Lighting Questions

I was going to resurrect one of the old lighting threads but decided it might be easier to just start a new one! I'm probably going to supplement with a simple fluorescent setup myself, but I've got some questions from the reading I've been doing...

Why don't people use halogen lights? I know they heat up, but since they're bright they shouldn't need to be so close to the plants. They're supposed to emit well particularly in the blue spectrum and we know that is good for improving stomatal conductance in Paphs.

Are people moving to LEDs or is that technology not quite there yet? The marine tank guys certainly seem to be using it and corals must be almost as fussy as orchids. I know for reef tanks heat is a real issue, so LEDs win on that front, but are they any good for orchids, Paphs in particular?

Since extra blue light is good, do people use actinic tubes to supplement their normal light? I haven't seen it mentioned anywhere, but wouldn't it make sense?

And what about the SHO CFLs? Has anyone tried them yet?

Sorry if these are silly questions

I've tried quite a few lighting systems in the last 30 years or so.
I began with T12 fluorescents, they worked well in the 4 foot and better in the 8 foot sizes. There was one model with twisted tubes. I've got a few still working in my kitchen.
The best fluorescent tubes now are T8 and T5. The smaller number you go, the thinner the tube and the more efficient light production. I've also tried with good results CFL tube in the 250 Watts output with Mogul screwing end. They are very bright and take little place. They are very brittle though, so don't use too much torque when screwing them.
Of course, I had sodium and metal halides in both 400W and 1000W ranges. If you can deal with the heat and the cost of electricity, the latter are great.
LED panels work well too. The blue and red bulbs are good, require little electricity and give very little heat. These are best for cool growing plants, but the colour they emit give us the impression that the lighting is insufficient. However, we have to remember that plants use only red and blue light. For best results, the top of the plants must be at most 4 inches from the lights. Put them closer and they may grow funny. I use them with T8 lamps for my masdevallias so the result can be more pleasant to my eyes. The early spot types LEDs were junk and of very lousy workmanship. New models are appearing all the time but they are quite expansive.
T5 lamps give more light than comparable T8 but cost more.
There is a great variety of fluorescent tubes out there and a possible combination of tubes. The blue tubes used for fish tanks give a lot of blue light but you couldn't grow orchids on those alone. Sellers recommend using the blue tubes for growth then replacing them with red tubes to induce flowering.
Finally, several years ago, one type of spotlight called Wonderlite came out and are still available in some garden catalogs. They last for a long time but produce a lot of heat. Avoid halogen lamps. The may be pleasing to our eyes but as far as plants are concerned, it's wasted money.

The reef guys are also using T2 lamps, have you tried those out?

In theory using actinic lamps as supplements should have a significant positive effect. Here is a research paper that talks about the impact of blue light supplementation: Stomatal Limitation to Carbon Gain in Paphiopedilum sp. (Orchidaceae) and Its Reversal by Blue Light. There isn't any mention of red light though, is there a link to some info about red lights please?

I wouldn't bother with those as far as plants are concerned. These are high end design lights for certain applications where you want to hide the fixture. Go for the T8. They're cheap, easy to find and give excellent results.

Thanks Shiva Seeing as I'm just working with seedlings at the moment, T8 should be good without breaking the bank!

Basic four foot T8 fixtures with two lamps cost about $20 at big renovation stores. Lamps are about $5 each. And you can add up fixtures one beside the other to give you a total of 4, 6 or eight lamps with a lot of lumens output. For seedlings, you should go with the 6500K temperature with lots of blue-white light.

I'm partial to my t5 light banks. 6 bulbs (mix of warm and cool white 48" bulbs) over a 4'x2' growing tray. Gives me great results for my paphs (probably a bit more light than I need actually).

Shiva has given a lot of good advice.

A 6500°K bulb puts out a spectrum that closely matches both the light from the sun coupled with reflection from the sky, as well as the absorption spectrum of chlorophyll. Not only that, but from an energy flux perspective, the amount of radiation in the blue- and red areas are about 1500x and 50x greater, respectively, than a tungsten halogen bulb.

Like Darin, I am partial to T5's, as well. I recently built a terrarium for jewel orchids (plus a bulbo species I got from Andy's), and 3 x 24W, 2' bulbs were so bright, I had to build a hood elevating them some 18" above the plants.

As to LEDs, I've been playing with some, following the examples of others here, and have found that the newer "phosphor-type" LEDs are looking pretty good. Using a UV or blue LED to excite a phosphor, they emit very bright white light, and as a phosphor can be tailored to provide whatever spectrum you want, many of them are available in the 6500°K area, as well.

Looked at halogens at one point and they are inferior to HIDs in their efficiency. Also, they are usually available in spotlight fixtures with a fairly focused beam which aren't conducive to growing orchids.

The fancy tubes reef keepers use are usually selected for their cool burning nature. The work great, but range of coverage (square footage) is limited. The lighting set up is expensive, but it's a one time investment for them. Remember, most reefkeepers just have one or a few tanks and they can't expand beyond that unless they buy more tanks ($$$$). Orchids are less space limiting and it's easier to expand a collection. I agree with Shiva in that fluors are great.

