A gardener nets a plum tree the week the first flowers open, because the pigeons found it last year and he is not losing the crop twice. The net goes on tight and neat. Six weeks later the tree holds almost no fruit, and the pigeons never touched it. Nothing crossed the mesh that spring, including the bees.
That mistake repeats in gardens every season, and it has nothing to do with the quality of the netting. It comes from treating a barrier as a single job. Netting is a filter, and a filter has a hole size. Set the hole size for the pest and you may also shut out the insects that make the crop.
This guide works through the numbers, the timing and the layout choices that let a garden keep its pollinators while it keeps everything else out.
Executive Summary
Garden netting that lets pollinators in is built around one number: aperture. Honey bees pass a 6 mm to 7 mm mesh, bumblebees need roughly 10 mm, and anything below 2 mm excludes insects almost completely. Pests have their own thresholds, so the aperture that stops a cabbage white is not the one that stops a carrot fly.
The second decision is timing. Most fruiting crops need insects only during flowering, which lasts two to three weeks. Net after petal fall and the pollination question disappears. Where the cage has to stay closed, part-netting and hand pollination cover the gap.
Tell Us the Crop and the Pest, Get an Aperture
Send the crop, the pest you are fighting and whether the plants need insect pollination. We return aperture, wire diameter, panel sizes and a fixing layout, with a cut-to-size quote and a lead time.
Request a Mesh SpecQuick Answer
Garden netting that lets pollinators in uses an aperture wider than the insect you want to keep, usually 10 mm or more for bumblebees and 6 mm to 7 mm for honey bees. Net flowering crops only after petal fall, or leave the flowering rows uncovered, and save fine mesh for crops that never need insect pollination.
Key Takeaways
- Aperture is a filter setting, not a strength rating, and it decides which insects reach the flowers.
- Bumblebees need about 10 mm of clearance; honey bees manage 6 mm to 7 mm.
- Fruit crops need insects for two or three weeks, then need nothing but exclusion.
- Fine mesh below 2 mm excludes pests and pollinators together, so reserve it for seedbeds.
- Part-netting a garden usually beats one cage over the whole plot.
Why Most Garden Netting Shuts Out the Wrong Insects
Netting sold for bird control is sized for birds. A 25 mm mesh stops a pigeon and reads as a light, open barrier, which is exactly right for a fruit cage. The same mesh also passes cabbage white butterflies without slowing them, so a gardener who buys it for brassicas gets the birds under control and caterpillars anyway.
Netting sold as insect mesh swings the other way. A 1 mm or 2 mm weave stops almost everything with wings, including the pollinators the crop needs. Hoverfly and solitary bee passage stops at that size, and the bed sets almost no fruit. It works well on a seedbed and badly on a bean row.
The useful range sits between those two products, and it is narrow. A mesh aperture for honey bees and one for cabbage white sit two bands apart, and a handful of millimeters decides whether a bed is pollinated or stripped. Most gardeners never see that range, because the market sells either bird netting or insect mesh.
The garden netting range built around crop protection covers that middle ground. Choosing a point inside it is the rest of this guide.
The Aperture Numbers That Decide Who Gets Through
Aperture size is the only thing that matters here. Body width, not wingspan, sets the limit, because a butterfly folds its wings but cannot fold its thorax.
| Aperture | Pollinators that pass | Pests it stops | Typical garden use |
|---|---|---|---|
| 20 to 25 mm | Bumblebees, honey bees, hoverflies, most solitary bees | Pigeons, crows, deer, rabbits | Fruit cages and tall garden cages |
| 10 to 12 mm | Honey bees, hoverflies, small solitary bees, most bumblebee workers | Small birds, cabbage white adults | Beans, soft fruit, mixed beds |
| 6 to 7 mm | Honey bees at a squeeze, small solitary bees; bumblebees blocked | Cabbage white, most moths, larger beetles | Brassicas, salad beds |
| 1 to 2 mm | None in practice | Carrot fly, flea beetle, aphids, whitefly | Seedbeds and seedling protection |
The table is a starting point. The guide to choosing a garden mesh walks the same range with panel sizes attached.
Mesh aperture for honey bees
Mesh aperture for honey bees needs about 6 mm to 7 mm of clearance. A worker measures roughly 4 mm across the thorax, but it needs room to work through without shedding pollen or tangling a wing, so the practical figure sits above the body size.
That is why a 7 mm brassica mesh still crops well. Honey bees and small solitary bees get in, and cabbage white adults do not. The trade-off is bumblebees, which stay outside.
Hoverflies and small solitary bees do a large share of pollination on early-flowering fruit, and most are small enough for 6 mm. A tight mesh keeps more of the working population than the bumblebee figure suggests.
Bumblebee thorax width and netting
Bumblebee thorax width runs closer to 8 mm on a worker and more on a queen, and the body is bulky behind it. In practice a bumblebee needs 10 mm to 12 mm, which is why a cage built for butterflies also excludes the best pollinators of tomatoes, peppers and clover.
If bumblebees are the main pollinators on the plot, the aperture decision moves up a band. Field guidance from the Xerces Society on pollinator conservation treats access to flowering plants as the first constraint on any pollinator plan, and a cage that seals the flowers fails at step one.
Net the Crop, Not the Whole Garden
One cage over the whole plot is the layout most gardeners picture, and it is usually the wrong one. A single barrier forces a single aperture, and one aperture cannot serve crops with opposite needs. Brassicas want small holes. Beans want wide ones.
