Light Stress?

[RipCityWolf]

Hello everyone, new to the forums here, and to the cannabis growing scene in general, and was hoping I could get a general consensus as to the slight yellowing going on near the top of the plant?
She's been under a full spectrum LED ( galaxyhydro 800w, 64x3w chip sets), though with only 2 of the 4 emitters on, roughly 15inches away. Light stress perhaps?
Recently transplanted into a good quality organic soil, with light feedings on a weekly basis, so I don't see it being a nutrient deficiency, but I could be wrong; she did go through a bit of stress brought about from being root bound, but has recovered well from it. Healthy growth resumed for awhile, and now this slight discoloration near the top
Looking to take some clones off her soon, but would like to get this yellowing under control before doing so; any opinions would be very much appreciated.
Thanks!

 

[Rifleman]

A little more on the soil, watering, nutrients, and what has gone on up to this point will help with diagnosis. I'm not even going to try. I have already been wrong in the help dept once today, and Momma always said, "We know your a dummy, now shut up and learn something". And that's what I about to do. But I will comment that looking at your photo what really stands out to me is the red stems...all of them. That and the paleing of the leaves suggests a nutrient problem of some sort to me. It may be as easy as a ph adjustment, or nutrient supplement, but I don't feel qualified to steer you in one direction of the other as I have no experience in soil grows.

 

[Emilya Green]

what you are seeing in the new growth is a non-mobile nutrient deficiency. The plant is not getting one or more of the 17 elements that it needs to do the things it does. Since this is a non mobile element, the plant can not move it around from one area of the plant to the other, so only the new growth that needs it now is affected.

the problem most likely is your pH. Are you adjusting to 6.5 on all the fluids you give the plant? Strangely enough, yours looks to me like the second Boron deficiency that we have seen today. Must be something in the air?

 

[RipCityWolf]

Thanks for the replies, Rifleman, Emilya. After taking another look, I did notice that the discoloration is focused more around the new growth versus the highest part of the plant, which would most likely rule out light stress.

As far as soil goes, I used a mixture of Happy Frog and Roots Organics Original, amended with some Nutrifield coco in a 5(ish) gallon pot.
Nutrient-wise, I don't exactly have a strict feeding regimen for this plant yet. I've been doing light feedings with some of the roots organics liquid nutes I have left over from this seasons outdoor grow, but been going light on it as I didn't want to hit them too hard and throw them back into shock again; been using a mixture of the Buddha Grow with a bit of Bloom to give it a well rounded dose(keep in mind this is a mother plant and not aiming to veg it out big and flower; though perhaps she will go outside next season and make me a nice lil tree, heheh), soil is top dressed with some Elemental(calmag supplement) every other week. Recommendations on a good feeding program for mothers? As well as on a good cheap veg/micro nutrient that would provide a nice well rounded feed? I'd rather avoid using the Nutrifield line I recently bought, haha; saving that for the flood an drain setup I've been working on, which will be up an running just as soon as I can get this plant looking good again to provide healthy babies for it

When it comes to pH, I haven't actually done any sort of adjusting in terms of that. I had sort of assumed since they were in soil, it would provide a decent enough buffer to not have to adjust a whole lot. We have pretty good quality tap water in this area, too, so not using RO or anything. After seeing you mention a Boron deficiency, I read up on it and saw that it is best absorbed when the pH is 6.5 or below; our tap seems to come out right at 7, so perhaps that could be the reason. Though it is strange; the two outdoor plants I had this summer were doing great(up until I got raided by crop ninjas, that is *sad face*), and not showing any of that yellowing around the new growth, and were watered with the same unadjusted tap.
I'll have to pay a bit more attention to the pH of the nutrient mix, maybe try lowering it if it still seems too high. Though in combination with the red stems, perhaps she is just hungry and I need to up the feeding a bit?

Again, many thanks for the replies the input is very much helpful; and Emilya, your explanation helped clear up what exactly is the difference between a mobile and non mobile element; thank you for that!