T8s are more efficient than T12's but you might actually get less light from a T8 overall. You just have to shop around, not all tubes of the same specs (wattage, CRI, and temperature) are created equally. Watch out because more efficient bulbs might advertise the output per energy usage (lumens per watt) instead of the actual output of the tube. Not a huge issue for seedlings, but mature plants will want all the light a fluor fixture can give them. T5s are superior to T8s and T12s but initial investment is much higher. Not an issue with a small collection but expect yours to grow (as in both plant size and quantity of plants).

As far as temp selection, 6500 are considered "full spectrum" or "daylight" bulbs. They have lots of all colors, so the portion that is green is lost as far as your plants are concerned. The higher the K temp, the closer to white essentially. Blue light is typically around 4,000-5,000 K (cool white). Red/orange light is ~3,000 K. If you really want to get into it, look at the output spectrum of the bulbs available to you. You want little green and maximum blue and red. Consider the combined spectrum of all the tubes you'll be using- many folks mix tubes in a bank of 2-4 to cover all the bases. I think Shiva posted using 6500 K and 3000 K or something like that. We used to use simple warm and cool white tubes mixed ~1:1.

If you go fluors, replace them regularly and rotate replacement. They lose their output intensity (drastically after about a year for T8s and T12s).

i use metal halides for my adult paphs and swear by them. The plants love the blue light, and MH bulbs are also easy on human eyes. i change the bulbs every 9 months. I also use 4' fluorescents for seedlings...

Thank you. Very timely thread.

For anyone who want so see same facts here is a very interesting website, but it´s in german. Perhaps Google Translate will do a good job (?): http://www.hereinspaziert.de/Sehlicht_2009/Ergebnisse.htm

At the end, the results confirm Shiva´s explanation.

I'm trying xenon lighting myself in a small area.

I used T5 lamps for quite a while, the 45.8" length 54 Watt tubes. I used those aquarium specialty bulbs and I actually had fantastic results. I used ATI Aqua Blue Special in the 14K - 15K spectral range in combination with their Purple Plus and ProColor (red) tubes. I also added in some Giesemann Aqua Flora, Midday Sun, Aqua Pink and AquaBlue Plus tubes. I had tons of useable blue and red rays and my plants grew amazingly well under the spectrum I had created. The intensity of the light was a bit much as was the heat produced, and I found that I needed to move the lights further away from my plants than orginally anticipated. The other downside was the cost of the tubes since they need to be replaced annually. Aquarium tubes are much more expensive than other types.

Now I grow under Ceramic Metal Halide lamps. They are 400 watts each and truly full and wide spectrum in their output. Yes, the green portions are wasted on the plants, but the overall light they give off is more pleasing than very blue, yellow or red light sources and more easy on the eyes as well. My plants not only grow very well under these lights but they look great too without having to be removed to another part of the house in order to enjoy them. The heat is easily dealt with by using fans. I simply blow it away. These CMH bulbs are made by Philips and they only run on magnetic ballasts designed for use with HPS lamps. If you use a MH ballast or a digital ballast you will ruin the bulbs almost immediately. The bulbs are rated for safe use in open fixtures, but you can use them in an enclosed fixture if you prefer. This can be especially handy if you want to use an in-line cooling and exhaust system using can fans which hook right into the ducting.

Now I am starting to get more and more interested in LED lighting. Aeon Lighting makes a BR30 15 watt lamp which is 4300K in color and gives off a whopping 1475 lumens. This is also a full spectrum lamp which will be pleasing to the eye but does include parts of the spectrum which the human eye uses and plants do not. Still, orchids grow very well under these lamps. You would need several bulbs, of course, and they are expensive, but I believe this is the wave of the future. If you order your LED lamps with a narrow beam angle you can even mount them 2' or more above your plants and still get strong light along with good coverage. Orchids Limited is selling these now.

A Korean company just recently announced they had developed a new LED which runs on A/C current (no conversion to D/C current needed) and it produces 100+ lumens per watt as well. Exciting news!

LEP is another light source which is up and coming. A small tube about the size of a small bean is bombarded with radio waves and produces an intense full spectrum light. These are now being made into street lights, aquarium lights and even grow lights, but to be honest, the cost is still prohibitive.

Within a year or two I believe we will see amazing things in LED and LEP lighting which will revolutionize orchid growing.

Thank you everyone for the great discussion and ideas! Yes I also think LEDs and LEPs will have even more impact over the next few years.

Just out of interest and because I like reading research papers I found one that talks about red light: Phytochrome and Blue Light-Mediated Stomatal Opening in the Orchid, Paphiopedilum. This one basically says that red light enhances the blue light response, opening up the stomata more, confirming what everyone has been saying about providing both red and blue Have you guys all read these papers before?! I couldn't see them mentioned anywhere in previous threads...

