Raises? When/How?

Hi everyone! So I am working with a home health company. It is a relatively new job, and i'm almost at 90 days on the job.

My boss is very happy with me; the client I work for is extremely happy and have offerred to be references for me....basically things are going really good.

I am just curious, because i have a performance evaluation coming up after my 90 days are up. Would it be appropriate to ask for a raise at that time?

When is it appropriate to ask for a raise? If it is inappropriate to ask for a raise after 90 days, when would it be appropriate? How would I go about doing this? I was thinking of saying something like : "When is it typical for an employee to be considered for a raise?" I wasn't told anything about raises before being hired and i've combed through the initial paperwork....no mention of raises.

What to do?