Light Burn or Deficency

Cocktrauma

Well-Known Member
High my friends,
Just ja quick question.
Can you identify what lead to the yellow brown spots on my leads.
These girls are different strains 4 weeks into flower und around 400w 3500k led/1,44m2
They are all bio and only get ph corrected almost RO water.
The soil ist conditioned with some bio adds
The temp is around 24c and RH 65%

I had the lights powered up to 500w because of my ne ppfd meter which showed 700umol then but turned it down again.

Any ideas
I guess it was the to strong light but I'm not sure

Would love some ideas

Thank you!
 

Attachments

Hobbes

Well-Known Member
.

Could be just a natural aging process - the fan leaves start giving up their stored nutrients to help flowering buds.

.
 

Cocktrauma

Well-Known Member
Yes ok that would make sense
I used some spray against spidermites but just for prevention. Didn't really saw any. But I used it 3 weeks before I took the picture.

I turned the light down now for severely days and the problems did not get worst .
I think it was the light ;)

I guess the recommended maximum around 700umol is only possible at a perfect vapor pressure deficit at around 26°C.
550 should be enough in my case I guess because 23.5 is the max temp I can reach.
 

sh0wtime

Well-Known Member
I think 65% RH is a bit mucho to be honest is that next to your pots or above your plants?
Also 550 umol/s for flower seems a bit low.
The plants should be able to handle 600-800ish umol/s.
 

Cocktrauma

Well-Known Member
Can you see the white thin the air on the second picture
That's the sensor which says 65%.
In the attachment you can see the VPD chart which says 65% is cool at 23-24°C
 

Cocktrauma

Well-Known Member
But what is it then?
Yesterday the yellow spots got a bit more intense again :s
Do you think it could be Potassium Deficency?
The plants are quiet big for there pots
 

amneziaHaze

Well-Known Member
Maybe you have a big humidity change in day and night cycles.it causes weed to " cry" on the edges of the leafs making small drops of water.with light too close it becomes a magnifier glass and burns the leaf

Also what are those black spots on the leafs, bugs?
 

Cocktrauma

Well-Known Member
The black spots is just some soil
There is another veggging level above the flowering level and some fell down

I checked the night humidity and it's around 70 which is pretty high to :(
Guess I have to invest in an dehumidifier :s
 
Top