Clear cups= light to the root zone, which is not designed to be exposed to light. Outdoors, where plants are in sun, it's even LESS desirable. DEfinitely move them to opaque pots, or cover those with tinfoil. Also make sure they drain very well.

You should start feeding soon at 1/4 strength grow nutes, and aim for your runoff pH to be 6.7. Also, make sure that they are getting enough water. Weekly for plants in full sun may not be enough.