MH Light/Stretch Issues...

ettubrutus

Well-Known Member
I recently switched to a 400W MH/HPS light...

The attached pic shows you how wide the reflector is in comparison to the pots... the seedlings on the sides are already starting to stretch toward the light... until I took the pic the light was 3" from the plant tops, I just backed it off to about 10"... Not sure if it will provide the amount of light needed at that height, but the light coverage is more even...

Any ideas guys and gals?
 

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Yota

Well-Known Member
Are you asking how it works? If your lights are too close, you can burn them. Kind self explanatory. While your plants grow, you run the risk of them getting even closer than you placed it and getting burned or ruined. Plus its so close and thats why you may be seeing the stretch, if its a tad higher the light is probably more even...not that the stretch you are seeing is that big of deal in the first place.
 

ettubrutus

Well-Known Member
Are you asking how it works? If your lights are too close, you can burn them. Kind self explanatory.
Actually, I am not sure it is that self-explanatory... what about the light will burn the plant? It's not hot, it's not brighter than the sun, what about it (besides the plant getting too much light?) could burn the plant?
 

uberpea

Well-Known Member
here dude, why dont you try this. 400w is a little strong for these seedlings and its hard to find a happy medium between stretch and burn.
Why dont you start out with a few cfls, they are super cheap and will get the job done while they are seedlings.
I hope this helps somehow, goodluck

Duece.
 

smurfy78

Active Member
dude if you stick your hand within 3 inches of that light for 18 hours a day your gonna have a nasty ass sun burn weather or not the temperature around the light is hot, same thing applies to the leaves
 

Yota

Well-Known Member
You can also stress your plant. Those are just seedlings, to have intense hot light 3 inches away is too much stress. Its simple, just move the light to at least 12 inches away, maybe 18. You don't need 400watts 3 inches away, in fact it can be bad. Burn/stress. I cant tell you the science behind it, just the experience.
 

ettubrutus

Well-Known Member
You can also stress your plant. Those are just seedlings, to have intense hot light 3 inches away is too much stress. Its simple, just move the light to at least 12 inches away, maybe 18. You don't need 400watts 3 inches away, in fact it can be bad. Burn/stress. I cant tell you the science behind it, just the experience.
That's understandable... and don't get me wrong, I am not arguing with you guys... this is really the first time I've done this so I am still very much learning... what I guess I am really trying to figure out is the amount of light that registers on my light meter goes down substantially as I move the light away... am I reading the meter wrong, or does it not matter because the light is so much brighter than say a CFL...? The light is about 10" away now and they seem to be doing fine, I am just trying to get a better understanding of how it all works...
 
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