Lighting an orchid closet - fluorescent or LED? Otherwise?

[fishmommy]

littlefrog: could you tell me what to look out for in a 'junk' LED unit?
I am trying to learn as much as I can before converting my aquariums and terrariums. May even be a potential to replace my HPS someday...

[littlefrog]

Originally Posted by fishmommy

littlefrog: could you tell me what to look out for in a 'junk' LED unit?
I am trying to learn as much as I can before converting my aquariums and terrariums. May even be a potential to replace my HPS someday...

I think it is always caveat emptor... If it sounds too good to be true, it probably is. I see a lot of wildly exaggerated claims out there. If it claims to last forever and cut your utility bill by 90%, it is probably not going to do that.

Some of it is truly apples and oranges. How do you compare a red/blue LED system to a white fluorescent? It isn't possible I think. Short of actually using both of them. You will never see enough documentation on actual wavelengths or lumen outputs. Even if you could understand it (i've tried, and it doesn't always make sense even to me), they don't provide it. One reason is that LED manufacturers guard their secrets (any reasonably competent person with a soldering iron and good fine motor control can build LEDs and copy a design). We can do a better job of comparing white to white (the last several posts have been trying to do that), but even that is tricky as you have probably deduced.

There are so many systems out there I can't keep up... In general, I think if it is really cheap for purchase, you can probably assume it is cheaply made. Might be some good cheap stuff out there, but I'd be really careful. There is a counter tendency out there, some manufacturers make their units insanely expensive, presumably so you think they are insanely good. They might be better, almost certainly better than the cheapo units, but are they really worth 2, 3, or 5x the price of a middle of the range product? I can't afford to find out.

I'm pretty comfortable with the systems I use, comfortable enough to become a reseller of them. Last thing I need is for people to start blaming me for bad product. But even those systems have ups and downs. I've been having some serious trouble with one of my workhorse units (I use well over 20 of them), I've had to send a lot of them back for repairs. But, to the company's credit, they fix them for free and have even taken my suggestions for an upgrade to the product. I'm getting some new upgraded units this week (for free!) to test out, I have high hopes. I've spent a lot of time with another LED designer, and he's taken a lot of suggestions about how to make better plant lights and put them into practice, so that is another product I'm confident in. But that is just two vendors. There are dozens if not more people making these things out there, I just can't test them all.

Anyway, for what I've tested, I'm comfortable and can give recommendations. For example, I'm _extremely_ happy with the 90W UFO light I use. I can't tell you how many orchids I've bloomed under them (I have five running), and it is solid. I know how to use it (distances from plants, coverage area, etc). But another product, even a 90W UFO, from another vendor... Well, who knows.

[DavidCampen]

1 single 4' t-5 strip fluorescent (without reflector) : $30. Add in a reflector for $20 (or build your own, which is what I do, for less). Anyway, about $50.

1 single 4' HO LED light - $100. Need a transformer, unfortunately. Let's say another $50 (can run several strips though). Total, about $150

For the first couple years, the T-5 wins. Need to buy a new bulb every year (yes you do... stretch it to 18 months if you must, but you will be a far happier person if you replace them yearly). Hydrofarm's price for a 4' 54W bulb is $30. Seriously? $30? That is insane. Anyway.

Really, you pay $30 for a 4 ft. 54W T5 bulb? Yes, that is insane. I buy them for about $10 - $15. That makes break even about 6 - 10 years.

[littlefrog]

Originally Posted by DavidCampen

Really, you pay $30 for a 4 ft. 54W T5 bulb? Yes, that is insane. I buy them for about $10 - $15. That makes break even about 6 - 10 years.

I don't pay that, I was just looking for a price on the internet... But, somebody is paying that! Probably people who are growing far more profitable crops than orchids.

[DavidCampen]

Originally Posted by littlefrog

I don't pay that, I was just looking for a price on the internet...

But you were willing to use that insane number to skew your economic argument.

