HELP! top leaves turns yellow (~white)

[Sampagani]

Hi everyone!
So 22 days ago I started a new adventure and I planted 2 Bruce Banner auto (from Monster genetics) in a universal substrate under sunlight the day and led light 135w 6500K by night.
Everything was ok until 6 days ago when I noticed that the top is turning yellow (near the white).
I read that it's about iron deficiency, so I want your help to make the right diagnosis and of course give me a suitable solution with many thanks!
And what about its general aspect? it's a sativa dominant, it's tall and not like the indica (northern lights auto which are big with big green leaves).
Many thanks in advance.

[SoOrbudgal]

No thanks needed you burnt the plants up

[FunkyButtLovin]

It's pretty bad iron deficiency probably due to ph problems. If it's worth saving to you, I'd transplant it into a good soil and make sure to keep the ph under 7.

I would likely just start a new seed in better soil though.

[Sampagani]

Indeed, I think it's an iron problem at 90%! Yesterday as soon as I turned off the lights I vaporised a foliar fertilizer containing iron. The leaves today are turning green again.
The problem is that the soil is at 5.5/6.5 pH and the others ( I have 2 Northern Lights Auto and one Feminised lemon haze) are doing well! Maybe it's a problem of the strain itself! I'm really sorry to live in a country where weed is illegal : I even can't ask for soil/lamps/fertilizer...without lying about the purpose!
If I transplant it...where? There are no other substrate in the market and I can't buy online : custom's agent will stop the transportation and I'll be arrested! 😐😐
Honestly I think it's a problem of overwatering because I already lost an other Bruce bane auto due to this problem. So maybe the excess water washed out the nutriments!
Anyway I'll keep you posted and thanks for the quick help!

[bboyfromwayback]

I agree, looks like you burnt the tops to me. I switched over from HPS to LED’s a few grows ago snd I learned two things right away...first lesson is if the manufacturer says 24” above canopy, stay atleast 24” above the canopy. Second lesson, see the first lesson bc by the time you realize the lights have been too low you’ve already burnt them

[Rwise]

Back the lights off, they'll survive the burn and tell us about the soil. I see several possible problems in the leaf, most likely as FBL said there is a PH issue to go with the burn.

[Sampagani]

Hi everyone!
I think it's an iron problem at 90%! Yesterday as soon as I turned off the lights I vaporised a foliar fertilizer containing iron. The leaves today are turning green again.
The problem is that the soil is at 5.5/6.5 pH and the others ( I have 2 Northern Lights Auto and one Feminised lemon haze) are doing well! Maybe it's a problem of the strain itself!

[lalaland]

Is that ever unusual! Will save this one in the memory banks for the future

[CaptainWiese91]

My first guess was also an iron deficiency.
give it too the roots with your water feeding.

[Sampagani]

Can I water the roots with a foliar fertilizer ??

[CaptainWiese91]

Wow that I don’t know..
just thought you had some iron fertilizer of some kind

[Sampagani]

I asked an agronomist about watering the roots with a foliar fertilizer and he answered by yes! 30g of Fortal (tunisian fertilizer) in 10L of water.
now they are in the dark, I'll turn on the lights after 2h and 30min.