Watts or Lumens Per Sq/Ft.. ?

[green_thumb...]

soooo? im confused by all these numbers and that's not normal cuz im a machinist and have to deal with a great deal of formulas n shiz, so is it 105 or 15 or what? also I have this 600 temporarily so i have to get a new light and one of my buddys has a 1000w that needs an ignitor and thats cheaper than a whole new set up but id like to get the lumatek dual 600w for it if i can slang my truck i can get it

 

[00420]

it's 99.38 OR same as 3 4 x 8 ebb & flow trays....... how ever u wanna look at it...

if your going to go with a 1k in a 4.5 dia i would think about a cool tube and a big ass fan the cost of that would be the same as a 600

im running 2 1k's in cool tubes 8" canfan @ 6' it leaves me about 2'-2.5' of grow space 6" is root zone then a plant about 1.5-2' any closer and they burn
i belive im at 89sqft & 24 or 25wpsqft and pull 2-3lb's per light i will not lie my bud's are not as dence as i'd like them to be but Y & Q are there i been thinking of tossing a 3rd 1k or a 400 cmh in there but have not done it yet

 

[Pig-Pen]

it's 99.38 OR same as 3 4 x 8 ebb & flow trays....... how ever u wanna look at it...

if your going to go with a 1k in a 4.5 dia i would think about a cool tube and a big ass fan the cost of that would be the same as a 600

im running 2 1k's in cool tubes 8" canfan @ 6' it leaves me about 2'-2.5' of grow space 6" is root zone then a plant about 1.5-2' any closer and they burn
i belive im at 89sqft & 24 or 25wpsqft and pull 2-3lb's per light i will not lie my bud's are not as dence as i'd like them to be but Y & Q are there i been thinking of tossing a 3rd 1k or a 400 cmh in there but have not done it yet

Holy God, nevermind...lol...I just realized were talking about two different things here....I was thinking floor space, but you guys are talking vertical area of a cylinder. .

You are correct then, How embarrassing.

 

[green_thumb...]

Thanks guys, i was planing to get a cool tube for it i might have to settel for a 600 tho 1000 really expensive

 

[Hammerhead]

I'm using 2 600 hortilux hps in a 8x10 room. I use 1 of them for Indica Phenos the other 1 is for Sativa so my lights are staggered one is lower then the other.

 

[Joe Hawkins]

i get 1g per watt at 30watts per square foot

 

[T.Baggins]

I hear lumens are a measurement for the human eye and have nothing at all to do with plants. With plants, it’s about incident energy and the light that can reach the leaf that the plant can actually use for photosynthesis. That can be measured in watts per meter squared, or in foot-candles of incident energy..

 

[green_thumb...]

well this is my terrarium as it sits now with the 600w my buddy is gonna hook me up with a 1000w at the end of the month

I might be shooting too high but i hope to get a lb of meds from this

 

[igrowwitmatches]

either will work but.... lumens dont really matter to the plant... neither do watts... its just a general way to judge

 

[Hammerhead]

PAR / QUANTUM LIGHT (400-700nm)
The light that drives photosynthesis in plants is Photosynthetically Active Radiation, or
PAR light. This is also referred to as Quantum light, because it is measured in units
of moles striking an area over time. Though PAR light ranges from 400 to 700nm, the
region brightest to human eyes is the area of least effect on plants. Measuring quantum
light can tell you if your plants are getting a suffi cient amount of usable light.

 

[guest 77721]

Watts are important because it represents the total amount of energy in the form of heat and light produces. Watts are more useful for sizing the ventilation system and setting up a working cabinet.

Lumens are actual light output as well as spectrums which are usefull for picking one bulb or manufacturer over the other.

 

[purpledomgoddes]

http://www.icmag.com/ic/showthread.php?t=109201
figuring watts per square foot in a vertical system

http://www.icmag.com/ic/showthread.php?t=108993
lighting conversion data

lighting discussed in these threads.

sunlight is ~450 par watts. 1k @ 1 ft=~150-300 par watts/5k lumens/50k lux.

leaves max out @ ~300 par watts. mix in uvb+flouro+party lights for full spectral influence of nature. mimic aurora borealis, cloud cover, etc. all send electro-chem signal, that initiate hormones, etc.

intensity(watts) generally good, while spectral array of light better(mixed mh+hps+uvb+flouro,etc).

1k's @ 2-6" away from vertical canopy. get as close as possible to achieve saturation point. good air flow+.

hope this helps! enjoy your garden.

