How to
Net crops against bugs and birds
The squash went in this morning. Put the bug netting over it today, before the first cucumber beetle finds it.
Grown in Ohio, zone 6a. Your frost dates move the calendar; the signals don't. Broadfork goes by where your garden is, not its zone: frost dates for your ZIP code in the US, or the ones you type in anywhere else.
Seven minutes to read. The steps stand on their own.
Before you start#
Bug netting is a mesh, and the size of its holes decides which pests stay out. Over the squash family it keeps off cucumber beetles, squash bugs and the squash vine borer. Over the cabbage family it keeps off cabbage worms, cabbage maggots and flea beetles.
It isn't a cover for the cold. No data gives netting any warmth on a cold night, or says how hot it runs under it in summer. For a cold night, use a row cover; its lightest grade keeps insects off too.
For a crop that will grow tall, plan a frame to hold the netting up, such as the hoops of a low tunnel.
When it goes on#
Put it on the day you sow or plant, before the pests show. The weeks that matter most are early spring and again late July into early August.
- Cucumber beetles
- They mate and lay from mid-May. Net cucumbers, squash and melons at planting.
- Cabbage maggots
- The flies lay in early to mid-May. Have the netting up by then.
- Cabbage worms
- The white butterflies are out from mid-May, with 3 to 5 generations a summer; some data says usually three.
- Flea beetles
- Early spring. Net the seedlings while they grow.
- Squash bugs
- The adults fly in during late May and early June.
- Squash vine borer
- The moths fly in June, about when the plants begin to run. Some data nets at planting, some once the vines start to run, or late June to early July for bush types. Either way it comes off when they flower.
- Japanese beetles
- Late June to early July. On beans, raspberries and grapes, fine netting goes on only after they bloom.
- Spotted wing drosophila
- On raspberries, blackberries and blueberries, 80 gram netting goes on after most of the flowers are pollinated and before the fruit colors, and comes off after fruiting.
In Broadfork When a cucumber, squash, melon, cabbage, broccoli or kale planting goes in, bug netting goes on your list for that day, and a squash you log Starting to vine without netting gets the task too.
Which mesh#
Go by the hole, in millimeters. Pick the grade the pest you're netting for can't get through.
- 0.35 mm
- Aphids, flea beetles, thrips, whiteflies, spider mites and leafhoppers, and everything the coarser meshes stop. It keeps out the ladybugs and lacewings too.
- 0.72 by 0.97 mm
- Cucumber beetles. In a trial it kept them out, let the air through and gave the best cucumber and melon yields. Some data uses a 0.8 by 1.0 mm screen.
- 0.85 mm
- Leafhoppers, moths, root maggot flies, stink bugs and squash bugs. Flea beetles and aphids need the finer mesh.
- 1.0 by 0.6 mm
- Spotted wing drosophila, in the grade called 80 gram. A 60 gram net, at 1.95 by 0.95 mm, let it through.
- 5 by 3 mm
- Only moths, stink bugs and squash bugs.
The steps#
- Pick the bed. For squash, not where the squash family grew last year: the vine borer moths come up out of that soil, under the net. For the cabbage family, not where onions or root crops grew.
- Net the day you sow or plant. Don't wait for the first pest.
- Give tall crops a frame. Once tomatoes need caging, or pole beans and vining cucumbers climb, put the netting on a frame or take it off.
- Seal every edge with soil. It only keeps insects out when it's sealed all the way around.
- Take it off the squash family when the flowers open. Bees can't reach the flowers under it, and no fruit sets. Or lift it in the morning while the bees fly, and put it back for the afternoon and night.
- Leave it on the cabbage family until harvest. Only a plant kept for seed flowers and needs it off.
Watch under it#
Look under the netting now and then. Anything already on the plants or in the soil when it went on is trapped in there with them. For a pest the netting doesn't stop, or once the crop outgrows it, handle the pests as you would in the open.
Fruit that needs bees gets none under it. Squash kept netted through flowering is pollinated by hand, about once a day; a female flower needs six or seven pollinations for a full fruit. Under netting over berries, bring pollinators in.
