Hello,

Thank you for contacting the Oregon State University Extension Service.

Tree squirrels, which it sounds like the kind of squirrels you are referring to, like the Western Gray Squirrel, are quite challenging to manage when it comes to excluding them from a vegetable garden. If you have ground squirrels or chipmunks instead, the challenges can be similar. There are a few techniques you can try, however, but due to their biology, behavior and their reliance on the surrounding habitat for survival, your options are limited.

First, tree squirrels (and some ground squirrels and chipmunks) do rely upon tree nuts, seeds, and other fruits to survive. They find these throughout their territory, including your neighbor's property, various street trees and local natural areas - much of their food comes from wild sources. So long as there is adequate food, water and space for them to survive, they'll be a part of the local wildlife. Short of speaking to your neighbor about your concerns, or contacting your city ordinance office about that property, you won't have much control on the wider territory that these squirrels call home.

You do have some control over your own property, however. Western Gray Squirrels, and if the habitat is right, the small, reddish-brown Douglas Squirrel, do frequent bird feeders, as do chipmunks. You didn't mention having feeders yourself, but if you do, it's worth considering how they affect local wildlife populations. While squirrels don't rely entirely on bird feeders for survival, having them in your yard does attract squirrels in close proximity to your vegetable garden. When such produce is ready, they do a great job of knowing exactly when they are at their best, and unfortunately, before you've had a chance to pick them! Considering that feeding birds is enjoyable for many of us, removing bird feeders might not be an option for controlling squirrels.

According to the University of Nebraska's Wildlife Extension publication on tree squirrels - see https://wildlife.unl.edu/pdfs/control-tree-squirrel-damage.pdf, there are some techniques you can try. Check out the section on Excluding Squirrels from Gardens and Lawns. They suggest either or both of the following:

• Taste repellents, like Ro-Pel (brand name), which is bitter, or the hot ingredient in chili peppers (capsaicin), but warn against applying them to the edible portions of the vegetables. Just like many of us, squirrels don't like the tastes that these products have. Treating young vegetative portions of growing vegetables that they might be nipping off can keep them away before the fruits mature - note that you must reapply repellants as they lose effectiveness over time due to rain and exposure to the outdoors;
• Physical barriers are the other option to consider. Putting up 1/2" mesh wire fencing around the garden plots, topped with electrified wire strands may prevent them accessing the garden. Cornell University -http://wildlifecontrol.info/wp-content/uploads/2016/04/Tree-Squirrels.pdf - recommends a fence at least 30 inches high with the bottom edge buried in the ground at least 6 inches deep and bent outward at a 90 degree angle 6 inches to avoid those squirrel species that can dig underneath.

Since squirrels can climb (particularly tree squirrels and chipmunks), fencing is also limited in it's effectiveness. Fencing, including the electrified sections, can be costly. Putting wire mesh around individual plants when the vegetables are at their most vulnerable may be a more cost effective and practical solution to an entire perimeter fence.

The timing of your question is perfect, as OSU Extension is hosting a free, live webinar on Apr 28, 2020 10:00 am - 11:00 am PDT. Details and registration information are at https://extension.oregonstate.edu/mg/events/dueling-diggers-gophers-moles-voles-ground-squirrels

I hope this helps provide you with some options. If you still have questions, please let me know.

Thank you for contacting the OSU Extension Service.