 

[MtnKuSh]

some good posts in this thread.. keepit coming

 

[whodair]

a lot depends on your environment. i yeild more w my 430w than my friend w 600w. we have the same size area, i have more height. more height=more air in the room. i need less ventilation and have better temps and humidity. he has to rush air through his room quickly to keep it cool, which causes some cupping of leaves because of drying effect.

i tried a 600 and went right back to my 430. 58000 lumens is better yielding than 90000 lumens in this case.

 

[MtnKuSh]

 

[CobblerJack]

i have always went by watts per sq/ft but always read people saying lumens per sq/ft.. what do you go by?

Your poll is actually a trick question. Without saying what you would use the watt or lumen per sq ft number for, it's impossible to tell if you're asking this because you want to use it to discover something about plant growth or about electric usage. The tricky part is that many people go by both watts & lumens at any given time, depending on which aspect of garden illumination they are most interested in at the moment - light output or energy input.

Lumens are the grow-power that fuel plant growth and yield; watts are the electric-power that fuel utility bills and heat. You cannot use watts to grow plants without first converting them to lumens, and every lamp converts watts to lumens at a different rate. Unfortunately, many growers cling to the hardware store mentality they used before they developed an interest in growing. It essentially says, "40 watt light bulbs supply twice as much light as 20 watt bulbs". The end result is that many growers still use the watt as a lazy man's measure for light.

Given that 1 watt can generate as little as 35 lumens from one lamp and as much as 150 lumens from another, this mentality doesn't serve a diverse body of growers very well at all. Diverse meaning the mix of growers you find on a forum like this, who each could be lighting their garden with fluoros or MH or HPS of all different wattages - and with each lamp converting watts to lumens at a different rate.

When a grower using the hardware store mentality sees the results from a garden that used 70w/sq ft for example, he presumes he can grow the same results/sq ft given the same watts/sq ft. The big problem with this is the mistaken belief that there's never a difference between the lamps from which the watts per sq ft are being calculated, or that the difference is trivial enough to be ignored. If we all used the exact same lamp this wouldn't be an issue, but the reality is that people who frequent forums like this use many different types and wattages of lamps that can deliver surprisingly different amounts of light (grow power) per watt.

For example, at 70w/sq ft a 1000w HPS delivering 150 lumens per watt is generating 10.5 kilolumens/sq ft of grow-power (10,500 lumens). A grower using a 70w MH that's delivering 71 lumens per watt over 1 sq ft, would generate only 5.0 kilolumens/sq ft of grow-power. Same 70w/sq ft of electrical power, but less than half the grow power.

I know it's not the intent of growers to mislead other growers, but indirectly that's what's happening. Using watts as a measure for light surreptitiously discriminates against growers who use a lesser wattage lamp as well as those who don't use HPS. Both cases handicap a grower with fewer lumens per watt. In the case of this 70w MH grower, he is disadvantaged on both counts (smaller wattage lamp + MH), and because of that will end up being very disappointed with his results compared to the other grower's, in spite of matching his 70w/sq ft. With regard to plant growth, he would have been much better served using lumens/sq ft than watts. After all, lumens is the de facto standard measure for available light. And as this example illustrates, the differences are not trivial. They can be off to the tune of 100%+ depending on the lamps in question, and can lead one to believe he's packing a lot more grow power than he actually has.

Because of the tricky nature of this poll's question, I suspect that the votes for watts/sq ft are split between two types of growers - those who use it correctly as a measure of electric power, and those who use it incorrectly as a lazy man's measure of light or grow power. The votes for lumens/sq ft are of course speaking directly to grow power. Having said that, I think the larger majority of total votes are from growers who are more interested in grow power, so my vote goes to lumens/sq ft though I would have gladly ticked off both had I been able.

The bottom line is that we shouldn't have had to choose between one or the other because both serve a useful purpose when each is used correctly, but not the same purpose as this poll suggests.

If you're more interested in how energy is being used, choose watts.

If you're more interested in how light is being used, choose lumens.

Same goes if your interest is in examining efficiency or yield. gram/square foot, gram/kilolumen, gram/watt, they each serve three different aspects of growing - space, light, energy.

That's what I go by.

Regards

 

[Cythas]

Here you go, read this please its really helped me out with my light situation with height from tops and with saturation into my canopy.

http://www.420magazine.com/forums/grow-lighting/201541-lux-lumens-par-etc.html