Hi Amanda: Oh, I know what you mean about squirrels. 

Here's a website with about a dozen ways that may help keep squirrels away from your pots. Cayenne pepper (or peppermint) might be the most effective. For bird feeders, we can now buy seed cakes that have cayenne pepper incorporated, and squirrels don't touch these feeders and birds aren't bothered by cayenne. Mammals, which include squirrels are averse to the hot pepper taste. It can be sprinkled on the soil but will need to be refreshed after rain etc. You can also mix ground cayenne with water and spray it on the soil. This year I'm trying the coffee grounds with cayenne spice. I'm thinking the coffee grounds may extend the life of the cayenne. 

Creating a barrier on top of the soil should also work but a layer of stones may make your pots too heavy, or you may not like the look. I've used small river pebbles on indoor plants to keep the cat out of the plant (although I could use cayenne to repel the cat!).

Most of the commercial products seem to use one of the essential oils, e.g. peppermint, cinnamon, cloves etc., and white or hot pepper as their repellents. As with home remedies, you'll need to replenish the scent as it fades. If you check out the commercial products, ask how long each packet/pellet lasts. A couple of products say they last up do 90 days. 

Hope this helps you solve your squirrel invasion!

Regards,