Usually the lowest GPA to apply is between 2.5-3.0. Although that doesn't matter as much as the average GPA accepted. If the school goes solely by GPA, I've heard as high as 3.9. If it's a lottery, well, then just cross your fingers. It would be best to ask someone in admissions, they'll be honest about how competitive it is.
The majority of programs I have looked at require a 3.0, with emphasis on AP/Chem/Micro. They do state that even without a 3.0 you can apply, as they consider other aspects of your application. But I imagine that you'd have to be pretty extraordinary with <3.0.
I have seen a few community college programs with a 2.5 lower limit, but you had to have a 3.0 in your sciences.