Outdoor Super Skunk in pots, questions

This is my first time growing as it is now legal in Massachusetts. I have them in 5 gallon pots. They stretched due to light constraint but started to fill in nicely. As of July 29th here are the pics. My questions are why are some of the fan leaves yellowing and I have been pulling off yellows. I added a npk for flowing into the soil last week and am watering every other time with npk mix. I also just poked holes throughout the soil because I am worried they are rootbound. Two are 6 ft in the pots. The rest are about 5 feet in the pots.