Building a Wire-Topped Bird Net Frame Over Blueberries with 12-Gauge Utility Wire: Four 10-Foot Posts, Six Wires with Brick Weights, and a 33 x 35 Foot Net

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Over a 16 x 18 foot blueberry planting, set four 10-foot 4x4 posts 2-1/2 feet deep, lay 12-gauge galvanized wire across the post tops on all four sides plus two diagonals, and hang a brick on every wire end to keep it taut. That takes about 212 feet of wire and a net at least 33 x 35 feet.

How high should a bird net frame over blueberries be?

Build the frame at least 7 feet high so 6-foot bushes have headroom and the net stays off the fruit. Ten-foot posts set 2-1/2 feet deep leave 7-1/2 feet above ground, which also lets you walk or crawl under the net to pick.

UMass Amherst Extension's bird protection fact sheet uses 9- to 10-foot treated 4x4 posts set at least 2-1/2 feet deep, spaced 15 to 18 feet. It says #11 or #12 galvanized wire works, with each wire cut to the span plus about 8 feet per end, loosely stapled on the post tops, and weighted with 1 or 2 bricks hanging about 1 foot off the ground.

Clemson Cooperative Extension's berry netting guide makes the frame about 1 foot bigger than the bushes on all sides and at least 7 feet high for 6-foot plants. It pins the net to the soil with sod staples every 2 to 3 feet and puts the net up near the end of flowering.

Wire Lengths for a 16 x 18 Foot Frame

Wire	Span	Cut length
2 short sides	16 ft. each	32 ft. each
2 long sides	18 ft. each	34 ft. each
2 diagonals	About 24 ft. each	About 40 ft. each
Total	6 wires	About 212 ft.

Each cut length is the span plus 16 feet, which is UMass's 8 feet per end; the diagonal span is the square root of 16 squared plus 18 squared.

Materials and Tools

• Hillman 12-gauge utility wire, about 212 feet; check the length on the spool label
• Four 10-foot pressure-treated 4x4 posts and gravel for the holes
• Twelve bricks, a box of fence staples, and four plastic bottle tops for the post caps
• Bird netting at least 33 x 35 feet and about 28 sod staples
• A post-hole digger, a level, a ladder, a hammer, and lineman's pliers

Frame Steps

1. Lay out the corners. Mark a 16 x 18 foot rectangle that sits about 1 foot outside the bushes on every side.
2. Set the posts. Dig each hole 30 inches deep, plumb the post, and tamp the backfill.
3. Cap the posts. Slip a cut-off bottle top over each post so the rough end can't snag the net.
4. Cut the wire. Cut two 32-foot, two 34-foot, and two 40-foot pieces.
5. Lay the perimeter. Drape each side wire over its two post tops with 8 feet hanging off each end.
6. Add diagonals. Run the two 40-foot wires corner to corner so they cross over the center.
7. Staple loosely. Drive one staple over each wire on each post top, leaving it free to slide.
8. Hang the bricks. Tie a brick to every wire end so it hangs about 1 foot above the ground.

At the end of bloom, pull the gathered net over the wires, spread it to the ground on all sides, and pin it every 2 to 3 feet.

Frame Mistakes

• Tying wire ends off tight, so heat and cold sag or overload the posts
• Leaving post tops bare, where the net catches and tears
• Leaving gaps at the ground that let birds in and trap them
• Netting before bloom ends, when pollinators still need access

The same wire works for berry canes in building a two-wire raspberry trellis with 12-gauge galvanized wire. For low fruit, compare building a 4-by-8 strawberry bed cage with hardware cloth walls.

Rabbits and voles at the base of the bushes call for the right mesh from the hardware cloth mesh size and gauge guide.

For the post holes, follow hand-digging 8-inch holes for wood line posts.

FAQ

Why bricks instead of tying the wire off?

UMass notes the hanging weights keep the wires taut regardless of temperature, so nothing needs retightening.

When should the net come off?

After the last picking. Pulling it early leads to tangles and lost fruit.