Is it herb or herb?

I like buying plants at Lowe's because if my green thumb is broken, I can return a dead plant that I bought there (with a receipt that you have to copy so it doesn't fade) for up to a year! With that in mind, and the fact that I was constantly buying herbs at the grocery store, I bought some herbs for home. I have a tomato plant, a cucumber plant and some flowers of Hailey's mixed in there too. So far, so good!