Answers about CFL, HPS, How Much Light...

[Indagrojeff]

Although I'm still kind of a new poster, I keep seeing a lot of the same comments--many of which are answered an Dr. Khronik's excellent El Cheapo Guide to Lighting. But there are a few things I'd like to add in regard to watts, lumens, cfl, hps, and efficiency and how much light you need. Maybe this should be stickied?

Watts have nothing to do with light or growth. Watts measure how much power a light fixture uses to produce light. You can tell how efficient a light bulb is by looking at watts. A 23 watt CFL produces as much light as a 100 watt incandescent...even though the incandescent has more watts, it's useless. See what I mean?

What you care about is light...more specifically, light energy. That's what plants use during photosynthesis/growth. Light is measured in lumens. In my experience and reading, lumen amounts per sq. ft./sq. m. look like this

2000 lumens sq. ft./21500 lumens sq. m. = Absolute minimum for growth. You won't get much from this, especially after the plant has grown a bit. Not really enough to flower well.

3000 lumens sq. ft./32250 lumens sq. m. = Pretty Good growth. Enough light for the entire light cycle, although your yields may be lower.
4000 lumens sq. ft./43000 lumens sq. m. = Very good growth. Once you pass around 3500, growth rate and ability goes up fast.

Over 5000 lumens sq. ft./53750 lumens sq. m. = Optimal growth. Dense growth in all stages.

Keep in mind that using reflectors, using mylar or having flat white walls, and keeping your lights close to your plants keep you from wasting lumens. It's not just about having light, it's about getting the light to your plants. IMO, people ofter overbuy lights. This creates more light, but the light isn't always hitting the plants. And that creates more heat and ventilation issues, which causes stress problems.

That's why it's still impossible to tell anything about growth or yield based on just lumens. A guy that has an HPS that is too far away from plants that have no walls near them and no ventilation may get poorer results than a grower with CFLs that uses reflectors and has a couple of lights under the canopy in a well-ventilated spot.

HPS lights are often said to generate more heat than CFLs. That's not really true...it's just that they are more efficient at producing light, and there's a smaller surface area on the bulb itself for the resulting heat to dissipate. That means more ventilation. But the higher amount of lumens per watt means you use less power and get greater light penetration through your canopy. Still, I'm a believer that well used CFL's can give you great grows with less ventilation and heat issues. If you're in a small to very small area (less than 4 sq. ft./.25 sq. m.), I'd consider the advantages of CFLs in that way.

But HPS is more efficient. A typical 250 watt HPS bulb/unit will produce about 27,000 lumens. I've seen people use a 250w in a 3' x 3' room and get good results. That's 9 sq. ft. which = 3000 lumens a sq. ft. (Really, a 250w HPS is better in a smaller area.) to give you an idea of the difference in efficiency of CFL vs. HPS, think of this.

23w CFL = 1600 lumens = 69.6 lumens/watt
30w CFL = 2000 lumens = 66.7 lumens/watt
40w CFL = 2600 lumens = 66.3 lumens/watt

compared to

150w HPS = 14000 lumens = 93.3 lumens/watt
250w HPS = 28000 lumens = 112 lumens/watt
400w HPS = 50000 lumens = 125 lumens/watt
600w HPS = 90000 lumens = 150 lumens/watt

So you can see that HPS is more efficient than CFL...and as you get into bigger HPS bulbs, it becomes a lot more efficient. There's also fewer hassles with multiple cords and saved money on your energy bill. If you've got a big area and/or you can deal with the heat and ventilation, HPS is the way to go in flowering. Still, I'm a believer in small HPS lights and combo HPS/CFL grows...if you've got a 2' x 2' room, you can use a 150w HPS and 4 23w CFLs from Wal-Mart and get a terrific grow with very few heat issues.

Hope this helps some people. And, yes, I wrote it all.

This is my very first post on a forum, anywhere! And your having written it all has motivated me to do so. Please forgive me if I don't follow all of the protocols but I am a quick study.

The reason I set up with this board is because one of our customers just emailed this thread to me and I thought I'd throw in with my observations as it relates to an important facet of our overall thermal management designs on the drivers which power our induction grow lamp products.

