Is this light stress or something else?

elfo777

elfo777

Well-Known Member
I am almost certain this is light stress, but can anyone confirm? Also, is light stress the only problem? I already raised my lights and new growth seems ok, but affected leaves are yellowing fast and it happened pretty quickly. Possible overfeeding?

Water PH 6.2-6.6, light mix soil, feeding biobizz per biobizz chart fish mix and alg a mic, watering when pot feels light, 315W CMH light, about 40 cm to plants (now 65), temps are low, about 20C with lights on, 17-18C lights off (winter is rough here), humidity 60%+.
 

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Blackketch

Blackketch

Well-Known Member
elfo777 said:
I am almost certain this is light stress, but can anyone confirm? Also, is light stress the only problem? I already raised my lights and new growth seems ok, but affected leaves are yellowing fast and it happened pretty quickly. Possible overfeeding?

Water PH 6.2-6.6, light mix soil, feeding biobizz per biobizz chart fish mix and alg a mic, watering when pot feels light, 315W CMH light, about 40 cm to plants (now 65), temps are low, about 20C with lights on, 17-18C lights off (winter is rough here), humidity 60%+.
Click to expand...
Yes, in my opinion it is light stress... How are the leaves underneath?
However I think light stress brings imbalance to the plant which leads to having deficiencies which makes it more confusing on identifying the problem!
 
Blackketch

Blackketch

Well-Known Member
A few cycles ago my plants suffered from light stress because I had switched to a different lamp and didn't know how to adjust well with the height and even though I had never had problems with deficiencies on the plants, the central and closer plants started to show symptoms of multiple deficiencies... it reminded me a bit of the same situation also because it seems a bit low one CMH at that distance but my guesses are just assumptions! I will leave the word to you :bigjoint:
 
coreywebster

coreywebster

Well-Known Member
I'm one of those people that often see light stress over a nutrient deficiency.

However on this occasion I think your issues your temps. Which can cause those symptoms due to the plants inability to uptake potassium at lower temps but also cause light stress due for the same reason.

The environment is the problem.
Slow your extraction down or heat the room
 
HitSolution#9

HitSolution#9

Well-Known Member
elfo777 said:
I am almost certain this is light stress, but can anyone confirm? Also, is light stress the only problem? I already raised my lights and new growth seems ok, but affected leaves are yellowing fast and it happened pretty quickly. Possible overfeeding?

Water PH 6.2-6.6, light mix soil, feeding biobizz per biobizz chart fish mix and alg a mic, watering when pot feels light, 315W CMH light, about 40 cm to plants (now 65), temps are low, about 20C with lights on, 17-18C lights off (winter is rough here), humidity 60%+.
Click to expand...
Looks like the beginning of a potassium lockout.
 
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