lightburn andor nute issue? Deelite Autoflower day75 from seed

[UberPooner]

hey guys, you think we can say this is light burn? par meter said 1070umol, I was expecting it to be 800 but I poorly accounted for plant growth. the fact that the inside shaded leaf's are fine really makes me think light burn?
ppm(x500) in 600
ppm out consistently 610
ph runoff is 5.8-9.
temps min at +-65 and max at 80,
humidity +-50.
70/30 coco/perlite
day 75 from seed

*I did just handle nute lockout from overfeeding about 2 weeks ago. my runnoff numbers are stable now. I cutdown my feeding from 900ppm to 550-600. I know I toned down the nutes so maybe this could be a nute issue?

 

[Creeperpark]

hey guys, you think we can say this is light burn? par meter said 1070umol, I was expecting it to be 800 but I poorly accounted for plant growth. the fact that the inside shaded leaf's are fine really makes me think light burn?
ppm(x500) in 600
ppm out consistently 610
ph runoff is 5.8-9.
temps min at +-65 and max at 80,
humidity +-50.
70/30 coco/perlite
day 75 from seed

*I did just handle nute lockout from overfeeding about 2 weeks ago. my runnoff numbers are stable now. I cutdown my feeding from 900ppm to 550-600. I know I toned down the nutes so maybe this could be a nute issue?

View attachment 18957003

You are on the right track friend in both accounts. It looks like nutrient burn mixed with too much light may be your problem. Mostly nutrient burn from the leaf tips. When the salts are high in the substrate it's easier to burn the leaves with less light. During flowering, I raise my lights as high as possible to keep the leaf burn to a minimum.

 

[hfm]

Hello,So with those temps and humidity I'd be looking at over transpiration also.With over transpiration you can get cavitation showing in the leaf heavily.

 

[LndRcLvr]

Hello,So with those temps and humidity I'd be looking at over transpiration also.With over transpiration you can get cavitation showing in the leaf heavily.

is cavitation where the leaves become V shaped?

 

[Hiddenjems]

They had a little nute burn. It’s probably the weak nutrient solution and super bright lights doing the damage now.

Nutrient ec is a product of vpd, temp, and light intensity.

 

[UberPooner]

Hello,So with those temps and humidity I'd be looking at over transpiration also.With over transpiration you can get cavitation showing in the leaf heavily.

Im pretty sure I see the effects of over transpiration with my leaf edges going up. the only thing I can really do is add a heater to not let min heat go so low or reduce lights. I guess I could increase humidity however im kinda scared to go over 50 with being so close to finish flower? what do you guys think ?

 

[LndRcLvr]

Im pretty sure I see the effects of over transpiration with my leaf edges going up. the only thing I can really do is add a heater to not let min heat go so low or reduce lights. I guess I could increase humidity however im kinda scared to go over 50 with being so close to finish flower? what do you guys think ?

i'm pretty sure it's the 80f+ and that contributes towards increased transpiration, not the 65f+ but ultimately it's the amount of water in the soil, the higher leaf surface temperature from the light, the rate of airflow and humidity in the room that will have the greatest effect on transpiration rates.

so dont turn your heater up is the short answer, if anything keep it on the cooler side

 

[hfm]

Cavitation is spotting and pitting in leaves by pulling to much water from the leaf surface before being able to replenish it,leaving air bubbles or embolisms in the leaf.
When your leaf serrations are erect and starting to brown on the tips is a give away. I never run my vpd over 1.2 and often at 1 if running perpetual.Im not saying other things aren't happening too,just going off the numbers alone.As they said lower your temps, raise your humidity to catch your desired vpd.

 

[farmerfischer]

Looks like potassium deficiency...
Probably because of the nute lockout..