Because squirrels can't digest cellulose plant matter, they need to feed on plants with a high fat, protein or carbohydrate content, making your precious blueberries a prime target. While commercial repellents are available, they have to be continually reapplied, and still don't always work. The only foolproof way to stop squirrels from eating your blueberries is to prevent them from reaching the bushes in the first place. You can do this by installing an electric fence around the blueberry patch. Electric fences are designed to produce a completely harmless, but totally effective, very-low-amperage charge. A squirrel usually only has to make contact with the fence once to get the message.
Things You'll Need
Electric garden-fencing system
Measure the area around the blueberry patch with a tape measure.
Purchase an electrical fencing system designed to keep out small animals, such as squirrels. While you can put together your own system, unless you already have the needed parts on hand, building a system from scratch will cost you more in time and money than purchasing a prepackaged system. The kit will include the fence wire, fence posts, a charger to produce the current, connection wires and grounding stakes. Select a kit with enough fencing wire to fully enclose your blueberry patch; the wire should be at least 2 feet high.
Install the fence posts and the fence wire around the blueberry patch. Push the fence posts firmly into the ground with your hands and feet. If you need to pound the fence posts with a hammer to get them into hard ground, first place a wooden block on top of the fence posts to keep from damaging them.
Run the fence wire between the posts. The fence wire should be in contact with the ground so the squirrels won't be able to slip under it.
Remove any overhanging branches from the fenced area. Trim tree branches back with a saw. This will prevent squirrels from circumventing the fence by using the branches. If there's a tree you don't want to trim, enclose it within the fence line.
Hammer the grounding rod well into the soil, precisely following the manufacturer's instructions. If the grounding rod isn't properly installed, the electric current won't be able to make a complete circuit through the wire and the fence won't be effective.
Install the charger. Attach the fence charge and connect the electrical leads from the charger to the fence wire according to the product's directions.
Energize the charger. There are two types of chargers: those plugging into AC household current or those operating on flashlight batteries. Chargers that operate off AC current are equipped with transformers that reduce the AC voltage to a safe DC level. While AC chargers don't require batteries that will have be replaced, DC chargers will run for months on one set of batteries and are good choice for locations where an electrical outlet isn't handy.
Set the multimeter to its 12-volt-DC setting. Touch the two probes of the meter to two separate spots on the fence, as far apart as the leads on the meter will allow. The needle on the meter should surge up and down slightly as the charger sends pulses of electricity through the fence. If there's no reading on the meter, recheck all the connections.
For safety, place signs warning that the fence is electrified.