Hi, im new here, been reading a lot, just started my first grow in my attic, got 10 sprouts now under 3 flourescent strips, been growing a week now, they have their first leaves popped out and 2nd lot on their way, i got a couple of 400 w hps lights here all strung up, my question is, can i turn these hps lights on now or do i have to leave them under the flouros a bit longer, and if i can turn them on, how far above my plants should i keep the lights? i have a large oscillating fan on them all on the lowest setting, but will my plants stretch too much if i turn the hps on now?
Hello man, welcome there are all sorts of specs for how close the lights can be. rule of thumb is as close as possible without burning. to check that hold your hand above your ladie for awhile if your hand feels as if its too hot then your plant would think so too. i have a 400 watt hps too and mine is aprox. 9' from plant tops. also though in smaller areas heat will build much easier and you gotta watch for wilting. i moved my op from a 100 degree area to a 70 so their much happier grew an inch last night because the topped shoots (cut a week ago) decided to wake up last night.
It sounds like things are working well for you I would not move my seedlings under the big lights until they have developed at least four or five sets of leaves. Good growing
so i said rule of thumb warmth on hand. warmth on hand burnt mine you can see under my net potting post in beginners. i moved mine to 20 inches
thx for the replies guys, got my lights 2.5-3 foot above the little bleeders, got my 3rd set of leaves comin out now, no burn, temps at 25-30 degrees celsius, depending on wether its night or day, got me an extractor fan above the lights too sucking that warm air out, have had a little trouble with overwatering on a couple of them, but they seem to be recovering now they are drying out and watered only every 3-4 days, trying not to keep checking them so often and just let em get on with it, got a bit carried away with the water squirter in the first week, lol
i allways go 4" per 100watts, unless you can get them closer with a good air exchange.........the distance you have now is fine till they get and slowly decrese the distance of the light every few days by an inch or so.............good luck.......Peace out..........Sid
quicker and also helps to bush the plant out more rather than vertical height.........the lumens emmited from the light decrease over distance, so the key is to have it as close as possible without burning, this also helps to give you compact buds, rather than airy ones, increasing yield.........all in all, it's better.......lol.........during flowering, i can find myself ajusting the light height nearly every other day..........Peace out........Sid