i've had mine about 2ft with a fan on 24/7. if you have some sort of cooling system then you can get it much lower & your plants will be more compact. another advantage of a cooling system (in a grow room) is that it also constantly has fresh air in the room so your plants have always got fresh CO2.
dreadydrug Reviewed by dreadydrug on . Recommend height for MH lighting i have some seedlings starting i was reading that having ur mh light to low will fry ur seedlings and then having it to high causes it to stretch , from what ive read 5 feet is the norm, but i was wondering what u guys thought about 4 feet high for the seedlings and im not to sure after they start growing like during veg and bloom how high i should keep it. thx guys, my average temp is between 72-78 night and day so any help or suggestions would be nice, i know i gotta test it for my self as Rating: 5