Distance of the light to plants?
- Thread starter Gza
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say no 2 soap
Active Member
6-12inches,best Way To Do It Is Sit Your Hand On Top Of Plant,if The Light Burns The Back Of Your Hand You Know It Will Burn Ure Plant
korvette1977
Well-Known Member
^^^^^ e nuff said .... Thats the Ticket
Ativas
Well-Known Member
With all due respect to say no 2 soap's opinion, 1 foot is about the closest you should put a 400w lamp. The rule is to put your light as close as possible to the plant without causing heat damage. This is almost always no closer than 1 foot, and even then you need good ventilation to make that distance workable. You would need some pretty dramatic, outstanding ventilation to get as close as 6 inches.
Having said that, since your plant is only 1 week old, 2 to 3 feet away might be more appropriate at this time. A plant that age doesn't require a lot of light, but at the same time, cannot handle high temps at all. I'd put it 2 - 3 feet away and slowly move it closer, up to the 1 foot mark as the plant gets older. Good ventilation will be imperative by that time, and still important throughout.
Having said that, since your plant is only 1 week old, 2 to 3 feet away might be more appropriate at this time. A plant that age doesn't require a lot of light, but at the same time, cannot handle high temps at all. I'd put it 2 - 3 feet away and slowly move it closer, up to the 1 foot mark as the plant gets older. Good ventilation will be imperative by that time, and still important throughout.
korvette1977
Well-Known Member
sounds better and hey what do i know I use CFL's to grow tomatoes.. Thanks for the info
say no 2 soap
Active Member
ALL I WAS TRYNA DO WAS GIVE HIM A ROUGH IDEA,EVERYSETUP IS DIFFERENT & U ARE RIGHT 6INCHES IS 2 CLOSE WIT A 400W,BUT HE CAN STILL USE HIS HAND TO TEST IT,ITS ALL 1 BIG LEARNING CURVE FOR US ALL
Ativas
Well-Known Member
No need to get angry; you gave your opinion, I gave mine. That's what it's all about.
GZA:
Incidentally, I don't know if I need to clarify or not, but the 1 foot I was talking about was meant for HID lamps, 400 watts and above in particular. When it comes to CFLs and regular fluroescents, go as close as you want, in fact, it's necessary.
say no 2 soap
Active Member
sorry man didnt mean to come across as bein angry
FilthyFletch
Mr I Can Do That For Half
well at the young of a plant I wouldnt even have an hid light on it if its from seed Id have florescent 4 foot tube light on it.Now as far as a small 400 watt hps light I keep mine about 6-8 inches from the tops.600 watts about 10 inches and a 1000 watt light about a foot.Easy test is the hand test. place your hand palm down at the top of the plants and lower the light til the back of your hand just begins to feel uncomfortablly hot then up 1 inch and your good
cheetah2007
Well-Known Member
with all due respect to you Ativas, but i think that everything depends from how well is that HPS vented. i'll say that if you put the light on a 12" distance will strech the plant a lil bit, but jus a lil.if it have a cooltube the distance could be lowered to 6-8" . that wil be the best.(all imo) cheers!!! Cheetah
That70sGrow
Active Member
I would never put a 1 week old plant closer than 2 feet from a 400 watt light. Even then it might not be able to take it, they don't need much when they're so young, not at all. I agree with Ativas about the 6 inch thing. How could you ever get a plant that close without burn problems is beyond me and I'm not exactly new at this. I guess to each his own but I think I'll err on the side of caution.
FilthyFletch
Mr I Can Do That For Half
In my distances I dont use cool tubes or reflectors with glass or duct fans those are just open reflectors above the plants with a fan blowing bewteen the tops and the light
That70sGrow
Active Member
I'm an old school guy and haven't tried a cool tube. How good do they really work? How much difference, say, at one foot between a cool tube and a regular 400 watt? Thanks man.
cheetah2007
Well-Known Member
never use one(so far), but i'm leaning on some experts opinions
. the distance could be shortened from 12 to 6-8" . that's atleast 4" Less.found this, but keep in mind it says that it doesn't consider the heat just the amount of light, so don't actually don't know how helpful it is. Can plants have too much light? Or is it that its too intense up close? My top leaves are at a slight upward angle, thought i read somewhere that it was because they are trying to minimise the light they recieve, is that right? should i move them away a bit?
edit: when everyone says about the hand thing do you actually mean burn your hand, like you have to move it away, or just get warm, i could keep my hand under my 250 watt hps all day, just gets a bit warm
edit: when everyone says about the hand thing do you actually mean burn your hand, like you have to move it away, or just get warm, i could keep my hand under my 250 watt hps all day, just gets a bit warm
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FilthyFletch
Mr I Can Do That For Half
The hand thing means till it just feels uncomfortable doesnt burn ya but you feel it geeting real warm and not a temp youd enjoy all day