I think what is happening,
you are root bound.
The top of the roots get too dry
and the bottom of the root
doesn't get dry enough
You might get away with it
if you add more drainage holes
so the bottom will get dry
at the same rate as the top.
Then you may need to water more often,
more like an "ebb n flow" schedule
a couple of times a day.
It is OK to let them wilt for a few hours
to really dry out the grow media.
be brave.
measure the time it takes
to get them really dry, and thirsty, wilted,
then schedule your water/nute application accordingly.
