One last try on the yellowing leaves situation: Normal N loss during flower, disease or both?

*All pictures are of the C99 'grapefruit' plant on two particular bud sections:
C99 'grapefruit' bud, interveinal chlorosis, chlorotic leaves - this is typical of all the branches on this plant.

I had mentioned before that some leaves were yellowing - nearly all of C99 'grapefruit's and quite a few of C99 'pineapple' - with the two smaller plants in group 1 showing absolutely no signs of this disorder whatsoever despite them being farther from the lights. I cannot say for sure - but it is useful to note that C99 'grapefruit' and C99 'pineapple' are much larger than their two sisters, causing problems due to being heavily root bound - also these two plants reside in the uncleaned Hydroton where as the other two are in cleaned Hydtoton. This leads me to conclude that the dying from the inside of the branch to the outside is a sign of some form of root rot or damage, hence the FloraShield cleansing and it's addition to the system as a regular staple.


Same bud shot and leaves but shown in perspective with the rest of 'grapefruit'

What has me most worried now is the progression of yellow fan leaves amongst the larger plants in Unit 2. It started with C99 X BB 'bravo' & appears to be showing up in C99 X A11 'alpha.' Now, these plants could have caught whatever it is making the sick plants in unit 1 ill, but then why haven't the others in the same units gotten ill as well? This is only occurring amongst the largest plants in each unit. Perhaps it's due to an inadequate amount of root space. I really do not know. It's also worth mentioning that it is later in flower (middle of week 5) so perhaps this is a normal loss of N as I am using an Aggressive Bloom formula. I've heard it can happen. I wonder though. And it must be said - the plants are putting out nice buds.


A different grapefruit bud close up with more pronounced chlorosis - the tips are curled and burnt on some sections.

Here are the symptoms one last time. It begins on the larger fan leaves - they turn bright yellow and can stay that way for a while. When they are fully yellow their veins and stems take on a purple color although there is purpleness present in the healthy plants too. In the final phases, the leaves dry, turning brown along the edges and curling upwards at the tips and along the edges. The leaves to go last are the ones closest to the ends/buds. I realize that I may have to harvest early if this situation progresses and the plant starts to die - especially the 'grapefruit' plant.


Here is a picture of a leaf on grapefruit in mid-chlorosis

As I read more, maybe I'm having a little hysteria (in the case of unit 2 at least) over what naturally happens - nitrogen loss during flower. Perhaps that is also the case with Unit 1 to a degree, but I have to think it got too bare too soon, at least 'grapefruit' did. I know C99 loves Mg, but I am supplementing, it couldn't be lacking Mg save for lockout, which worries me. I don't know. I'm showing this to show what the problem looks like on the plant - this is the best illustration of the problem thus far, it's all there in a nutshell.


Same 'grapefruit' leaf as the first plant pictures above but in close-up. Notice the complete yellowness, the curled up brown edges.

Unit 2, I'm thinking might be experiencing a natural yellowing during flower. The yellowing is primarily large fan leaves, most of the growth remains dark and lush. Not like the bare branches of the C99 'grapefruit' plant. Any ideas are welcome as I'm stumped. I am fairly certain that the two large plants in Unit 1 have problems due to complications that I'm not entirely sure what they are, but that have left them with diminished functioning root mass. There will be a 'root autopsy' which I will post after harvest if this isn't figured out to a near certainty.

Here are some details on what most of these yellow leaves look like.

Here's a picture of a progression from mottled green to yellow to yellow with brown fringed tips:


Close up of typical yellow leaf:

This leaf has gone beyond any green remaining in it's veins & is totally yellow. Notice the brown tips and the purple stem.