Potassium Deficiency?

Not a lot of info but looks like leaf burn,,,raise your lights...

looks mnore like a boron def....or a cal/K def combined...i would check your runoff

sonoragold said:

Not a lot of info but looks like leaf burn,,,raise your lights...

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Leaf tips are crispy on some affected leaves but it's not light burn.

Joe Fresh said:

looks mnore like a boron def....or a cal/K def combined...i would check your runoff

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Boron defs are quite rare but I may sprinkle a little borax in the mix next time. It's happening only under the light, which makes me think higher intensity, faster metabolism with a potassium lockout. The brown blotches are weird though and it's mainly upper growth. I did notice a lower yellowing fan leaf on one plant with green veins - mag def?