I can’t figure out what deficiency is going on? Help

Hello,
All my plants have gotten reddish purple stems , I feel like I’m just now noticing so they must have not always been reddish purple.
One of the 6 seems to be yellowing. Please help see picture

what’s wrong?

Not alot of details, but obviously your into your flower cycle, it wont hurt to just simply remove thoses leaves.
Could also be a magnesium deficiency.
Epsom salts work.
Check out some of the plant problems threads that have common nutrient deficiencies.

@paintsprayer71

75-80 F 35-45 % humidity 12/12 and I am using fox farm tiger bloom, big grow and big bloom every 3rd day or so. Regular water in between \

PH 6.5-7

how do I apply the epsom salt?

She just looks a little light on N to me. She's probably a little depleted from going through the flower stretch. Usually best to keep cranking the N to them like you would in veg for the first couple weeks of flower.

I use normal epsom salts from the drug store, make sure they arent sented, but 5ml or basically a teaspoon dissolved in a gallon is a safe ratio for follar, or just 5ml into a 4 gallon reservoir, ive done that plenty of times, with great results.i only folar feed in veg mode