Thanks for showing this link. It shows GE K&B lamp to be just about as good, and it's a much cheaper lamp. Almost everywhere I read scientific articles using warm white (3000K) for their gardens. K&B is a very high lumen lamp, 3300 or 3400, I can't exactly remember. I think for growing indoors for a month I would use K&B. Since I live up north we have a much longer indoor season, and I grow roses etc, I set up and indoor T8
garden and I wired it for optional "overdriven" by mounting an extra ballast in each fixture, with a toggle switch on the end to control the overdrive. High output T8 lamps put out 3100 lumens normally driven, and maybe 5000 lumens overdriven. You may go onto ebay and look up jslighting for some salvaged T8 ballasts, you can get them sometimes for $25-35
per 10 + shipping depending on who's bidding. You may also see my garden pictures on the flickr site. My son grew peppermint and bergamot - the growth was phenomenal, the bergamot had huge colas, it looked just like a cannabis plant, and the peppermint was lush proliferating like mad, with tons of runners and rhizome production.
Paul Mozarowski.

Here is a link that might be useful: My garden with Phillips HO 3000K T8, 2$ lamps overdriven to 5000 lumens.

Also you could also look into the USHIO line of lamps, they are also excellent, I used to use them until I found the
TCP Phillips HO T8. Ushio has some very nice high CRI lamps, with high lumens and extremely long life. Some very old Canadian government research shows that with fluorescent lamps lumen output is the single most important factor in plant growth, and regular lamps outperformed the specialty lamps. I am very big on T8's now, because the lamp is skinny and does not block the reflected light the way a T12 lamp does. With a T12 lamp, the light gets trapped in the fixture behing the lamp and can't get out. I have compared the lumens with my new garden of T8's and my old setup with packed T12 strips, T12 at 50W per square foot, and T8 at 30W per square foot, and the intensity is 50% higher in the T8 garden, even with less power. Overdriven, and the T8's just blow away the T12, with over
2x the light intensity on a digital meter. However, if you're only using the garden for a month, I would not put in the extra work to modify the fixture, unless you're a real lighting nut like me and you enjoy doing these projects for a hobby. I even lined the reflectors with mylar to maximize the total incident light. Paul Mozarowski.

Here is a link that might be useful: Direct link to comparison of various lamps from thread starter.

The K&B tube is a warm white, I think? I've had very poor results from them, except for very young seedlings, but then I wasn't growing Zinnias :)

Paul, that's quite a light show that you have set up but don't eat the mushroom.

I live up north too but after a month under lights I plan to put the seedlings out in a little portable greenhouse during the day and bring them in at night.

I am more interested in the plant and aquarium lights becasue they are so cheap compared to the ott and other full spectrum lights. However, as I said I don't know if the comparison test was completely impartial. If anybody knows anything about the GE plant and aquarium lights please post.

Hi, I am quite certain that when I started growing about 6 years ago, there was research from the Canadian Govt dept of agriculture or possibly a Canadian university comparing the growth with different lamps. Their conclusion was not to waste money on fancy lamps, because they achieved their best growth simply with the lamp that provided the most lumens, in their case this was just a cool white lamp. I remember this extremely clearly, but I cannot find reference to this on my google search today. Although I did not verify this for myself, these people have already done the work for me.
Unfortunately I cannot find the link for you. The theoretical basis for these specialty lamps is the absorption characteristics of ISOLATED CHLOROPHYLL, with peaks in the blue and red, and trough in the yellow green range, leading people to ignorantly state "that the yellow and green light is wasted", but better more modern research shows that yellow and green light is actually BETTER for the plant than blue, and red is the absolute best.
Nice lighting spectrum site:
http://www.cs.cmu.edu/~zhuxj/astro/html/spectrometer.html

Ah! Good! Here it is -- please study the phosynthesis action spectrum very closely -- it is NOT THE SAME as the chlorophyll absorption curve because the plant has developed molecules to USE ALL WAVELENGTHS EQUALLY WELL: pleas follow the link, and discard any ideas you may have of making the lamp manufacturer's profit go up, and at the same time needlessly depleting you own pocket!!! I have seen similar graphs for other plants other than alga, but I just can't find them today. I definitely was able to find them five years ago, but unfortunately things disappear from the internet, it is not a permanent archive.
Paul Mozarowski.

Here is a link that might be useful: Photosynthesis action spectrum

I should have given my last post a different title. Plant and aquarium lights just increase the manufacturer's profit and deplete your bank account, but they won't grow as well as standard cool white. Please compare the line output from just a cool white fluorescent and with the photosynthesis action spectrum discovered by the studies of scientists and botanists. P and A lamps are bogus, they only interact with chlorophyll, not the abundant carotenoids etc., their lumen output is very low, and PLANTS CONVERT A PHOTON TO A HIGH ENERGY ELECTRON, NO MATTER WHAT THE WAVELENGTH, so just look for a lamp that has MAXIMUM LUMENS, such as K&B, or better yet 3000 - 3500K high output T8, available from Phillips, and cost $2 per lamp from businesslights.com Absolutely DO NOT BUY the plant and aquarium - less photons = less high energy electrons = less growth.
Paul Mozarowski.

