what could be happening?

[GrowinGreen23]

I am in my 12/12 cycle for my plants and i noticed today that the tips on about 2 leaves are a yellowish color anyone kno what this could be, i have given them liquified worm poo for nitrogen and have given them some water, what else can it be?

[mobay]

if your tips are yellowish i would raise the light a little bit, sounds like they are starting to burn.

[GrowinGreen23]

even on the ones that aren't that close to the light? the ones that are the right under the light are fine?

but i shale raise them a little

Thanks