Balcony/terrace grow in Sardinia

on 05-21 i gave them nutrients and topped them. for now it seems that we got rid of the aphids, but on 05-23, i did LST on them and i used again a bit of neem oil, just in case some of the aphids I found past week is still here. Anyway, im a bit concerned about W.Zkittlez#4.. today, on 05-24 i measured the PH and seems its ok (6,7), and i dont know what's the problem with her. she has brighter and thinner leaves than the others, and is not growing properly. Also i think she has a poor radical system, in fact her pot is drying a lot slower than the other pots. i tried to make a few holes in W.Zkittlez#4's pot to ensure an airflow to the roots , perhaps this will help her to grow like the others