I wouldn't use the stuff you give to your cat. If you are wanting to try the stuff, I'd go grab a lil bag of seeds or one of those little growing kits from Lowe's, B&Q, Home Depot, or where you choose to buy your gardening supplies.
That is, if you are so inclined as to garden. I however do not. I'd go for mint myself. Mint seems to make everything better.
The Tea Sipping Swordsman,