To part-net a garden for pollinators, net only the crops that need exclusion and leave the flowering ones open. A brassica cage at 7 mm can sit beside an open bean row, and neither compromises the other. Build the cages as separate crop covers sized to each bed rather than one envelope around the plot.
The same logic works in time rather than space. A fruit cage only has to be closed while the fruit is worth stealing. During blossom it can stay open, and it can go back on once the petals drop.
The pollination window before netting
The pollination window before netting is the two to three weeks a crop spends in flower. Apples, pears and plums need insects across that window, and one cold, wet week inside it can cost most of the crop.
Watch the flowers rather than the calendar. Netting a flowering cherry without blocking bees is possible at 20 mm, but the safer routine is to wait for petal fall. For cane fruit and strawberries the window is shorter and the crop is self-fertile, so the risk is lower, though the rule still holds.
Fine Mesh, Wide Mesh and What Each Costs
Fine mesh buys pest control and pays for it in pollination. Wide mesh buys airflow and pollinator access and pays for it in pest pressure. The choice follows the crop, not the gardener’s taste.
Cost per square meter moves with aperture, because a tighter weave uses more wire and more loom time. Fine mesh that still passes pollinators barely exists below 6 mm, so treat anything under 4 mm as a pollinator-free zone and plan around it.
Cabbage white butterfly exclusion
Cabbage white butterfly exclusion works at about 7 mm. The adults are large but the body is slim, and a 25 mm bird mesh does nothing to stop them. Net brassicas from planting, because the crop never needs pollination and the first generation arrives early.
Carrot fly netting aperture
Carrot fly netting aperture has to be fine, around 1 mm to 2 mm, because the fly is small and flies low. That is a pollinator-free zone by definition, which suits carrots and not much else. Keep it on its own bed.
The same fine exclusion netting handles thrips and aphid exclusion without chemicals on salad and seedlings, where a sealed cover is doing real work. It is the crops that flower that need the wider specification.
Colour, Light and the Flower Signal
Netting color and insect attraction are less connected than gardeners assume. Bees navigate by flower color and ultraviolet patterns, not by the net, so black netting does not repel them and green netting does not invite them.
Colour still matters for two practical reasons. A dark net cuts more light than a light one, which slows growth under a closed cage, and it heats the air beneath it on a still day.
Natural green and black are the finishes that disappear against foliage. Pick on appearance and light, then set aperture on insects. Netting height above flower heads belongs in the same drawing, because a cover that touches the blooms traps them and blocks the approach path.
Hand Pollination in a Netted Cage
Sometimes the cage has to stay closed through flowering, usually on a seed crop under strict exclusion. Hand pollination in a netted cage covers that case, and it takes less time than expected.
- Work mid-morning, when pollen is dry and the flowers are open.
- Use a soft brush and move between flowers of the same variety, not across varieties, unless you want a cross.
- For tomatoes and eggplants, skip the brush and shake the truss instead.
- Repeat every two or three days across the flowering window.
- Tag pollinated trusses so the routine does not double up.
Tomato truss vibration for pollination mimics a bumblebee’s buzz. Hold the truss and flick the support cane sharply for a second, every few days, and the fruit sets without any insect inside the cage.
Specifying the Mesh and Ordering It
Three numbers carry the order: aperture size, wire diameter and mesh panel size. Aperture comes from the insect work above, wire diameter follows the pest, and panel size follows the frame and the door you walk through.
For a garden cage, 1.5 mm to 2.0 mm stainless steel wire covers most jobs. Heavier wire holds a longer span and resists a large animal, but it shows against the sky and shades the crop.
Order panels to the frame rather than cutting on site. A woven panel cut badly leaves wire ends that catch skin and clothing, and a garden cage gets handled every season.
End-of-Season Inspection
A garden cage takes more handling than a fixed enclosure, because it comes down and goes back up. That handling is where most failures start, so inspect each fall.
- Check every ferrule line where the panel meets the frame, since that is where a lifted panel bends.
- Look for abrasion where netting rubs a post or a branch.
- Confirm the door still closes to the same gap it did in spring.
- Store panels flat and off the ground, never folded on themselves.
Removing netting after petal fall protects pollinators and extends panel life, because a cage left up through winter takes snow load it was never sized for. The case for treating netting as a seasonal barrier makes the same point from the wildlife side: a barrier left up year-round catches things it was never meant to catch.
For fruit trees, size the cover to the canopy rather than the trunk. The sizing method for fruit tree canopy netting sets the panel from the spread at harvest, which runs wider than the spread at blossom.
FAQ
No. Honey bees and most bumblebee workers pass 10 mm without trouble, which is why that size suits bean rows. It does stop small birds and adult cabbage whites, so it covers both jobs on a flowering crop.
Only with a wide mesh, and even then it is a gamble. Plum needs insects across a short window, so net after petal fall instead. If pigeons are heavy during blossom, net at 20 mm and accept some loss.
No. Bees respond to flower color and ultraviolet patterns, not to netting color. Black netting does cut more light than a natural finish, which is the real reason to think about it.
About 7 mm. Honey bees can work through it, bumblebees cannot, and adult cabbage whites are excluded. Use it on brassicas, which need no pollination, and you lose nothing.
Two to three weeks for top fruit, less for cane fruit and strawberries. Watch for petal fall rather than counting days, because a cold spell stretches the window and a warm one shortens it.
Get the Aperture Right the First Time
Send the crop list, the pest and the flowering window. We will return an aperture and wire diameter that lets the right insects through, then quote panels cut to your frame with a lead time.
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