They will start telling you if they need food. I do not think they will even need it for there life in that pot. They might, but they will let you know. I would just use water for now. Giving them Superthrive was a good idea. Water for now or water + superthrive.
Looks great, I think they will do great. Remember start very small on the nutrients and build your way up. You most likely will never even have to go to the full recommended dose.
It might be a good idea to get a pH kit if you do not own one. It will come in handy.
You are using good dirt that is buffered so not an emergency item or anything. (for now)
edit: They might start needing fertilizer in those pots, I did not know they were one gallon, That is a bit big for them. Still only start the fertilizing when they ask for it. prob in a week or two. small.