ok there can be a few variables in this one i checked the plant today haven't visited it in 10 days.
On the last visit i upped the P and K probably a bad decision (still in veg) and this has resulted in the lower fan leaves turning yellowish.
I added more N today hopefully that will fix it. The only other thing that could have done this was the heat wave we had in the last two days also i dont water as much i let the water storage crystals do the work.
Please help
Heres the pics, the plant is just over one meter tall