My tent is 30x18x36 w/d/h and i have a 340w led light panel that has to go in there my , plants are autofloweing i figure they will grow around 12 inches for each gallon of soil i use, how much soil should i plant my seeds in ?
Have you downloaded and read our Free Grow Bible?
size and height is proportional to how much soil you use. Your 35" grow box is going to limit your plants height. I would suggest searching and learning how to LST (train your plants).
Meanwhile, if you fill out an “ILGM Support Ticket” We can advise you better as you continue to grow.