Lighting Question

[bgold420]

How far should my 1000watt MH be from the tops of my plants during Veg ...
as well as how far should it be when i switch to flower with the 1000watt hps ?

 

[desertrat]

use your hand as a temperature gauge, placed at the top of the plants. lower your light as far as you can with your hand being comfortably warm but not hot. if you are using air-cooled hoods or cooltube you'll be able to get the light to within a foot.

 

[max316420]

use your hand as a temperature gauge, placed at the top of the plants. lower your light as far as you can with your hand being comfortably warm but not hot. if you are using air-cooled hoods or cooltube you'll be able to get the light to within a foot.

THANK YOU, this dude on another post told me that was wrong, and thats they way i have been measuring it for years and has worked great for me

 

[desertrat]

THANK YOU, this dude on another post told me that was wrong, and thats they way i have been measuring it for years and has worked great for me

to be fair it gets a little confusing because you measure radiant heat with your hand and use a thermometer shaded from direct light to get the ambient air temperature. both are important for growing.

 

[jdizzle22]

What if you have a reflector with the glass and fans blowing on the plants? I have a 400w hps in a yield master 2 supreme and it would seem that I can get as close as 2 inches to the glass, even without a fan blowing across the tops.
Is that still too close even though my hand feels fine?
*is the hand method EVER wrong?*

 

[bgold420]

hmm ok ... yeah my hood is air cooled with a 8 inch centrifuge fan ... light stays nice and cool ... im going to lower it tonight when my cycle starts again ....

Question .... will they really grow that much better if the light is closer ?

 

[max316420]

hell ya it will, more lumens= bigger budzzzzzzzzzzzz

 

[desertrat]

What if you have a reflector with the glass and fans blowing on the plants? I have a 400w hps in a yield master 2 supreme and it would seem that I can get as close as 2 inches to the glass, even without a fan blowing across the tops.
Is that still too close even though my hand feels fine?
*is the hand method EVER wrong?*

the hand method is perfect for measuring radiant heat, but with a strong light close up you have to worry about too much light as well as heat. by bringing the light that close you are providing far more light than the sun which can hurt your plant.

will they really grow that much better if the light is closer ?

as long as you're not exceeding 10,000 lumens per square foot they will grow better the closer the light.

 

[max316420]

honestly i have never seen a marijuana plant get TOO much light, as long as they are not to hot or burning them you'll be all good

 

[Bonzi Lighthouse]

to be fair it gets a little confusing because you measure radiant heat with your hand and use a thermometer shaded from direct light to get the ambient air temperature. both are important for growing.

Yeah he conveniently left that part out. I've had to learn about dealing with heat in enclosed spaces the hard way. BTUs, WATTs, AMPs, CFMs and Ambiant Temps. Variables and Constants, control the variables and understand the constants = big bud.

 

[Bonzi Lighthouse]

What if you have a reflector with the glass and fans blowing on the plants? I have a 400w hps in a yield master 2 supreme and it would seem that I can get as close as 2 inches to the glass, even without a fan blowing across the tops.
Is that still too close even though my hand feels fine?
*is the hand method EVER wrong?*

Yes, and in the post I answered the rule of thumb was not working for him. The fact that it works for you is great for you, but there are many far more important variables to consider.

 

[bgold420]

thanks for everyones advise , ill be lowering my light alil before its light cycle starts today !