Here is a link that might be useful: Photosynthesis action spectrum

Be careful not to oversimplify. One red lumen (630nm) contains approximately four times as many photons as one green lumen (530nm). Lumen comparisons are valid for sources at the same wavelength but only approximate for the various white light sources, and not at all valid for light sources at very different wavelengths.

Whenever you make an absolute statement you are making a false statement :)

Even the basis of the OP growth comparison needs to be questioned. Are the largest greenest leaves what you want? Perhaps, but my experience (with cacti and succulents) is that warm white fluorescents produce lots of lush growth which rapidly becomes too weak to stand up under its own weight. In such cases, more blue light should be added to the mix to increase the strength of the plants. Where only plant mass matters then sheer numbers of photons at the red end of the spectrum will meet your needs although the plants will not be ornamentally attractive or strong. HPS lights achieve this, and even LPS lights achieve the best yield for some crops.

Thanks, I thought of that after I posted it, lumens has something to do with the human eye sensitivity. It would be most interesting to normalize the spectral output of the various fluorescent line output, and show it as photons vs colour (frequency). Possibly then adding a metal halide
to 2 HPS lamps makes sense based on what you say. I do have a case of 5000K T8's, I'll mix them in with my 3000K
and observe. Right now I notice the foliage is quite red, and
the peppermint is somewhat purple. I will see if putting 50:50 5000K and 3000K makes a difference, and compare with pure 5000K. thanks for the pointer, Paul Mozarowski.

A technique used by some commercial growers is to use HPS lighting simply because it produces so much light, and then to add a few actinic fluorescents to stop the plants etiolating too much. Sometimes they don't mind the etiolation because they are growing a food crop, or they don't get it because they have enough natural light to counteract the etiolation, or simply because their crops grows well under just HPS.

The conversion of various fluorescent, and HID, lumen outputs into relative photon fluxes has been done by some people for some lights. I'll give one link which is now rather old. The basic physics is still valid and so it makes an interesting read although most of the lights included are now obsolete. I've also seen tables that provide an approximate "correction factor" for different classes of lighting technology to convert lumens approximately to a photon flux. Basically all the white light sources are fairly close to eachother, HPS is a bit out there, and non-white sources are wildly off.

Here is a link that might be useful: An attempt to move beyond lumens

Interesting, they show the number one lamp to be the phillips adv850.
I'm using the adv830. Looks like I need to order a few cases of the adv850. Actually I do have a case of the Ushio 5000K which would probably be very close to the phillips.

Based on that link, I just swapped out all of my Phillips 830 and replaced them with Ushio 850, because I don't have any of the Phillips adv850 in my stock. That will be my next order from businesslights, and I'll see if they will accept a return on my unused case of adv830's. I studied the spectral output and compared it to the photosynthesis action curve, and I just thought the 830 was a better match. I wonder, they didn't actually test the adv830, and if it is such a significant difference. Oh well, I'll observe my plant growth and send a report. Paul Mozarowski.

The test is several years old, possibly the adv830 didn't even exist then. And of course they didn't test every existing fluorescent, just a selection of the ones more commonly used on plants. It helps to know the basic phosphor types because out of all the dozens and dozens of different branded fluorescents, there are really only a handful of common phosphor combinations plus a handful more specialist phosphor mixes, most of these combinations are represented.

The tests are entirely theoretical, you might want to observe plants under both tubes and see if there really is a difference. Factors such as the red/blue rations will be far more important for some plants than others, and the weighting to calculate PUR will be different for different types of plant (because every plant has a different photosynthesis action spectrum, even the same plant grown in different lighting conditions), so results may vary.

I've had my roses for 24 hours under the Ushio 850, I suspect the phosphors are probably almost identical to the adv830,
and I've notice ... drum roll ... the leaves on one of my mature potted rose cutting bush is absolutely greener. It started out a yellowish reddish pale green and it's going into
an obviously darker shade of green. My hydrofarm shows the same number of foot candles coming off the Ushio850 and the
Phillips ADV830. The immature cuttings are not growing fast enough to report anything as of yet. Thanks for finding this chart!!! Paul Mozarowski.

I've read and reread recommendations for the best combination of florescents to promote the growth of tom and pepper seedlings. I was heavily infuenced by the results shown on wayneScmidt's site that was originally referenced above. As they say a picture is worth a thousand words and in that test, the ge plant and aq won leaves up. It's also interesting, as object16 pointed out, that the kitchen and bath finished a close second especially because it was not a so called plant light.

I will in all liklihood go with 3 ge plant and aq for best growth qualities and 1 kitchen and bath to enhance brightness (lumens) and to capitalize on whatever else that caused a second place finish in the comparison test. Last but not least, I am impressed that that the pl and aq cost only $5.97 at walmart compared to $6.84 for kit and bath. The ott and phillips plant lights cost $10 at homedepot.