In Broadfork Log a pest that netting is timed for, such as cucumber beetles or flea beetles, and each bare planting of the crops netted against it gets the task; the other crops it feeds on are named to check.
Bird netting#
Hang it over a frame, off the plants, and anchor or bury the edges all the way around, or the birds walk under. Over strawberries, stakes of 6 to 8 inches every 2 feet, angled outward, hold it.
Time it by the fruit, not the date. The data puts it on before or as the fruit begins to color. Birds start on grapes as they sweeten, and leave aronia alone until it's fully ripe.
Lift it to pick, and put it back at once. Pick the fruit as soon as it's ripe.
Well-managed 80 gram insect netting also kept birds off completely, and sheltered the crop from hail, heavy rain and wind.
The data gives no mesh size for bird netting.
In Broadfork Bird netting over a fruit the data nets for birds goes on your list by its expected season, or the day you log its fruit starting to color, and the app asks you to take it off when the season ends or you log it done producing.
If it goes wrong#
- Pests under the net
- They were on the plants or in the soil when it went on. Net at planting next time, and seal the edges.
- Aphids building up
- The finer meshes shut out the ladybugs and lacewings, and had aphid outbreaks in a trial. Treat them as you would in the open.
- Flowers but no squash
- The bees couldn't get in. Take it off at bloom, or pollinate by hand.
- A bird caught inside
- It came in at a gap. Pin the edges to the ground all the way around.
- The crop lifting the net
- It outgrew the cover. Move it onto a frame, or take it off.
At the end of the season#
Take bug netting down after the crop, to slow the sun's wear on it. It lasts 7 to 10 years.
Take bird netting off and put it away as soon as the harvest is done.
The exceptions, by crop#
- Cucumbers: on at sowing or planting, off when the female flowers open.
- Summer squash: off when flowering begins. Some data names parthenocarpic varieties for poor set, and those can stay covered all their life.
- Eggplant and potatoes: against flea beetles, off before they flower. Leafy greens can stay covered.
- Blueberries: bird netting before, or as, the fruit begins to color; some data waits for the first blue berries. They come into season about mid-July.
- Grapes: as the fruit ripens. The earliest ripen from about mid-August, the latest late September into early October.
- Aronia: only if you leave the ripe, black fruit hanging for more sugar.
- Honeyberries: late May or early June, as the fruit changes color.
- Serviceberries: over the ripening fruit, or pick a little early.
- Strawberries: no data gives the day. Anchor the net all the way around.
Every number on this page comes from a published extension source.
Sources for this guide: University of Minnesota Extension, Ohio State University Extension, University of Maryland Extension, Iowa State University Extension and Outreach, Utah State University Extension, Clemson Cooperative Extension, UMass Extension, University of Georgia Extension, University of Wisconsin-Madison Division of Extension, NC State Extension, Penn State Extension, University of Florida, University of New Hampshire Extension, USDA, Colorado State University Extension, Cornell Cooperative Extension, New Mexico State, University of Illinois Extension, University of Kentucky Cooperative Extension, University of Missouri Extension, University of Vermont Extension.