Wide open stomata means more gas exchange and if other culture conditions are right, potentially faster growth. I think it's fascinating that Paphs have evolved to not have chloroplasts in their guard cells and to rely on blue light for controlling stomata. Whereas Phrags are more normal and have guard cell chloroplasts. Funnily enough many corals also rely on blue light or rather the Zooxanthella algae they form a symbiotic relationship with rely on it.

I first started reading about blue light as I was interested in knowing more about CO2 supplementation. The research seems to be saying that without blue light supplementation and possibly red light enhancement, CO2 supplementation would not achieve much as the Paph stomata would simply not open wider to allow the plants to use the additional CO2. It's like Paphs have evolved to grow slowly. I wonder what natural selection parameters caused that to happen?

i have a 8 x 14 growing area with HPS 1000 watt (Red) on one end lighting the BS plants and a Halide (blue) on the other end covering the seedlings....i get overlap and the plants seem to love it

hchan said:

I wonder what natural selection parameters caused that to happen?

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Is there a limited range of latitudes in which Paphs are found in nature? Perhaps the angle of the sun's entry into the atmosphere had at least some small influence in this natural selection. I could be totally wrong, too, but it was just an idea that popped into my vapid brain tonight.

I'm a reef keeper. LED's are just starting out...while more people are trying them, they are not the standard yet...it will be a few years before that For one thing, they cost too much now. Right now, the big thing after halides is T5 fluorescents. I'm still using my PC fluorescents...55 w 10,000k and actinic. No sense in buying new ones when they still work.

Ricky said:

For anyone who want so see same facts here is a very interesting website, but it´s in german. Perhaps Google Translate will do a good job (?): http://www.hereinspaziert.de/Sehlicht_2009/Ergebnisse.htm

At the end, the results confirm Shiva´s explanation.

Click to expand...

Thanks for this, I translated it and it's a good summary, though the translation was a bit hard to understand in places!

NYEric said:

I'm trying xenon lighting myself in a small area.

Click to expand...

Let us know how it goes!

Eric Muehlbauer said:

I'm a reef keeper. LED's are just starting out...while more people are trying them, they are not the standard yet...it will be a few years before that For one thing, they cost too much now. Right now, the big thing after halides is T5 fluorescents. I'm still using my PC fluorescents...55 w 10,000k and actinic. No sense in buying new ones when they still work.

Click to expand...

When you retire your actinics one day, keep them for your Paphs! Yes LEDs are expensive, even though they're supposed to be cost-effective etc, but the upfront costs for the high-end ones are pretty steep.

Lanmark said:

Is there a limited range of latitudes in which Paphs are found in nature? Perhaps the angle of the sun's entry into the atmosphere had at least some small influence in this natural selection. I could be totally wrong, too, but it was just an idea that popped into my vapid brain tonight.

Click to expand...

Shorter wavelengths such as blue are scattered as described by the phenomenon of Rayleigh scattering. So yes it makes sense that areas close to the equator get more blue light, as there is less atmosphere for it to travel through. In the research literature, actual measurements of short wavelength variance as a function of changes in latitude tend to focus on UV light for obvious reasons, but I guess the same would apply to blue light to a certain extent. However it still seems curious though as even in situ growth is slow, would people agree? You'd think that they would evolve to grow more quickly so that they would pass their genes on. Unless they were in an area that was so safe that there was no need to select for speedy growth, as disease/death before reproduction simply wasn't an issue. Maybe also theirs was such a stable environment that quicker growth for quicker adaption to changing conditions also wasn't necessary? I bet they regret that now!! Poor Paphs...

ehanes7612 said:

i have a 8 x 14 growing area with HPS 1000 watt (Red) on one end lighting the BS plants and a Halide (blue) on the other end covering the seedlings....i get overlap and the plants seem to love it

Click to expand...

Are the ones in the overlap area the happiest?

hchan said:

Thanks for this, I translated it and it's a good summary, though the translation was a bit hard to understand in places!



Let us know how it goes!



When you retire your actinics one day, keep them for your Paphs! Yes LEDs are expensive, even though they're supposed to be cost-effective etc, but the upfront costs for the high-end ones are pretty steep.



Shorter wavelengths such as blue are scattered as described by the phenomenon of Rayleigh scattering. So yes it makes sense that areas close to the equator get more blue light, as there is less atmosphere for it to travel through. In the research literature, actual measurements of short wavelength variance as a function of changes in latitude tend to focus on UV light for obvious reasons, but I guess the same would apply to blue light to a certain extent. However it still seems curious though as even in situ growth is slow, would people agree? You'd think that they would evolve to grow more quickly so that they would pass their genes on. Unless they were in an area that was so safe that there was no need to select for speedy growth, as disease/death before reproduction simply wasn't an issue. Maybe also theirs was such a stable environment that quicker growth for quicker adaption to changing conditions also wasn't necessary? I bet they regret that now!! Poor Paphs...



Are the ones in the overlap area the happiest?

Click to expand...

all the plants seem to be happy:clap:...i think either using halide or sodium is beneficial (i am testing this theory ) enough for any stage of growth . I believe they can acquire enough photons for their desired wavelength from either lamp because paphs are so slow.