Upper leaves yellowing (maybe bleaching?) Help please

[ManicOrganic]

I have 4 of my 8 plants that are showing a yellowing or possibly light bleaching. Not sure what the issue is.the upper leaves are going yellow (white ish ?) Bottom leaves seem unaffected. Started with one plant a week or so ago and has progressed to three others. (All the larger plants. The smaller 4 plant are not having issue yet.

Background: seeds are a mix of mephisto freebees. They are at about 4 weeks old. 5 gal fabric pots. 25% happy fron soil. 75% pro mic hp. Using advanced nutrients bloom a/b following taNge original feeding schedule. I have 6 led running on 24" heat sinks. Potential of over 600 watts bout only running at 120w per bank of lights (360 watts from the wall) lights are 25"-28" from the top of the plants.

 

[Towlie]

I'm no expert but looks like a magnesium deficiency mate have you got any epsom salts it's a good source of magnesium

 

[Towlie]

https://www.autoflower.org/threads/self-diagnose-your-plants-basic-deficiencies-list.11/

 

[THE BEAR]

I'm no expert but to be safe I'd dip your foot in Epson salts

 

[Olderfart]

I have 4 of my 8 plants that are showing a yellowing or possibly light bleaching. Not sure what the issue is.the upper leaves are going yellow (white ish ?) Bottom leaves seem unaffected. Started with one plant a week or so ago and has progressed to three others. (All the larger plants. The smaller 4 plant are not having issue yet.

Background: seeds are a mix of mephisto freebees. They are at about 4 weeks old. 5 gal fabric pots. 25% happy fron soil. 75% pro mic hp. Using advanced nutrients bloom a/b following taNge original feeding schedule. I have 6 led running on 24" heat sinks. Potential of over 600 watts bout only running at 120w per bank of lights (360 watts from the wall) lights are 25"-28" from the top of the plants.View attachment 1341206View attachment 1341203

IMO, not magnesium - that would show up on lower leaves first. I doubt that the problem is light intensity, but that is possible. I think it more likely that the happy frog in your mix has you in some kind of lockout due to an imbalance with what is already in your mix and what your nute package is providing, but I am not the person to figure this out for you.

Your best bet to figure this out is to fill in the infirmary form and ask @Mañ'O'Green for his opinion.

Good luck with it.

 

[ManicOrganic]

Ya i was thinking mag deficiency to but it only the tops effected. I foliar fed with Epson salt last week and gave them a lite does of calmag (2ml per gal) 2 days ago when i watered. No effect on the issue as far as i can see. Using advanced nutrients "ph perfect" so i have not been checking ph every watering. I did check it the first time and the ph was somewhere in the mid 6's. All i have is ph drops test so no exact reading. Seems like it has to be a lockout issue but idk for sure.

 

[Mañ'O'Green]

Ya i was thinking mag deficiency to but it only the tops effected. I foliar fed with Epson salt last week and gave them a lite does of calmag (2ml per gal) 2 days ago when i watered. No effect on the issue as far as i can see. Using advanced nutrients "ph perfect" so i have not been checking ph every watering. I did check it the first time and the ph was somewhere in the mid 6's. All i have is ph drops test so no exact reading. Seems like it has to be a lockout issue but idk for sure.

Feeding single elements will cause a lock-out. More than likely too much magnesium or calcium and magnesium.

If you are not running HID lamps you are very unlikely to get light burn unless the plant actually comes in contact with the diodes. Cannabis can easily tolerate over 2000 PPFD and most LEDs barely do that at 12 inches. I have lamps that can crank out over 2500 PPFD 4 inches from tops and they did not burn.

Read this about keeping nutrients in balance:

Tutorial - A word on Nutrients

The proper use of “salt” based fertilizer to grow Auto Flowering Cannabis. Salts: Natural and man made any chemical compound formed from the reaction of an acid with a base, with all or part of the hydrogen of the acid replaced by a metal or other cation. Learning how to use salt based...

www.autoflower.org

 

[ManicOrganic]

thanks man o green. that was a good read. I dont think the foliar feeding with epson salt water or the lite does of calmag was the cause of the problem though I cant say if it made it better or worse. I didn't use either tell after the leaves started to yellow. I am using this feeding schedule https://www.autoflower.org/threads/tangs-easy-auto-feeding-schedule.47290/ by a member named taNgs. My thought at this point is that the advanced nutes "ph perfect" may not be perfect and that by not testing every time my ph has gone off causing a lock out of one or multiple elements. But thats just a guess. the only thing that I variated on with taNgs feeding schedule is im using pro mix hp with a small amount of happy frog soil added. and I added greatwhite as directed to add mycorrhiza (even though pro mix hp says they have already been added to the mix) i dont think an excess of the mycorrhiza would have much of an effect or lead to this problem . at this point idk if I should flush with strait PHed water or if i should continue feeding as directed in taNgs feeding schedule but check my ph to make sure it is in the6.2-6.5 range?

 

[ManicOrganic]

What i dont understand is that all the plants got the exact same everything but half are showing this and the other half not. I do believe its an iron or zinc lockout/deficiency not sure on how to correct it though. I have never flushed to correct soil ph problems. I have been reading about flushing but it seems like a very arduous task to pass that much water threw the soil without doing more harm than good. Im wondering if the process is the same to change the ph as it is to flush over fertilized plants. How do you contain that amount of run off and not have your soil so water logged that it won't harm the plant. Im regretting try new things. Should have just stuck to normal soil and botanicare nutes and hps lights lol (here is a pic of a healthy plant next to one of the ones showing issues.)