Blueberries are a highly valued crop in home gardens and commercial operations, prized for their flavor and nutritional content. Unfortunately, this sweet fruit is also a favorite target for numerous bird species, including robins and starlings, which can quickly consume an entire harvest. The most reliable defense against this loss is exclusion netting, which creates a physical barrier the birds cannot breach. Successful protection relies on precise timing and proper installation technique to ensure the barrier is effective and maintains the health of the plants.
Identifying the Critical Window for Protection
The decision of when to cover blueberry bushes is the single most important factor for maximizing harvest yield. Netting should be installed significantly before the berries reach full ripeness and change color from green to blue. Birds are initially attracted to the bushes once the fruit begins to show a blush of pink, red, or purple, signaling the start of the ripening process.
Waiting until the first blue berry is visible is often too late, as birds are highly efficient foragers and can strip a bush quickly. Initial visitors, sometimes called “scout birds,” locate the food source and return with the flock, leading to rapid crop loss. Applying the netting when the fruit is still firm and mostly green, but after the petals have dropped, prevents birds from establishing a feeding pattern.
Local factors, such as bird population density and regional climate variations, affect the exact timing. In areas with high numbers of fruit-eating birds, covering must occur earlier to prevent initial foraging. For practical purposes, the netting installation should be completed approximately two to three weeks before the fruit is expected to mature.
The removal of the netting is just as important as its installation to ensure a safe environment for wildlife and prevent damage to the bushes. Once the final harvestable fruit has been picked, the netting should be taken down immediately. Leaving the barrier up for extended periods increases the risk of birds becoming entangled in the material.
Selecting the Right Exclusion Material
Effective bird exclusion depends on selecting a netting material with the correct physical specifications to block small birds without affecting air circulation or sunlight. The mesh size is a primary consideration, where openings should be no larger than three-quarters of an inch (0.75 inches) to prevent birds from reaching the fruit. For smaller, more persistent species, a mesh of one-half inch (0.5 inches) or even one-quarter inch (0.25 inches) is necessary to ensure their beaks cannot pass through the openings.
Netting material typically consists of woven polyethylene (PE) or polypropylene (PP) plastic, offering different levels of durability. High-density polyethylene is a UV-treated, durable option that can last for several seasons. Polypropylene tends to be less durable with a shorter lifespan. The netting must be sturdy enough to be used season after season without tearing, which would compromise the barrier.
The color of the netting is a secondary consideration, with options commonly including black, green, or white. Darker colors, like black or deep green, tend to blend into the environment better and are less visually intrusive. White netting is highly visible and may help deter some birds, though its reflectivity might increase the temperature underneath slightly.
Crucially, the netting must not rest directly on the blueberry bushes, as this allows birds to perch on the material and peck the fruit through the mesh. A support structure is required to keep the netting elevated and several inches away from the foliage. This frame can be constructed using materials like PVC pipe hoops, wooden stakes, or metal conduit, creating a true exclusion cage.
Step-by-Step Installation and Removal
Before the frame is installed and the netting is applied, the blueberry bushes should be lightly pruned to remove any errant branches that could snag the material. This preparation ensures a smooth installation and prevents accidental tearing of the netting during the process. Any debris or obstacles around the base of the bushes should also be cleared to facilitate securing the bottom edge of the net.
The frame must be temporarily assembled around the plants, using stakes or posts placed around the perimeter to create the required height. Simple structures can be made by bending PVC pipes into hoops or domes over the row, which keeps the netting suspended above the canopy. The frame’s structure should be tall enough to allow for easy access underneath for harvesting, often six to seven feet high.
Once the support structure is in place, the netting is carefully draped over the frame, ensuring it covers the entire area with no gaps. The netting must extend all the way to the ground on all sides. The bottom edge must be securely fastened to the soil using landscape pins, sod staples, or heavy objects like rocks or bricks. This ground seal is necessary because birds, especially robins, will attempt to crawl or tunnel under the barrier to reach the fruit.
For ongoing maintenance and harvesting, temporary access points need to be established to avoid lifting the entire net. Sections of the netting can be secured with clips or ties, allowing them to be folded back for watering, weeding, or picking the ripe berries. Alternatively, the netting can be secured in a way that allows a person to crawl underneath to harvest without fully removing the barrier.
After the final harvest, the removal process must be handled with care to preserve the material for the following season. The netting should be gently lifted from the frame to prevent it from snagging on branches or support posts. Once removed, the netting should be cleaned of any debris, folded, and stored in a dry, shaded location to protect it from ultraviolet degradation.