LUMENS? What are they?

Ok, im hearing more and more detailed stuff everytime i get on this sight. What are lumens? What is their purpose for the plants? and How do i tell how many my 400w HPS is putting off?

I'm not sure what exact purpose the lumens have on the plant. I do know that you want to have a certain amount of lumens per square foot to grow a plant properly.

A regular Hps 400 puts out 50,000 lumens. An enhanced spectrum grow bulb like the hortilux, or solarmax, puts out 55,000 lumens.

600w hps puts out 90,000 lumens. lumens are the light aspects that a light puts out (basically lumens determin how bright it is)

Is it pronouced the way it looks?

Lumens are what make your plant grow. More lumens mean more light.

One lumen is the amount of light given off by a candle that hits a 1' x 1' area 1' away from it, thats how it is measured. So more lumens means more light.

loo mens

that help pronunciation?

lol oh ok, well it isnt really worth getting a horilux because thats only like 5000 more, aint much of a change.

so if i put a 600 watt over 3 plants, that means they'd grow faster then the 400 watt hps? if so how much faster?

can someone tell me why posts arent showing up until i post something? like i have to post this message in order to be able to see other peoples posts. it like makes them appear instantly after i post a message.

Now if you cant see posts? How are you going to read my post telling you how you can fix it so you can see them?

skippy pb said:

Lumens are what make your plant grow. More lumens mean more light.

One lumen is the amount of light given off by a candle that hits a 1' x 1' area 1' away from it, thats how it is measured. So more lumens means more light.

Click to expand...

Only partially correct. Both light output AND spectrum are important in making your plants grow. Lumens and Lux are based on the visible light spectrum that the human eye can see. It is a measure of how bright something appears to us. Remember the phrase- 'Lumens are for Humans.'
I come here from the fish and reef aquarium hobby and during that time I have learned a lot about lighting. Coral have a symbiotic relationship with little one-cell plants inside their cells called zooxanthellae. These little guys give the coral energy by utilizing photosynthesis. The thing is, much of the usable light by these algae (as well as terrestial plants) are not in the peak range of what appears bright to the human eye. For example, 2 1000w lamps can output exactly the same total energy accross the visible spectrum, but one lamp will look much dimmer to us. That may be because very high wavelengths toward the blue and violet end as well as the longer wavelenghts in the orange-red end of the spectrum just don't look as bright to us. However, for our plants, what looks bright to us doesn't matter.

More important than lux is PAR level. PAR stands for Photosynthetically Active Radiation. It differs from Lux in that Lux measures light energy mostly in the range our eyes can see (primarily the green range), while PAR measures the entire 400-700 nanometer range, which includes the blue and red ranges most plants and zooxanthellae use for photosynthesis. PAR is just a better estimation of the light energy than Lux, sort of a glorified Lux reading. PAR is measured in microEinsteins (mE). As a reference, full sunlight is about 2000 mE. Another term that is used instead of PAR is PPFD (Photosynthetic Photon Flux Density). These terms are interchangable.

Now with the varying needs of plants during different stages of their life-cycle will obviously require different spectra but you cannot compare bulbs on lumens alone. That Hortilux bulb might put out 'only' 5000 more lumens than a standard bulb, but who cares? There could be a peak in the blue and red spectrums that our eyes aren't very sensitive to, but our plants will 'eat it up' so-to-speak. My guess is the PAR on those Horilux bulbs are significantly better than standard.