Hey guys. I'm doing a grow with my 600w hps and autoflowering plants (see sig) Just trying to judge the distance of the hps from the plants for seedling stage and need clarification. Is it the light intensity that is harmful to seedlings or just the temps of a closer bulb? My temps are 72 degrees when the light is 36 inches and 20 inches away but the light intensity is obviously much higher when the light is closer. What distance should it be at for seedling stage?!! +rep for answers.
I like to keep the light and heat off of them for about the first 3-5 days after they drop the shell. Then I start working them down an 1" per day until I get to my optimum distance. Now that being said, I take everything in my grows very slowly and am very casutious to change any aspect of my environment until my plants tell me something is wrong. Thats just what I do..... P.S. IDC about rep
I will be interested in what others say, but I would have to think heat cause even outside we start earlier when its cool but sun can vary day to day early in a season and later get extremely warm. But I have always weened my light down when coming from the nursery.
I useually start about 3 feet with my 600w but that second stage is also the lower lumen CMH. I am still interested what others do!
Both. But with particular concern to light intensity for fresh sprouts. Start them off on lower-intensity lighting -- either CFLs before introducing the HID or the HID starting 2-3 feet away and then lowering a couple of inches a day.
I also use a Hydrofarm Hothouse with a dome to keep the humidity up this also limits the amount of light they receive from my 400w MH. I start with the light up 3 feet from the seedlings and like I said start moving it down or them up whichever be the case.