The leaves turned yellow over night

[Karas]

What caused the yellowing of the lower leaves

Grow Type - Soil
Grow Stage - Vegetative
Bucket Size - 2 Gallon
Lights - (1) 400 Watt HPS
sMedium - 75% Perlite 25% Vermiculite
PH - 6.7-7.3
RH -80 Room Temperature -78 to 86
Solution Temperature -65 to 69
Room Square Footage - 10' x 10'

 

[trichomes]

I'd research Nitrogen deficiency first, PH a little high. The solution is within this VERY resourceful website! I see buds,,??? in grow-stage? I found this link 4 u.

Older leaves turning yellow and dying?

Older leaves turning yellow and dying?

 

[nibec]

im not familliar with that medium... but to me, it looks like hydroton.. or something similar.

in which case, the PH is through the roof. should be closer to 5.5-6.0

can you go a little bit more into detail on your medium? you say solution temp... which also leads me to believe its hydro...