that is a T12 fixture and T12 lamp is garbage. Just find a lithonia lighting T12 shoplight fixture, which is much cheaper that what you show, and buy a T8 ballast from ebay, (used).
That lamp will not grow tomatoes period, maybe seedlings, but even that will be very poor. If you plan on using T12 lamps, you are wasting your effort. Switch to T8, and use good to search for "overdriving fluorescent" and pay attention to the type of ballasts recommended. Usually Sylvania quick tronic 4 lamp and Advance 4 lamp instant start ballast is easy to rewire so the 4 lamp ballast will drive your two lamps T8, and now you are talking!