Fan Leaf stems turning purple

This is my first grow so I'm not sure if this is normal or not... I'm growing Big Bud (http://sensiseeds.com/cannabis-seeds/sensi-seeds/big-bud) ... In about the 4-5th week of flower and I started noticing that the stems of most of the fan leaves are turning a purplish color. I've read that this can be genetics, I've also read about it being cold weather (not possible in my scenario), and I've also read about phosphorus deficiency causing some purpling... So I'm just curious if I should adjust anything nute wise or should I just not worry about it. Figured it's better to ask than to wait and see if all hell breaks loose.

I'm using general hydroponics gro/micro/bloom... And right now I put in 2.5ml/7ml/18ml per gallon of water.

Its normal amigo, some strains go purple straight away, and some turn purple when the leaf is at it's final size n on the downwards slope. Some never purple, pretty random from what I can tell

A couple of possible scenarios:

-Soil isnt aerated enough keeping it wet and blocking uptake of P (happened to one of my plants)
Next time add more perlite to the soil. The second set of plants I did this on has very little purpling on the stem and Im going into week 3 or 4 of flower.

P lockout due to low soil PH
Added extra Dolomite Lime to the soil to keep the PH normal and Roots Organic Trinity. It has tiny amounts of everything with P being the highest of the NPK percentages (I forgot the % but its below 1). The stems wont change color back but it should keep the leaf from dying outright. If they die closer to harvest its ok as the plant is using up everything it needs to finish.

Both have happened to me

Anyone with more experience please feel free to correct me.

Thanks MysticMorris. I figured it was nothing... Bundee1 - I'm growing hydro...

my bad sudo. grow on bro!

I have a 3 week veg grow, one afgan kush and 1 wite widow and use the same nutes, my afgan kush is doing the same thing but the wite widow isn't, I'm thinking it may be genetics or something. I decided not to worry abt it.......Grow On my friend

i know what u mean. i think it's either some kind of sunblock thing that the plant creates (its only on the top and sides of the stem)..... when exposed to strong light?
or. ir might just be the opposite with low temps at night maybe.

my current grow is doing this quite rapidly. i have cool and hot temp swings so i can't say for sure

My first grow I had alot of purple fan stems the room was hot my nutes water was hot my air exchange was low I had ten 65 watt cflz in my room wich was too HOT so second gro I added an intake fan also adding frozen bottle water to my nute bucket turned off the cfl just using a 90 watt ufo mix of red blue so it's 5 degrees cooler and nutes is cooler air is exchanged 24/7 and same strain cross of ak47 n white widow now only 1 fan stem is a little purple all stems are green so check on that bro it's def talkin too you then again it's just my look on it aloha

poop balls man

The same thing is happening to me , I'm at day 23 days old from first sprout (using happy frog soil) I'm growing sour diesel n noticed today that the three bladed leaf stem is like a purple color ... The main stem and top stem is a light green but idk y the stems goin to the fan leaf are purple ..... I haven't given them nutes yet, just transplanted it from solo cup to 3 gal root pouch, so I gave her pure water and next in two days I'll give her nuts(flora nova, grow) for the first time, I hope this will help , is this something I should worry about? The next nod up is beautiful green and I toped it for the first time at the 4th node. Could this have caused the stem on my fan leaf to turn purple? Any advise would b a big help.
Thanx, GrOw TiGeR

sudodaemon said:

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I believe and this is just from my personal experience with it that the purple stems on the fan leaves are a build up of nutriets in the buds and leaves... when I did my last flush I noticed the purple stems were going back to a pale green colour from the bottom up which I’m guessing indicates the excess nutes are being used up. Don’t quote me on that just what I’ve found.

I think it could be from very strong lights especially leds my plants will get them sometimes and I notice it'll only be half purple. And the back half that wasnt exposed to the light or the rest of the stems won't have them won't be, I once had a plant half of the leaves turned purple the half that was backed in the corner was green