I have copied an excerpt from an interesting post that I read on another site below that convinced me to add the 1 flo for lumens.

"I put a
couple of the "Plant and Aquariums" (40W) above a newly set up 55G and
the tank really looked dim. They have so much energy nearly out of the
visible spectrum that they need a *lot* of Watts for comfortable viewing
(i.e., to get the lumens up). Otherwise, they look to me to be pretty
white, but just a tad magenta or purplish in color.

I added one "cool white" and it was as if I had quadrupled the
illumination. The tank has a lot of irridescent fish, and the plants and
fish just became dazzling.

The "P/A" tubes probably provide plenty of plant energy, and the "cool
white" lots of viewing light. The trick is to get a nice balance that
grows plants and also looks good. Since plants and eyes have different
response spectra, I always seem to be happier mixing different tubes to
get the results I want."

That's a good deal for P&A, I'm used to seeing it priced $15-20, which is ridiculous. On account of the huge garden size that I'm planning to have, I may actually run a similar experiment myself, except that my garden is only T8. I may try it out with peppers. What strain of peppers are you planning on growing? Paul Mozarowski.

the Ushio 850, I suspect the phosphors are probably almost identical to the adv830

The Ushio 850 is, I assume the Ultra8 branded F32T8? Here is the datasheet for you to check, it includes spectral charts. This is a standard high-spec (long life, excellent lumen maintenance, high lumen efficiency) triphosphor spectrum.

Similarly, the Philips ADV830 is a high-spec triphosphor tube. The spectral emissions will be almost identical to the Ushio except the red spike will be slightly higher and the blue spike low to produce the 3000K colour temperature.

All 800 series tubes of this type have essentially the same spectrum made up of the three dominant spikes in red, green, and blue. This makes it somewhat pointless mixing tubes of different colour temperatures, you are not achieving a fuller spectrum as some people assume, just exactly the same spectrum at an intermediate colour temperature.

Growing peppers big time. Mostly chile- jalepeno, portugal, cayenne and chimayo. For regular peppers, I like the chocolate pepper that matures from green to choc. It takes away a little of the green taste.

reply to shrubs n bulbs : precisely, there is no point in mixing cool and warm to get "complete spectrum", they are just different formulations of the same three phosphors. It seemed to me that the 830 matched the photosynthesis action spectrum the best, a stronger red peak to really interact well with the
strong chlorophyll absorption in that color. I'll need to do studies with seedlings exposed to 850 vs 830, and when I get to it, I'll start a new thread.

This might take a while, because I don't have all three gardens going yet.

In the meantime, I've turned the overdrive off, because I don't think my cuttings are ready for it yet. The foliage seems to have "relaxed" a bit, leaves opening up nicely, but new growth is still quite red looking. I'll observe to see how quickly the transition from red to green takes place. Paul Mozarowski.

Hey folks; just joined member here.

object16, Thanks the link you gave Sun, Dec 9, 07
"Here is a link that might be useful: An attempt to move beyond lumens ; http://www.aquabotanic.com/lightcompare.htm";

That article is technically dense but worth several rereads. Best assimilation of plant lighting principles I've read so far. Would love to see something as rigorous done for non-aquatic plant lights and of course as up up todate as possible. Would have liked to see how ceramic metal halide bulbs compared.

BTW, as soon as I finish posting this I'm gonna post a new thread asking for info on the 600W Sun Pulse Metal Halide Retro grow lamp series. Anybody, hit me up there if you know anything. Thanks

Follow up of my own observation: I was growing rooted cuttings with 3000K Phillips 830. Many of the cuttings were developing yellow foliage, I didn't know if that was because of too intense a light, or wrong light color, not enough blue for proper chlorophyll synthesis. I noticed another bid rooted cuttings under K&B showing not very dark green, kind of pale green foliage. I've thrown in 50:50 mix of Ushio 5000K and Phillips 830, and I noticed within a few days new foliage showing more dark green color, old pale leaves shrivelling up and falling off, I do believe that it may be better to have a better balance of light with for example a 3500K or 4100K lamp. It seems as if there is no disadvantage to a 5000K lamp, as long as it's a high output design triphosphor. Paul Mozarowski.

I have been observing my own rooted cuttings under Phillips alto 830, and GE K&B. Of the cuttings I stuck, with leaves already grown, then the K&B color spectrum is perfect. Rich in red, root production is very favourable. However, when it comes time for new foliage to grow, I find that in that light, the rose foliage comes out kind of yellow-green, not very green at all, definitely not a healthy color. I had one cutting under K&B, and although it had several really big canes with lots of leaves, the color was pale. I then put the same cutting under mix of 1:1 830 and 850 ( mix of 3000K and 5000K), and I am observing the leaves are starting to synthesize chlorophyll, turning dark green starting at the veins and working outwards. My conclusion: 3000K is too warm for vegetative growth, use 4100K or higher for sufficient blue component for production of chlorophylls.
This is based on the results I observe in my own garden. Paul Mozarowski.