The post you've made is well written and compares two conventional grow lamp types. However I believe there are some inaccuracies in that the values posted were for initial HPS lumens rather than mean lumens which would be a better value to use as it better reflects the output over the lamp life. I've attached a link to the chart values we like to use. In respect to the efficiency getting better as the lamp gets larger, this is true up to 600 Watts, but then the efficiency decreases as you go to 750 watts and 1000 watts. Both Metal Halide and Induction lamps continue to get more efficient as they bet bigger and do not show this backward bending affect on efficiency values as HPS does.

Inda-GRO

My 30 year background is that of an Electrical Engineer with experience in nuclear and product development design engineering. Over the last year I've been working on the Inda-Gro design team and find this exciting, because so much of it stems from work that was brought to the industry by one of the most inspirational inventors of all time and that is Tesla himself.

Of course I'd like to make more people aware of the advantages of utilizing induction grow light technology I'm not here to promote Inda-Gro products as the sole solution for your particular needs since there are, from what I'm learning, many reasons that would influence the lamp choice that a grower may decide to use.

While not being a botanist by training or trade I was excited to get involved with the electrodeless induction light technology for the grower since it relies on relatively simple but delivers a high lumen/ low wattage solution for those species that demand not only proper spectrums but 1,500-1,800 micromoles saturation at the receptors to best simulate the natures energy and wavelengths.

Please feel free to call me or call me at the office should you wish to discuss anything that warrants our followup.

Thank you for your time, Jeff

[jon420]

I have a few interesting data points for cfl and fl bulb fans. After reading some cfl grow threads where the plants suffered from burning if the bulb is too close to the plant, I decided to measure some bulb temps directly. Using a good quality surface pyrometer on stabilized bulbs (on for about an hour), I get 84 degrees F for a 34w 4100k 48" T12, and 104 F for a 14w "soft white" cfl. I guess I now understand why a T12 can be dropped right down into physical contact with the tops of the plant without causing burn, and why any cfl must be kept several inches from the nearest leaves.

The T12 3000K burns too. It took all day but it did burn. Juat wanted to throow that out there. Never had a T12 6500K burn though. Great test too!!!

[mickey9987]

Heres my grow any tips
YouTube - Mini Update.1.8.2011 The Seeds

[bushmuncher]

Is it ok to hve a reptile light using a sun Glo 150w bulb It is a Neodymium spot lamp and I have two other lispot kigts reflecting off foil also.

Who cares where I got the info. the fact is that I have done lots of homework when it comes to lighting like you. Most peeps just look at lumens "hey isn't this light bright, man I have to ware sun glasses!" and off they go to the races. We all know, well maybe not, that like you said in your first post (Still, I'm a believer in small HPS lights and combo HPS/CFL grows), dual spectrum works best for the entire grow. If you can't find out the par watts, call any manufacturer and they will tell you after a few forwards-it's not hard, just takes some effort, and not just searching these boards where 90 percent of the answers are: mh for veg, hps for flower-and get the most lumens-not!. I use to grow mh during veg and hps during flower. I use to go by lumens only but could not understand why my grows did not get any better/bigger when I went with the fancy/overpriced high lumen bulbs. Hmmmmm, I wonder why.
Anyhoo, yes I'm a firm believer of the KISS method, and there are plenty of great grows where people just look at lumens. Hell, my ave. yield under a 1000 watt bulb was around 34 oz's, and lumens was all I looked at. First time I went dual (600,400), same strain from clone-38 oz's and the plants were much healthier.
Here's a pretty good site-kind of old: Grow Marijuana FAQ, Cannabis cultivation - marijuana growing tips & photos
And the best damn 400 watt bulb on the mrkt. Phlips MasterColor Ceramic Metal Halide ~ CMH ~ HPS-Retro White
Peace and good luck to all.

[flyinhi66]

hey i just started 5 seedlings,they've been unger a 18watt under cabinet flu light 4 10days, ? how long should I wait to put them under a 250w mh, also would it be benefical to add a 230 watt hps conversion lamp on during veg state? been growing outdoors 4 yrs, my 1st time indoors,i purchased a 3x3x6 grow hut & have like 10 250mh & 15 175 watters. :stoned:

[massbud]

what you think of my setup do you think its good or do you think it needs more light?Attachment 273119Attachment 273120

[jimbobalong]

roughrider- only new to growing ventilation is ok its just the lights that have got me. I have a 250w clf for veging and a 600w hps for flowering is the 600w to much for a 2x2 grow room.how far away should i keep the cfl from the top of seedlings??

[mak14317]

very goos posts to read..........

