Answer: There are two vegetable growing seasons in the Phoenix area and I'm afraid you've missed the first one (Feb - April) but there's plenty of time for you to plan for the second planting season (Sept. - Dec.) and lots of time for you to prepare your vegetable bed. Here's a helpful publication from Arizona State University with information on planting dates for every vegetable imaginable:
I think you will find it very helpful.
Best wishes with your garden!
Q&A Library Searching Tips