Thanks for writing. There's nothing I can recommend that will guarantee the squirrels will leave your plants alone. But some gardeners do sprinkle hot pepper on the soil or make a spray with a couple of tablespoons of Tabasco sauce in a gallon of water with a teaspoon or so of dish soap.
There are also commercial squirrel repellents you can try if that doesn't work. One I know of that's pretty readily available is Squirrel Stopper: http://www.messinawildlife.com/products/squirrel-repellent.php
---Justin, Senior Garden Editor, BHG.com