Grow #1

Hello When you’ll change your Time light to 12/12 . Keep using grow fertilized until third weeks of flowering. The best way , it’s to make an «  transition «  , for exemple : 75% grow feed - 15% flo feed Next week 50% - 50% And the next 15% grow - 75 % Flo . If you want a good sénescence, stop your grow feed after after third week of flowering. Good grow ++

Thats the "sexing" I think its kinda the pre start of flowering. In a week or two the flowering should be there

Congrats, your plant is officially in flower. I can see first small pistils ( or call them preflowers) she shows her sex

I wouldnt worry to much unless that starts to spread. If your in fabric planters it can be that water isnt getting to the entire root system and maybe leaving dry spots in your roots, which creates spots on leave mid way to near the top of plant. Cheers

Your ph at 6.1 is ok but you don't have the ppm amount on your page, it could be either nute burn or over watering but going by the pictures it doesn't look over watered so my best guess is nute burn but if you want to know for sure do what gmslave said.

Hey So it looks like it's the very early start of magnesium deficiency...if you notice the yellow is slowly fading in between the veins of the leaves. And mag usually hits low older leaves first. I would consider using a calmag supplement regularly...like once a week. Once i made it a regular part of the diet my plants got a lot happier. 👍