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Originally Posted by strictly seedleSs for sure. the lumens are almost doubled betwenn 400w and 600w. My last grow I used a 400w HPS and 8 24w cfls for the side of the grow where the light doesnt penetrate. I then used the same cfls for vegging, and my plants grew sooooo slow, I went out and bought a 40,000 lumen t5 fixture. Now my plants are kicking ass. If you do want to go the HPS way and you can afford a 600w (about $300 for the ballast bulb and hood) and you can control the temp (hps bulbs are HOT) then you will be a happy grower. It's amazing to me how many people rely on lumen output when deciding what kind of lights to buy for growing.
It's not the amount of lumens that helps your plants grow. Lumens mean nothing when it comes to growing plants, since lumens are measurement of VISIBLE light (and plants don't have eyes). Floros put off a lot of usable light, since they emit mostly light in the blue/red spectrum depending on the color rating of the bulb. Plants use light in the blue/red ends of the spectrum, so any other light is wasted.
It doesn't matter how many lumens your bulb puts out, it matters what kind of light it's emitting and whether or not the plants can use it for photosynthesis.
You could have bulbs putting out 6 billion freaking lumens, but if they're emitting yellow, green, or orange spectrum light it's going to be completely useless to the plants.
Quote: chowdan said: Well then i did not mean everyone to freak out. Take a few tokes and shall be all good. No sense in arguing since obviously it doesn't take us anywhere such as the arguments between governments and such.
So onto the subject. Can anyone explain :
Quote: Stoneth said:
And as I said there is still room for improvements with LED's.
As far as lumens my 120 watt LED puts out around 3500 lum, and my 400 watt HPS is around 45 to 50000 lumens. So lumens aren't everything.
If that is the case then really what are the combos that make it grow somewhat decent? Also if lumens are the most important thing what is the bare minimum you need?
I answered this after that quot3e post. Here.v.
Quote: Stoneth said:
Quote: MonsignorBerric said:
Quote: Harry_Ba11sach said:
Quote: MonsignorBerric said: Yipyip It's pretty much all about lumens and the color of the light. For vegetative stage you want mostly blue light, for flowering you want mostly red light. The light is also measured in kelvin (temperature) but I forget what the temps are for each. You can see the red and blue bulbs in the led growing panels.
Oh god this post makes me want to punch everyone in this thread right in the face.
I have to go to bed right now. When I wake up, you can all expect a long ass post with the first actual truth posted in this thread so far except for Stoneth, who also knows his shit.
Lumens
LMAO!!!!!!!!!!!! Woooow........................................................................................................................................................................................................................................................................................................................................................ Why are people getting so pissy here lately? Some people are so arrogant all just because they can grow some bud. If you can't be humble about something you supposedly know so much about I'll have to assume you don't know shit. Please explain how measuring lumens is stupid, how else can you measure light
PAR is another way to measure light. Spectrum seems to be the most important issue imo, then penetration comes into play.
Quote: It doesn't matter how many lumens your bulb puts out, it matters what kind of light it's emitting and whether or not the plants can use it for photosynthesis. You could have bulbs putting out 6 billion freaking lumens, but if they're emitting yellow, green, or orange spectrum light it's going to be completely useless to the plants.
Not true. I first thought this as well, but you are putting out erroneous information. Photon flux density trumps perfect spectrum. Look at the poor spectrum of HPS and then check out the results.
Perfect spectrum will AT MOST yield 35% increase in plant growth. This is easily demonstrated by physics and plant physiology. (Not going into that here.)
What does that mean? It means that a perfect spectrum 650w light of equal efficiency (converts the same amount of electricity into photons) cannot outperform a 1000w HPS no matter what. Now an HPS might have say 20% perfect spectrum and the rest in the weaker absorption bands. In this case it would take about a 780w light of perfect spectrum to equal a 1000w HPS with imperfect spectrum. This is why CMH still trails HPS in overall yield.
Another factors to consider is efficacy, i.e. the ability to turn power into light. The best current white LEDs are on a par with HPS, but with a cost of about $4 per watt.
Then there is light wastage and reflective loss. All lights except LEDs are omnidirectional which equals light loss due to reflection. Reflective losses, light bouncing onto the plants, can be anywhere from 5% to 50% of incident lighting. Light wastage is that which is not reflected and does not fall on the plants.
Light wastage can be minimized by only using the specific light amount needed during a specific stage of the grow (not always possible). I vegged an amazing plant using only a 23w CFL while my buddy was using a 400w MH and performed no better, but wastage was way less.
The other way to prevent wastage is plant arrangement: SOG, scrog, V-stadium all use light better than an uneven canopy or too few plants for the space.
Quote: Also if lumens are the most important thing what is the bare minimum you need?
Minimum lumens cannot be stated alone. It is like giving the size of a piece of paper by saying it is 11" long. You also need the width.
500 lumens of red is way more than 500 lumens of green, not even considering plant physiology.Luemn is not a measurement of energy, but a measurement of how the human eye responds. It takes way more energy for red to appear as bright as green to a human, not so to a plant.
To answer your question: It cannot be answered as phrased.
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