How far should my 400watt MH light be above my 3 week olkd 4 in high plants?

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pimpnitjc

Well-Known Member

• Sep 21, 2008

• #1

I am not sure how high to start my 400watt light above my little plants? I also have an air cooled reflector too, so heat should not be bad. And how often should I lower the reflecter above the plants and how much? Thanks

 

greenleaftoker

Well-Known Member

• Sep 21, 2008

• #2

If you can feel the heat on your hands, then it's too hot for the plants.

 

Chettybear

Active Member

• Sep 21, 2008

• #3

a good way to test is put your hand over the top of your plant/plants with yhe back of your hand towards the light, hold it there for a minute and if it is too hot for your hand after a minute it is too hot

 

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pimpnitjc

Well-Known Member

• Sep 21, 2008

• #4

I figured that there was just an average height that people with 400 watt MH start with there young plants.

 

desertrat

Well-Known Member

• Sep 21, 2008

• #5

the hand test works for older plants to protect against heat but younger plants can't take the intense light so you keep the light further away.

i keep my 600 watt mh four feet above the plants until they are 6" or so.

 

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pimpnitjc

Well-Known Member

• Sep 21, 2008

• #6

OK. Thanks for your help