first off you need a way to check your pH. you can get by for the time being with a freshwater aquarium kit. you can find one for ~$7. if you intend on taking this seriously you'll want to invest in a digital pH pen.

when your nutrient mixture doesn't fall within a range of 6.3-6.8 in soil, you get what's called a nutrient lockout. or sometimes it will allow too much of one element to be uptaken and this can cause another element to be locked out.

your lights need to be kept within 1-3" from the tops of your plants. the lack of light was the reason the lower leaves yellowed and fell off. you are going to want to add way more light when you decide to flower.

there is no need to foliarly spray your plants unless you are trying to fix a deficiency. this just adds moisture which can lead to mold.



-shake