Are they in the big gray/black pot or in the small clay pot?

If the latter, that's the problem.

Some things I see -- sunburn from quite some time ago; periodically short of water during the past; short of fertilizer (the pale lower leaves).

Which fertilizer did you use? How was it applied?

Must tell us more about them, including how long they've been in the pot, your watering practices, the prevailing weather, including the past several months, etc.