By Mark Wu, Co-founder & Technical Director, Sichuan Zhifang Net Industry Co., Ltd.
Almost every enquiry we get starts the same way. A grower wants shade net for a vegetable plot or a small greenhouse, and asks for the highest shade rate we make. The reasoning feels solid: if shade protects plants from heat, more shade should protect them better.
It does not work that way, and the mistake is expensive in both directions.
Put 90% net over a tomato crop and you have built a dark room. The plant stretches for light it cannot find, stems go thin, fruit set drops, and yield falls below what an unshaded crop would have given you. Put a 30% net over a lettuce house in a place with 45 °C afternoons and you have done almost nothing — the leaves still scorch.
The shade rate is not a quality score. It is a setting, and the right setting depends on the crop underneath it.
Shade rate is the fraction of incoming light the net blocks. Different crops evolved under different light loads, and each one has a range where it performs best.
| Crop | Working shade rate | What happens outside the range |
|---|---|---|
| Tomato, pepper, cucumber | 30–40% | Too little: blossom drop and sunscald. Too much: leggy growth, poor fruit set |
| Leafy greens, lettuce, spinach, herbs | 50–60% | Too little: bolting and leaf scorch. Too much: slow, soft growth |
| Orchids, ferns, shade ornamentals | 70–90% | These are the crops that genuinely need heavy shade |
| Nursery seedlings after transplant | 40–50% for the first weeks | Full sun right after transplant stalls establishment |
| Poultry houses, livestock shade | 50–70% | Chosen for animal comfort and airflow, not photosynthesis |
There is no single right number for a farm. If you grow more than one crop, the honest answer is either separate houses for separate crops or a rate that suits your main crop and accepts a compromise elsewhere.
Black net remains the workhorse for vegetables, orchards and livestock shade, and the standard grades sit in our black shade net range.
Two nets can both be labelled "70%" and behave nothing alike. Here is what sits behind the number.
One: the weight. Shade rate says how much light is blocked. Weight says how much material is there. A light 70% net and a heavy one can have the same shading figure, and only one of them survives a wind season. We measure our shade cloth in grams per square metre and quote it alongside the shade rate, because a buyer who only knows the percentage is buying half a specification.
Two: the weave. Knitted shade net and plain-woven net fail in completely different ways. A tear in a plain-woven net runs along the warp thread and keeps going — one snag becomes a metre-long split. In a warp-knitted structure, the loops lock the tear at the point of damage and it stays there. If your site gets storms or if you have branches and equipment moving around, this is the difference between a repair and a replacement. You can see our warp-knitted shade cloth range here.
Three: the UV guarantee. Shade net does not fail because the polymer wears out. It fails because ultraviolet light breaks the stabilizer down and the fibre goes brittle. The relevant unit is kilolangleys (kly) — the accumulated UV dose the material is guaranteed to survive. A net with a stated guarantee of 500kly is a different product from one with no figure at all, even when the shade rate printed on the label is identical.
Add the shrinkage rate to that list. A net that shrinks in service pulls away from its fixings, opens gaps at the edges, and lets light through exactly where you were trying to block it.
Across our own HDPE shade net grades the guarantee is stated at 500kly with a 1% shrinkage figure, published per product rather than summarised in adjectives. You can check the figures in our 95% greenhouse shade net range.
In a closed greenhouse, and in humid climates especially, the inner face of any screen collects condensation overnight. Without an anti-drip treatment, that moisture forms as droplets and falls onto the crop. Water landing on leaves every night at the coldest hour is the ideal condition for downy mildew, powdery mildew and grey mould.
This is one specification worth more than it costs, and it is invisible on a quotation that only lists shade rate and price. Ask for it by name. Anti-drip treatment, inner face, and ask what the supplier does if you do not.
None of this needs a lab. It needs four questions, and a supplier who can answer them.
Ask for the shade rate and the weight in g/m². If only one is offered, that is your answer about how they work.
Ask whether the fabric is knitted or plain woven, and what happens to a tear.
Ask for the UV guarantee in kly. Not "UV treated" — the number.
Ask whether anti-drip treatment is available.
A supplier with a real specification answers all four in one email. One who sends back a price and a photo has told you something useful too.
A short inspection at goods-in saves a season of arguing.
Open a roll and check the edge. A clean, straight, heat-set edge means the material was finished properly. A fraying edge with loose threads means shortcuts were taken somewhere you cannot see.
Measure a two-metre length against the stated width. Width tolerance tells you whether the roll was dimensionally controlled.
Then look for the anti-counterfeit mark. Every roll we ship carries a ZF label inside the packaging, and growers who reorder after five years still recognise it. It is not decoration. In this industry, plain net gets bought and re-labelled by traders who never made it, and a mark that the actual factory put there is the only reliable way to know what you are holding.
We have been manufacturing agricultural netting from Ziyang, Sichuan since 2011, from a workshop of nearly 10,000 m² with more than 50 sets of production equipment and an annual capacity of 20 million square metres. Our screens are made from new imported and domestic raw materials with UV and anti-ageing formulas built in, which is why we can state a 500kly guarantee and a 1% shrinkage rate rather than describing the product in adjectives.
The useful first step is not a price. Send us your crop list, your local summer UV conditions, and the area you need to cover. Our technical team will come back with a shade rate recommendation per crop, the weight and weave that suit your wind load, and a specification you can put beside any other quotation you hold.
Mark Wu, Co-founder & Technical Director
Sichuan Zhifang Net Industry Co., Ltd. — Sichuan, China
sales6@cnshadenet.com ｜ +86 177 8077 1810 (WhatsApp)
