High Output Florescent lights

[Stray59]

Hey everyone !
I went to Home Depot yesterday and found a two-tube, T5, High Output florescent light strip - $39.97 in Indianapolis. The two HO bulbs cost an additional $20.00 and I have yet to purchase the power cord (they will get you on anything), which is hopefully under $20.00. It is rated at 8900 lumens and has a efficient, low heat, digital ballast. It claims to put out 2X's the light of a comparable standard T5.
Phillips puts out the bulbs I have (F54T5/TL841/HO/ALTO), and they state that they put out 5000 lumens (?). The box gives the following ratings: color Rendering Index of 85; color temperature of 4100 k, wattage of 54.
I know nothing about these, or florescent lights in general, and the man at the store stated they were new to the market. The fixture is put out by Lithonia brand, but Sylvania is advertising the same thing and obviously Phillips is at least supplying bulbs. I was told they will ONLY use HO bulbs, but I am a little stumped about the difference lumens of the fixture and the bulb; did I just buy a dimmer bulb? It was the only bulb they had for these fixtures.
Has anyone had any experience with or know anything about the usefulness of of these related to orchid / plant growing? What does the color rating and color temperature indicate to you?
Any feedback is really appreciated.
Thanks
Steve

[Call_Me_Bob]

HO lights have been used for a good bit for planted aquariums and also for orchids, they just havent hit stores like home depot until recently. a HO light gives off significantly more light than a NO (normal output) light so they are definitely worth it! you might be able to get them cheaper online though (although you might not)

as far as color temperature, 6500k is the closest thing to sunlight so its what i use and what ive seen people recommend. although 10000k if i understand correctly is also useable, but things like soft white (2500k) arent as good.

[zxyqu]

T5's are great for indoor growers, and definitely go with HO fixtures and lamps. I'd avoid the 10000k bulb, and stick to a 6400K, with maybe a 3000K bulb thrown in for some more red spectrum. 6400K alone though will work great. I'll also say I think you can get a much better price on these fixtures, and bulbs online. Hydrofarm and Quantum's are the best in my experience. Good luck

[Connie Star]

Hi Bob,
I think 10,000k is in the ultraviolet range- not where I can look it up, though.

[Call_Me_Bob]

Originally Posted by Connie Star

Hi Bob,
I think 10,000k is in the ultraviolet range- not where I can look it up, though.

really? thats odd. we use it for planted aquariums all the time, usually along side a 6700k but sometimes alone.

[DavidCampen]

Originally Posted by Call_Me_Bob

really? thats odd. we use it for planted aquariums all the time, usually along side a 6700k but sometimes alone.

Color temperature has very little meaning when applied to fluorescent lights. When a manufacturer calls a lamp 10000K, all that means is that the manufacturer is trying to imply that this lamp will look bluer than another lamp that is said to be 6000K. As Connie said, a true blackbody radiator at 10,000K would be emitting mostly in the ultraviolet.

As for lumens - this is a measure of how bright a light would appear to a _person_. Human vision is most accute with green light at 550 nm and drops off very rapidly at the wavelengths that plants best utilize. If you want the most lumens per watt then get a lamp that emitts green light, it won't be very good for plants though. This is why fluorescent lamps that have the highest lumens per watt have lower Color Rendering Index (CRI) values; to increase the lumens per watt the manufacturer has to increase the proportion of green light which lowers the CRI.

In terms of supplying the most amount of fluorescent light per watt that will be useful for your plants, the color of the fluorescent bulbs is not very important. The best you can do is try to get a lamp that produces very little green light, to do that though you would have to look at the emission spectrum of the lamp not the so called Color Temperature and not many manufacturers provide emission spectra charts for their lamps.

[Call_Me_Bob]

Originally Posted by DavidCampen

Color temperature has very little meaning when applied to fluorescent lights. When a manufacturer calls a lamp 10000K, all that means is that the manufacturer is trying to imply that this lamp will look bluer than another lamp that is said to be 6000K. As Connie said, a true blackbody radiator at 10,000K would be emitting mostly in the ultraviolet.

As for lumens - this is a measure of how bright a light would appear to a _person_. Human vision is most accute with green light at 550 nm and drops off very rapidly at the wavelengths that plants best utilize. If you want the most lumens per watt then get a lamp that emitts green light, it won't be very good for plants though. This is why fluorescent lamps that have the highest lumens per watt have lower Color Rendering Index (CRI) values; to increase the lumens per watt the manufacturer has to increase the proportion of green light which lowers the CRI.

In terms of supplying the most amount of fluorescent light per watt that will be useful for your plants, the color of the fluorescent bulbs is not very important. The best you can do is try to get a lamp that produces very little green light, to do that though you would have to look at the emission spectrum of the lamp not the so called Color Temperature and not many manufacturers provide emission spectra charts for their lamps.

thanks for shedding some light on that!

[Stray59]

I understand what you are saying and it makes sense. I appreciate everyone's input, but to be honest I feel the conversation has taken some confusing tangents. I am not a "light" person in the sense that I have never studied lightwaves, emission sources, human vs. plant light perception; at least not to the incredible lengths that some of you have.
I kind of wish I had just asked for a good brand and model number but I doubt that this would have altered too much of the discourse as I am sure that every choice would have multiple opinions.
Currently I have 1-T12, 2-T8s and one T5 HO fixture. I will be adding more T5 HO, but to be honest the combo of the T12 and the T8 bulbs are working nicely as I have a Brassovola nodosa that is moving into bloom under these lights. I will post the pics when it does open.
I was able to find the light scale on that package that showed where the T12 and T8 bulbs rated and I mixed red and blue tubes. The T5 had no scale, so I will let you know how they work out.
Thanks for everything !

Steve

[Ray]

Originally Posted by DavidCampen

Color temperature has very little meaning when applied to fluorescent lights. When a manufacturer calls a lamp 10000K, all that means is that the manufacturer is trying to imply that this lamp will look bluer than another lamp that is said to be 6000K. As Connie said, a true blackbody radiator at 10,000K would be emitting mostly in the ultraviolet.

Once again, none of this is incorrect, but I think you may be treading a bit out of context here, David.

The "actinic" bulbs, often labeled as 10,000°K, that are intended for growing aquatic plants and especially corals, are not merely made to "look" bluer to the human eye - which is what the "corrected color temperature" is focused upon with most fluorescents. In order for there to be an appreciable amount of UV emitted, the glass used to make the tubes is higher in silica and lower in the glass modifiers than are most other bulbs. To take it beyond actinic to UV bulbs used for germicidal applications, the bulbs are pure SiO2, as it does not block the UV.

[Call_Me_Bob]

Originally Posted by Ray

Once again, none of this is incorrect, but I think you may be treading a bit out of context here, David.

The "actinic" bulbs, often labeled as 10,000°K, that are intended for growing aquatic plants and especially corals, are not merely made to "look" bluer to the human eye - which is what the "corrected color temperature" is focused upon with most fluorescents. In order for there to be an appreciable amount of UV emitted, the glass used to make the tubes is higher in silica and lower in the glass modifiers than are most other bulbs. To take it beyond actinic to UV bulbs used for germicidal applications, the bulbs are pure SiO2, as it does not block the UV.

10,000k bulbs are different than actinic bulbs. i dont know what exactly actinic are as far as kelvin, but they are to make colors in a reef tank 'POP' and are usually paired with a bulb in the rang of 6,500 to 10,000 kelvin.