Noob in need of help plz.

Question

I have 2 White Widow plants that are yellowing around the outer edge of the leaves and I’m not sure exactly why. Plants are on Day 53 of Veg. Soil is 50/50 mix of Fox Farm Ocean forest & Happy frog. Started in solo cup for 18 Days, transplanted into 3 Gal pot on Day 19, top fed with Dr Earth 4-4-4 on Day 40, and transplanted into 5 Gal pot on day 49. It started with one plant and then the second plant started showing the same issues. The issues has been at the top of the plant the entire time, so I’m pretty sure the  deficiency isn’t Mobile. I have 2 GDP plants in the same tent & on the same schedule and they are perfectly healthy.

mwhite9829 · Accepted Answer

Can you get a ppm and pH run off?

Mr. Grow It · Answer

Looks a lot like copper deficiency.
https://www.growweedeasy.com/cannabis-plant-problems/copper-deficiency 
Interested to see what the pH and PPM of the runoff are.