Warding off those bastards
Squirrels can be really f'ing annoying in the garden. They dig up your plants, chew on them, and usually don't even eat them. All they do is destroy! Let's be real though - the can be cute, and I really don't want to hurt them (maybe discomfort, but not hurt). Below is my research and attempts to keep them from wrecking my (mostly) container garden. If your garden is in-ground or raised beds, these methods could potentially still work as well. Either way, good luck - you're definitely going to need it!
fork it
This method consists of placing plastic forks all around the plant(s)/beds(s)/container(s) that you are trying to protect from squirrel damage. Stab the fork handles into the ground with the prongs facing up and out at the top. The two working theories on this method are that it either confuses the squirrels, or it just makes it hard for them to move into/about the area without getting poked by the prongs of the fork, which makes they don't like, and they learn not to bother messing with the area with forks. So far it seems like it's working, but the jury is still out.
squirrel kabobs
Similar to the Fork It method, instead of using forks, use the wooden shish kabobs that are used for grilling and such. Place them into the dirt, pointy side up, around whatever you are trying to protect from the squirrels. This seems to be working as well so far, but we'll see how long it lasts...
spicy mulch
This method uses crushed red pepper flakes on top of the soil. I have personally seen mixed results with this method. In order for it to be effective long term, it seems like you need to have nearly all of the soil covered with the crushed red pepper flakes. I got the Kirkland Signature Crushed Red Pepper flakes from Costco, as they are inexpensive and easy to dispense. 10 ounces costs around $3.39. Once you have the Costco container, you could get a slight savings by buying a massive quantity on Amazon or somewhere else (possibly GFS or another food service store). I probably won't use this method much because of the quantities required, but certain areas of perennials such as strawberries and asparagus I will probably continue with as long as I see success, as the perennial containers get disturbed less from planting/harvesting. I tried using less and sprinkling on the ground around containers, and that did not seem to work as well.
crap load o' cayenne
One of my first attempts at deterring the squirrels was cayenne pepper. I bought a crapload of it off Amazon, and sprinkled it on and around my beds and containers. It seemed to work well at first, but after a few days, it loses potency, and doesn't really work anymore. If it rains it loses potency even faster. I will probably use up what I have left, and not bother with it anymore because it is too high-maintenance for me.