lighting and distance
- Thread starter THEDOO
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eloquentsoution
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the big advantage i see to cool tubs is a vertical hang which increases useable light by 10% and the vegetation can touch them.
someone correct me if i am miss informed on temperature and distance. as far as free hang goes. i do it. there is an exponential diminish of light with distance, rather then linear, for this reason and repeated tests, i am sure of increased return with vertical hang.
someone correct me if i am miss informed on temperature and distance. as far as free hang goes. i do it. there is an exponential diminish of light with distance, rather then linear, for this reason and repeated tests, i am sure of increased return with vertical hang.
Probably a foot to 16"
I use 1k bare bulbs and have plants within 8 inches of the bulbs. I suppose it depends on your equipments ability to cool. I pay for lumens, I want to use as many of them as I can. Peace GS
Hood design plays a HUGE role in where your bulbs can be placed. I shoot for 5000 foot candles at the top of my canopy.
hi, thedoo! i run 1k hortilux hps hung vertically. bare in veg and with cooltubes in flower.
in this paper, it was determined that the maximum rate of photosynthesis for cannabis occurs at 1500 umols of photon bombardment.
"Photosynthetic response of Cannabis sativa L. to variations in
photosynthetic photon flux densities, temperature and CO2 conditions
Suman Chandra1, Hemant Lata1, Ikhlas A. Khan1,2 and Mahmoud A. Elsohly1,3
1National Center for Natural Product Research, School of Pharmacy, University of Mississippi, MS-38677, USA.
2Department of Pharmacognosy, University of Mississippi, MS-38677, USA.
3Department of Pharmaceutics, School of Pharmacy, University of Mississippi, University, MS 38677, USA.
ABSTRACT"
i have a quantum meter and with the cool tubes in flower the distance to achieve 1500 umols with a new bulb is 13.5" from the tube or 16.5" from the center of the bulb.
this means there is no reason to run your bulbs closer than this. photoinhibition can result.
the temperature on the leaf surfaces should not exceed 85* F, with 78-80 being better. this can be determined with a laser thermometer from lowes or hd's.
my measurements only apply to my 1k hortilux. if you are using any other bulb they will be different. i imagine that all 1k's would be similar though.
d9
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