizes in between. The spec you choose decides whether the net catches the hail or just decorates the orchard while the crop gets beaten. Here is how to read the two numbers that matter.
GSM is grammes per square metre, the direct measure of how much HDPE is in the net and therefore how much impact it will take. 40–60 gsm is a light net for regions with occasional, small hail. 60–90 gsm is the standard orchard range — enough for a real storm without overloading the support structure. 90–120 gsm is the heavy end for established hail belts, where a net has to take repeated hard hits. The trade-off is wind load: a heavier net catches more wind, so the posts and cables have to be sized to match. Heavier is not automatically better; it has to match your storm risk.
The mesh aperture is the size of the hole, and it decides two things at once: whether hailstones pass through, and how much light the crop still gets. 6–8 mm is an open mesh for light-hail regions — fine stones mostly bounce, and a lot of light comes through. 4–6 mm is the standard orchard aperture, small enough to stop most hail while letting bees and air through. 3–4 mm is a fine net for severe hail, but it also shades the crop more, so it is reserved for the places that genuinely need it. A hail net also keeps birds off, so the mesh doubles as bird protection.
| Hail risk | GSM | Mesh aperture | Notes |
|---|---|---|---|
| Light | 40–60 | 6–8 mm | Occasional small hail, more light through |
| Moderate | 60–90 | 4–6 mm | Standard orchard spec |
| Severe | 90–120 | 3–4 mm | Hail belts, repeated hard storms |
Hail net comes in white, black and a light transparent green, and the colour is not just cosmetic. White and transparent nets let through more light and are standard over fruit and vines; black nets run warmer and are used where a little shading is welcome. Whatever the colour, demand UV-stabilized HDPE — a hail net sits in full sun for years, and without the stabilizer it embrittles and shatters on the first real storm it should have survived. A stabilized net is a 5–8 season asset, not a one-season gamble.
The spec on the net is only half the job — the structure it sits on is the other. Hail net is normally run over the orchard on posts and support cables, tensioned so the net has some give to absorb a strike rather than tear at a fixing. Our anti-hail netting for orchards guide covers how to size and support the net over trees and vines. For the net itself, buy it slightly larger than the area so it can be tensioned and fixed to the cables with reinforced selvedge, and check with your supplier that the GSM you are quoted is the GSM you will receive. If you would like the spec matched to your region's storm record, tell us where you grow and we will recommend the GSM, mesh and colour to go with it.
40–60 gsm for light, occasional hail; 60–90 gsm for standard orchard protection; 90–120 gsm for severe hail belts. Match the weight to your storm risk, not to the cheapest quote.
4–6 mm is the standard orchard aperture for most regions. 6–8 mm is fine where hail is small and light; 3–4 mm for severe hail, at the cost of more shade.
A little. The finer the mesh, the more light it blocks, so white or transparent net is used over fruit and vines to let more light through. A 4–6 mm white net keeps most light while stopping hail.
A UV-stabilized HDPE hail net typically serves 5–8 seasons. The stabilizer is what matters — without it the net embrittles in the sun and fails on the first storm it should have survived.
Match GSM to storm severity and mesh to hail size — 60–90 gsm with a 4–6 mm aperture is the standard orchard spec for most regions. Tell us where you grow and we will spec it precisely.
Related Products