[Jungl3Jim]

A very good post when it comes to comparing CFL to HID in terms of Lumens and such but, plants "see" light differently than human beings do. As a result, lumens, lux or foot-candles should not be used to measure light for plant growth since they are measures used for human visibility. More correct measures for plants are PAR watts, PPF PAR and YPF PAR, although each in itself does not tell the whole story. In addition to quantity of light, considerations of quality are important, since plants use energy in different parts of the spectrum for critical processes.
Plants are sensitive to a similar portion of the spectrum as is the human eye. This portion of the light spectrum is referred to as photo synthetically active radiation or PAR, namely about 400 to 700 nanometers in wavelength. Nevertheless, plant response within this region is very different from that of humans.
The human eye has a peak sensitivity in the yellow-green region, around 550 nanometers. This is the "optic yellow" color used for highly visible signs and objects. Plants, on the other hand, respond more effectively to red light and to blue light, the peak being in the red region at around 630 nanometers.
Red light provides the most efficient food for plants. However, a plant illuminated only with red or orange light will fail to develop sufficient bulk. Leafy growth (vegetative growth) and bulk also require blue light. Many other complex processes are triggered by light required from different regions of the spectrum. The correct portion of the spectrum varies from species to species. However, the quantity of light needed for plant growth and health can be measured, assuming that all portions of the spectrum are adequately covered. Light for plants cannot, however, be measured with the same standards used to measure light for humans.
First, how do we measure light quantity for humans? The obvious way is based on how bright the source appears and how "well" the eye sees under the light. Since the human eye is particularly sensitive to yellow light, more weight is given to the yellow region of the spectrum and the contributions from blue and red light are largely discounted. This is the basis for rating the total amount of light emitted by a source in lumens.
The light emitted from the source is then distributed over the area to be illuminated. The illumination is measured in "lux", a measurement of how many lumens falls on each square meter of surface. An illumination of 1000 lux implies that 1000 lumens are falling on each square meter of surface. Similarly, "foot-candles" is the term for the measure of how many lumens are falling on each square foot of surface.
Clearly, both lumens and lux (or foot-candles) refer specifically to human vision and not to the way plants see light.
How then should the rating for plant lighting be accomplished? There are two basic approaches to develop this rating: measuring energy or counting photons.
PAR Watts for Plants
Watts is an objective measure of energy being used or emitted by a lamp each second. Energy itself is measured in joules, and 1 joule per second is called a watt. A 100 watt incandescent bulb uses up 100 joules of electrical energy every second. How much light energy is it generating? About 6 joules per second or 6 watts, but the efficiency of the lamp is only 6%, a rather dismal number. The rest of the energy is dissipated mainly as heat. Modern discharge lamps like high pressure sodium (HPS) and metal halide convert (typically) 30% to 40% of the electrical energy into light. They are significantly more efficient than incandescent bulbs.
Since plants use energy between 400 and 700 nanometers and light in this region is called Photo synthetically Active Radiation or PAR, we could measure the total amount of energy emitted per second in this region and call it PAR watts. This is an objective measure in contrast to lumens which is a subjective measure since it is based on the response of the subjects (humans). A PAR watt directly indicates how much light energy is available for plants to use in photosynthesis.
The output of a 400 watt incandescent bulb is about 25 watts of light, a 400 watt metal halide bulb emits about 140 watts of light. If PAR is considered to correspond more or less to the visible region, then a 400 watt metal halide lamp provides about 140 watts of PAR. A 400 watt HPS lamps has less PAR, typically 120 to 128 watts, but because the light is yellow it is rated at higher lumens (for the human eye).
Since plant response does "spill out" beyond the 400 nanometer and 700 nanometer boundaries, some researchers refer to the 350 â?? 750 nanometer region as the PAR region. Using this expanded region will lead to mildly inflated PAR ratings compared to the more conservative approach in this discussion. However, the difference is small.
While HPS and incandescent lamps are fixed in their spectral output, metal halide lamps are available in a broad range of color temperatures and spectral outputs. With this in mind, the discriminating grower can choose a lamp that provides the best spectral output for his specific needs.

Hey all..
hate to drag up an old post but this has been pilfered directly from here.. albeit great info.. but still
What Are PAR Watts? - Sunmaster is proud to publish PAR Watt information

[bubbels]

hey i use a son-t pia green power 600w and i dont know how old they are. so what can i do to measure my ligth power.? will a lux meter do.?