They should be submerge in
nutrient solution and then drain immediately until the next watering in 30 minutes or so all day long as long as their is day light.
That is if your timer will let you do that. If not then water less often if the roots have to sit in solution for any length of time because of the minimum time on the timer.
It also helps if you add an air stone to come on when the
pump does to add oxygen to prevent root root if the pump has to run for a longer time than need be.
Ron