SpanoonapS
Bluelighter
^ That is how I have it set up. The fresh air ducts are on the bottom of both tents. The outtake ducts are at the top. Both of my tents have -ve pressure because they are both being sucked in.
When does ventilation become necessary (ie how many plants)? Seeing all these industrial a/c units, air filters, water pumps etc is somewhat intimidating/discouraging for a newbie. I got into growing to save money...
Hey - I'm starting to see roots come out of the bottom of the drain holes... not many... but they are there. Should they be switched to 12/12 or does there need to be more? I will take pics when they wake up.
It also depends on how many plants you are growing and what size the space is. Give more details to help us answer your questions more appropriately. What lights are you using? How many plants? What size is your room? What is your yearly weather like? (always hot? seasonal?)...How much you are looking to spend?