The documents behind this guide (65)
- Bird management in vineyards (2026), University of Minnesota Extension
- Cucumber beetles (2026), University of Minnesota Extension
- Extending the growing season: start early, end later (2024), University of Minnesota Extension
- Growing grapes in the home garden (2024), University of Minnesota Extension
- Growing strawberries in the home garden (2024), University of Minnesota Extension
- Growing summer squash and zucchini in home gardens (2024), University of Minnesota Extension
- Japanese beetles in yards and gardens (reviewed 2025)
- Squash vine borers (2026), University of Minnesota Extension
- UMN Cabbage and onion maggots (2022)
- UMN Caterpillars on cole crops (2022)
- UMN Cucumber beetles (2026)
- UMN Flea beetles (2022)
- Cucumber Beetles in Cucurbits: Identification, Damage, and Strategies for Control (2026), Ohio State University Extension
- Growing Aronia (Aronia melanocarpa) in Ohio (2024), Ohio State University Extension
- Growing Blueberries in the Home Garden (2026), Ohio State University Extension
- Growing Cabbage in the Home Garden (2018), Ohio State University Extension
- Growing Grapes in the Home Fruit Planting (2017), Ohio State University Extension
- Monitoring and managing spotted wing drosophila in fruit crops (2024), Ohio State University Extension
- Squash Vine Borer Damage and Management: What to Look for and When to Act (2026), Ohio State University Extension
- The Birds and The Bees of Cucurbit Flowers (2022), Ohio State University Extension
- The Ohio State Phenology Calendar: Understanding Nature's Biological Clock (Part 1) (2022), Ohio State University Extension
- Bacterial Wilt of Vegetables (2023), University of Maryland Extension
- Cucumber Beetles: Spotted or Striped on Vegetables (2024), University of Maryland Extension
- Growing Strawberries in a Home Garden (2026), University of Maryland Extension
- Growing Summer Squash (Zucchini) in a Home Garden (2024), University of Maryland Extension
- Imported Cabbageworm on Vegetables (updated 2024-07-22)
- Key to Common Problems of Squash (2023), University of Maryland Extension
- Squash Vine Borer on Vegetables (2026), University of Maryland Extension
- Growing Aronia in Iowa (2026), Iowa State University Extension and Outreach
- Growing Cucumbers in the Home Garden (2023), Iowa State University Extension and Outreach
- How do I stop birds from eating my blueberries? (2026), Iowa State University Extension and Outreach
- Serviceberries (2024), Iowa State University Extension and Outreach
- How to Grow Haskap (Blue Honeysuckle) in Your Garden (2015), Utah State University Extension
- How to Grow Serviceberries in Your Garden (2016), Utah State University Extension
- How to Grow Summer and Winter Squash in Your Garden (2020), Utah State University Extension
- Row Covers (2020), Utah State University Extension
- Cucumber, Squash, Melon and Other Cucurbit Insect Pests (2025), Clemson Cooperative Extension
- Growing Strawberries in South Carolina (2025), Clemson Cooperative Extension
- Protecting Berries from Birds (2021), Clemson Cooperative Extension
- Bird Protection for Blueberries and Other Fruit (2020), UMass Extension
- Cucurbits, Bacterial Wilt (2013), UMass Extension
- Squash Vine Borer (2021), UMass Extension
- Controlling Insects on Summer Squash in the Home Garden (2024), University of Georgia Extension
- Home Garden Strawberries (2022), University of Georgia Extension
- Homegrown Summer and Winter Squash (2021), University of Georgia Extension
- Degree Days for Common Fruit and Vegetable Insect Pests, University of Wisconsin-Madison Division of Extension
- Imported Cabbageworm (published 2026-01-30)
- Squash Vine Borer (2026), University of Wisconsin-Madison Division of Extension
- Season Extenders and Greenhouses (2022), NC State Extension
- Small Fruits, NC State Extension
- Growing Strawberries (2026), Penn State Extension
- Serviceberry in the Garden and in the Kitchen (2025), Penn State Extension
- Strawberries, University of Florida
- Summer Squash, University of Florida
- UNH highbush sheet, University of New Hampshire Extension
- Using Row Covers in the Garden (2020), University of New Hampshire Extension
- Low Tunnel Systems (2023), USDA
- NRCS, OH (2023), USDA
- Cucumbers, Pumpkins, Squash, and Melons (2025), Colorado State University Extension
- Thinking exclusion? (2020), Cornell Cooperative Extension
- for educational purposes (2019), New Mexico State
- Summer Squash, University of Illinois Extension
- Squash Vine Borer and Squash Bug, University of Kentucky Cooperative Extension
- Home Fruit Production: Grape Culture (2026), University of Missouri Extension
- Exclusion Netting for Spotted Wing Drosophila (2022), University of Vermont Extension
Updated 11/11/2026 · Checked against our sources 11/12/2026