400 watt 2 much?

**milkmilk** · 03-31-2010, 09:46 AM

Ok my main question is what damages plants when it comes to lights?

Does only the heat from the bulbs hurt the plants or do the uv rays hurt it as welll.

I have some 1 week old seeedlings under my 400 watt mh, i can maintain 75 degrees so the heat isnt gonna hurt but.... will the uv rays damage the plants? I can keep the 400wattmh 12 inches from the plants(stays 75 with ventalated hood)

So will my light hurt my seedlings, if the temps are low

Thanks in advance

peace and love

**diamonddave** · 03-31-2010, 10:27 AM

Originally Posted by milkmilk

Ok my main question is what damages plants when it comes to lights?

Does only the heat from the bulbs hurt the plants or do the uv rays hurt it as welll.

I have some 1 week old seeedlings under my 400 watt mh, i can maintain 75 degrees so the heat isnt gonna hurt but.... will the uv rays damage the plants? I can keep the 400wattmh 12 inches from the plants(stays 75 with ventalated hood)

So will my light hurt my seedlings, if the temps are low

Thanks in advance

peace and love

u should be ok with the MH, i put my 1 week old girls under my hps too. i would suggest keeping it between 18"-14" above the plants for the first 2 weeks, good luck, they can take the light, the sun is the strongest light ever!

good luck!

**vdavis1025** · 03-31-2010, 10:40 AM

I agree with diamonddave but will add that as your plants get bigger you can slowly like maybe evry morning you can move it a 1/2 inch closer I am not sure I have an air cooled hood too so I am guessing it may be do to uv intensity but I use a 400 watt system myself it works quite well

**CLOSETGROWTH** · 03-31-2010, 10:43 AM

Originally Posted by milkmilk

Ok my main question is what damages plants when it comes to lights?

Does only the heat from the bulbs hurt the plants or do the uv rays hurt it as welll.

I have some 1 week old seeedlings under my 400 watt mh, i can maintain 75 degrees so the heat isnt gonna hurt but.... will the uv rays damage the plants? I can keep the 400wattmh 12 inches from the plants(stays 75 with ventalated hood)

So will my light hurt my seedlings, if the temps are low

Thanks in advance

peace and love

should be ok.. but keep the distance away for the first week or so.. maybe a couple of feet til the plant adjusts, or else the high intensity light may bleach out the leaves.

Then gradually lower it til its like 12" away with an oscillating fan blowing around.

**milkmilk** · 03-31-2010, 12:29 PM

Originally Posted by CLOSETGROWTH

should be ok.. but keep the distance away for the first week or so.. maybe a couple of feet til the plant adjusts, or else the high intensity light may bleach out the leaves.

Then gradually lower it til its like 12" away with an oscillating fan blowing around.

Thanks alot,

my leaves looked like they have turned a lighter green so i moved the light 20inches away

hopefully they will love it, ty