Time to put lumens to rest....

3

3 Pounds of Weeden

Active Member
I'm no expert on cannabis cultivation by any means, but there are some things I see going around this site and I think it would be best to finally put the right information up here.

Lumens and watts are not the same. Lumens are what is perceived by the human eye. NOT plants. Plants go by the nanometer spectrum in which they use 2 different kinds of Chlorophyll (A and B) to produce photosynthesis.



So, when you hear someone talk about lumens, ignore them. Our eyes are not involved in photosynthesis. Here's an in-depth article on the matter.

http://www.ecse.rpi.edu/~schubert/Light-Emitting-Diodes-dot-org/Sample-Chapter.pdf Page 278
 
haulinbass

haulinbass

Well-Known Member
Its all about the PAR light but intensity makes a huge diffrence indoors, just sucks there doesnt seem to be an affordable ballance between the two, yet
 
F

fg2020

Active Member
Lumens and watts are not the same? Well no shit, some lights are more efficient than others and produce more lumens per watt. Plants use that light which is found in the visible spectrum, the same spectrum visible to your eyeballs. You want to get some decent yield then throw your charts in the garbage and get some HPS lighting.
 
NEONKINEBUDZ

NEONKINEBUDZ

Active Member
Common info, should be common knowledge. It's nice to see someone do some research. The problem is, lumens are how the manufacturer rates the bulbs. So...unless every person that uses HIDs were to buy a PAR meter and test every possible bulb with every possible ballast combo...they will continue to use lumens...
 
topfuel29

topfuel29

Well-Known Member
3 Pounds of Weeden said:
So, when you hear someone talk about lumens, ignore them. Our eyes are not involved in photosynthesis.
Click to expand...
"Plants use light energy between 400 and 700 nanometers, the region known as Photosynthetically Active Radiation or PAR.Illumination for plants, also known as "irradiance", is sometimes measured in PAR watts per square meter (W/m2). Another means of measuring light quantity for plant growth involves discrete units of quantum flux in the PAR region called "photons". Photon flux is commonly measured in units of micromoles per square meter per second (µmoles/m2/s), where 1 mole of photons = 6.022 x 1023 photons.

This is an objective measure since it directly indicates how much light energy is available for plants to use in photosynthesis. However, lamp manufacturers typically rate their lamps in lumens, a measure of light in the spectrum visible to humans. Moreover, most lighting engineers measure lighting levels in lumens per square meter (lux) or per square foot (foot-candles). Since the spectral sensitivities of plants and humans are quite different, there is no direct method of converting the units without evaluating the full range of spectral characteristics for a given light source."

Every bulb I ever bought had the lumens on the side of the box.
when you buy a bulb a good PAR value is already engineered into the bulb. (horticultural)
(Usually)the chart on the side of the box tells you what nanometers the lights engineered at, to get you optimal photosynthesis A, and B.
write every horticultural bulb manufacturer, tell them there wrong to put lumens on the side of there box.
 
3

3 Pounds of Weeden

Active Member
fg2020 said:
Lumens and watts are not the same? Well no shit, some lights are more efficient than others and produce more lumens per watt. Plants use that light which is found in the visible spectrum, the same spectrum visible to your eyeballs. You want to get some decent yield then throw your charts in the garbage and get some HPS lighting.
Click to expand...

Who said anything about yield? you can have all the efficient light you want; doesn't mean it's the right light. The purpose of this thread was to let noobs know they don't need to worry about lumen when a lot of people will clearly tell them that. You clearly have never used a T5 ( or even the right bulbs if you have) so, throw yourself in the garbage.
 
3

3 Pounds of Weeden

Active Member
You can have a bulb that is a million lumen, but if any of that light is yellow or green, it's being wasted in your grow room. And so what if a manufacturer puts the lumen on the box?

All i'm saying is that: I see so many noobs on here asking questions and they always get something like "you need x amount of lumens" which is wrong no matter how you argue it, it shouldn't be judged off of lumen, just watts and the nanometer spectrum you are on
 
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