Dark purple areas on leaves — genes or environment/feeding problem?

Sometime it’s just growth characteristics. Sometimes Cooler temp later in flower will bring out pretty colors a dense up buds also so don’t panic just yet. But yes it some sorta stress I’m guessing hard to determine by a picture sorry. Looks like you done a bit of defoliation of recent by your picture. If there autos yes I would say they are a bit stressed

probably cold temps at night causing the purple. might be exacerbating the other symptoms too. The cold temps make conditions for certain biological processes/chemical reactions less than optimal. the plant has shown at least some leaf damage sicne week 3 not realted to cold temps. It was definitely a bit too lush after that - overfed with N (glossy and dark) and possibly P or K, too as you have some light green new growth. So, i'd guess you had a few things amped up a bit too high and it just dominoed as the weeks went by. Need to react sooner to what the plant is telling you. Needed to dial back nutes a month ago.

Hey there good looking plants so far I have had the same problem before no problem You gave to much nutrients I suggest next time you water to give regular water and then when you return to feeding with nutrients to give them 5o% of ehat you gave them b4 Don't worry to much plants bounch back fast don't focus to much on that color on the leaves ot may not fade just wanna make sure it doesn't spread all over If it does continue to spread like a wild fire I'd surely run 5 gallons of water with no nimutes thru the soil and water the soil down. To me thou it doesn't seem like it will get to bad I don't think you like k/o them or anything. Just be cautious in the future and don't. Mix a bunch if different stuff every time you feed spread them out give them one thing one time and then another the next no need to give cal mag andnextra bloom boosters every.single time you water or even every feed I never like to give my plants the 100% of what the instructions say I always like to max it out at 50% I'd start back with 10ml bloom 5ml big bud Then every other week on a diff day than you give those nutes one week you give 10ml cal mag and factor x 5ml and then the other week 10ml micro and overdrive 5ml You can slowly increasing doeses if plants do fine

Hello mate, you have many signs of an phosphorous excess: new leaves grow thin blades and with interveinal chlorosis, leaf tips and margins burn, Calcium and magnesium defiencies, lower leaves curled. I think you gave too much nutrients and some had lock out, you could try with a big flush and just if they need it a bit of feeding. Good luck and happy harvest!!

google "phosphorus deficiency weed" , think youll finds few similarities...