SICK with What?

[Vitreous]

I have approached the last couple weeks before harvest, and I would like to share what I have been dealing with for the last couple weeks that just seemed to appear out of nowhere!.
At first I lost my mind, because I have not encountered such issue before. Live and Learn right?!
So any how, I did the research and yes It could have been a few things, but In the end I decided to go with monitoring the PH like a hawk.
I could have ran out and bought cal-mag and other nutrients to boost what I believe was possible lack of, but no I reacted quickly and did a days flush and ran a fresh cycle of nutes and PH the piss out of it.
I am guessing the G13 White Critical is somewhat on the sensitive side when it comes to her bath water!
I would still like to know if this has occurred to any one else?
The symptoms are simple....look at the photo and picture 50 percent of the upper leaves affected. Keep in mind NONE of the lower leaves did this. Some leaves started with brown spots (PH) and turned yellow. Some leaves started with yellow spots and then turned brown! Still a bit scared that this may affect the end result. Which is still slowly spreading to the smaller leaves on the flower.
Today the plant is a deep green lots of resin with heavy scent. The plant shows no signs of drooping, just kind of a mellow growth and appears the flowers are still getting thicker.

[alltatup]

Hey Vitreous, I recently was reading about calcium deficiency which plagues the upper leaves with spots. You might want to look into that a little bit more. If you gave your plants a good flush to make sure it wasn't nute lockout, try some calcium supplement if you think that the symptoms fit the profile.

[NebulaHaze]

Spotting on the leaves, even the sugar leaves, wont hurt your buds. Its just cosmetic

is it happening most to the parts of the plants that are closest to the light?

[Vitreous]

Haze. I would say yes! But not really. Most of the yellowing was almost all upper, not particularly the top top. The tops are colas and have sugar leaves not quite affected. Seems to be majority of the fan leaves. Today after peeking, I noticed the leaves are starting to die completely, and small areas down below are starting to yellow spot. Hard to tell if the spreading above has stopped. This coming Sunday will be the final week of nutes before I start a small flush. Almost seems pointless to introduce a calcium supplement? I sure hope your right about cosmetic, I will owe you big time for that vote of confidence! Although I seem to lean in your direction based on " I think the buds are still thickening!".

[NebulaHaze]

Is it possible to post a picture of the whole plant in the setup under the lights? I agree if you're going to harvest in 2 weeks there's probably not much a supplement will be able to do for you in that time. Do you have any pictures of the buds so we can get an idea of how long you have left? What is your growing medium, and what nutrients have you been using? How have you been checking the pH?

[Vitreous]

This strain from G-13 seems to be the most sensitive I have encountered. It is a hydro, flora nova expert nutes under 600HPS. I will upload some shots below!

[Sheesh]

This late in harvest I wouldn't worry too much unless the buds are having major issues. All my grows have at least one plant with yellowing late in harvest and it never has caused issues. If you read Nebula's GWE tutorial on harvesting, she points out that yellowing and discolored leaves are common in late flower but won't hurt the buds. Just try to chop before the sugar leaves are affected so you're finished buds don't show too much discoloring.

[Vitreous]

Forgot to mention PH I test twice daily. I keep the range close to 5.7 - 5.9, I did slack and as a result. I may have to go take more shots as these photos make it appear quite normal !

[NebulaHaze]

First off, your buds look amazing! They are fattening up nicely, and just very pretty overall. I've seen this leaf symptom exactly. I think it may be partly Calcium, but also a combination of things. In my case, the symptoms seemed to be worst closest to the light, and wherever it was hot. I believe moving the light up a few inches may help prevent it from spreading as quickly, even if light burn is not necessarily the root cause of the problem.

I also might try letting the pH range go up higher. It's good to let it range between 5.5-6.5 pH, because some nutrients (including Calcium) tend to be easier for the plant to absorb at higher pH ranges. This is because the actual chemical form of the nutrients changes at different pH ranges, and some are easier for the plant to access through the roots. Do the leaves feel sort of stiff? The color of the leaves also just seems a touch off, and I think it may be pH related. I would also consider possibly backing on nutrients just a tiny amount because the leaves seem a little bit dark for this stage in the flowering stage, especially around the edges where their isn't a lot of light to help use of the Nitrogen. Maybe pH some plain water and add a little bit to the reservoir next time you top off, as opposed to adding more nutrient water. You don't want to starve the plant and cause all the leaves to turn yellow because you still have a few weeks left, but you do want to consider trying to prevent any buildup of extra Nitrogen (what makes leaves green) in the plant since you're getting to the home stretch.

Just curious, what is the temperature and humidity in there?

Overall, the symptoms look pretty minor, and are only affecting very few leaves right now. It's definitely something to keep an eye on, but even if this spreads it won't hurt the potency of the buds. Whatever you're doing is working, because your plants look great!

[Vitreous]

Thank you for your insight. I want to say we are definitely on the right track diagnosing these evil girls! I know we do not have long to go, see the pic of trichs.
I normally do not let the ambers get to out of control! Also see closer at the yellow spots on the leaves. Today after review It is more noticeable and this just could be from the leaves continuing to go through the cycle and die off, or it is spreading, hard to tell.
As for my PH each Sunday is when the water change is renewed and I start the week off at a 5.5 each day it rises slightly and when it reaches 6.5 or more I bring it back down to 5.7 - 5.9 .....I don't seem to have drastic reactions with this process. As I have done this for each grow in the past. The only difference is I am using a much more quality strain than before!
Oh my light is in a cool tube so the temp averages 27*C
Humidity hangs out at 30 - 35
Should I cut the infected fan leaves off?

[NebulaHaze]

I personally leave the nutrient-deficient leaves on unless I'm defoliating them for another reason. The plant isn't as pretty like that, but I feel it offers more protection by giving more leaves to help slow the spread of symptoms. If you take a sick leaf, the symptoms will start on another healthy leaf sooner. That being said, I often remove sad leaves right before pictures

[Vitreous]

[Vitreous]

Just wanted to close off this issue, I felt it was still kinda open, based on the excellent responses given.
That was my 9th grow and like I had mentioned before, never experienced that symptom...So what I ended up doing was nothing because it was basically at the end of its life.
But I started grow #10 using the same G13 seeds and the same methods I always use, but started adding little amounts of CaliMagi through-out the grow, and presto, no symptom like that showed up.
The 10th Harvest is just next week and boy oh boy, she looks delicious and the only yellowing found is standard lower leaves and top harvest leaves are just beginning.
Love it.
Thank you all whom had bits and pieces of advice.