Burmeseanswered grow question 3 years ago Hi there, Bottom leaves turning yellow could be two reasons.Nitrogen deficiency or not getting enough light.Your top leaves are much green in colour and Since you are using low wattage LED and CFL, I assume they are yellow and falling because not getting enough light.But it's always good to check for both pH in/out and ppm in/out and make sure they are in proper range.Good luck and happy growing... ✌️