I just looked for a price on the internet and see numbers of $7 - $12 for 54W t5:
T5 HO Lamps - Fluorescent T5 HO Lamps - Lamps - Discount Specialty Farm, Greenhouse & Garden Supply Store: Horticulture Source

[littlefrog]

I wasn't trying to skew anything, I took the first number off the list of google results, and was working from numbers I actually saw when doing research on the best systems for my own use last fall. I find your attitude annoying. I'm trying to give useful information about pros and cons of both systems. I use both fluorescents and LEDs, and find advantages in both. I'm glad you have the time to correct my numbers, enjoy your superiority.

[BioWheel]

Topstar T5 HO Fluorescent Lamps - Plantlighting Hydroponics & Grow Lights

4 CFL T5's for about $16

[naoki]

Thank you Rob for lots of insights about LEDs for plants!

So with your LED UFO light, how far do you put it from plants and what the coverage area (let's say the area where you can grow low-moderate light requirement orchids such as paphs)?

Also, I'm sure lots of people would be interested in your LED strip. What kind of coverage (reasonable for orchid growth) do you get? Maybe photos? I've heard Finnex Ray II is pretty decent (at the PAR level).

I think one of the advantage of LED is that there is a possibility that they can make the emission spectrum which imitate the photosynthesis action spectrum. So I'm more interested in the development of blue/red systems than white LEDs. After reading a little bit more about white LEDs, they use phosphor to create more white light. So the blue-end of action spectrum is generally well covered, but red end is a bit low (with cooler white LEDs). After looking at some of the available emission spectra, I don't think David's blank statement about all white LEDs or florescent lights are similar is correct. At the PAR level, they may be similar, but it is not quite same as effectiveness to photosynthesis (or at PUR level). Comparison between (or within) red/blue systems, and white LED systems (or any other systems) can be done with measuring the spetra and use the general photosynthesis action spectrum. Or the comparison at the plant level is even better with CO2 gas exchange system (like Li-Cor 6400) to measure photosynthesis rate, or set up experiments to measure the actual plant growth (which takes time).

[littlefrog]

Originally Posted by naoki

Thank you Rob for lots of insights about LEDs for plants!

So with your LED UFO light, how far do you put it from plants and what the coverage area (let's say the area where you can grow low-moderate light requirement orchids such as paphs)?

Also, I'm sure lots of people would be interested in your LED strip. What kind of coverage (reasonable for orchid growth) do you get? Maybe photos? I've heard Finnex Ray II is pretty decent (at the PAR level).

I think one of the advantage of LED is that there is a possibility that they can make the emission spectrum which imitate the photosynthesis action spectrum. So I'm more interested in the development of blue/red systems than white LEDs. After reading a little bit more about white LEDs, they use phosphor to create more white light. So the blue-end of action spectrum is generally well covered, but red end is a bit low (with cooler white LEDs). After looking at some of the available emission spectra, I don't think David's blank statement about all white LEDs or florescent lights are similar is correct. At the PAR level, they may be similar, but it is not quite same as effectiveness to photosynthesis (or at PUR level). Comparison between (or within) red/blue systems, and white LED systems (or any other systems) can be done with measuring the spetra and use the general photosynthesis action spectrum. Or the comparison at the plant level is even better with CO2 gas exchange system (like Li-Cor 6400) to measure photosynthesis rate, or set up experiments to measure the actual plant growth (which takes time).

It is too early to tell on the LED strips what the optimal setup might be. I'm just now starting to use them. I hate to get too excited before I know they work.

There are some pictures (and boring videos) of my setup posted on my website, which might be more instructive... But for the UFOs, I have two configurations. One is lighting an area about 4' long by 5' wide, at about 2.5' above the plants. Under that light I grow my larger bromeliads and a lot of my potted tolumnias. A lot of phragmipedium as well. I was worried about the tolumnias, but they did well under that condition. Under another light with the same setup, I grow cattleyas and vandaceous (Ascocentrums, I don't really do vandas). Had really good blooming on all of that last year, and won the cattleya trophy again with my Tutenkhamun 'Pop', so something might be working.

That is high light, so 4x5' or maybe 5x5' for those types of plants. Of course I try to arrange the highest light plants in the middle, but cattleyas still bloom at the edges. The other configuration I use for the 90W UFOs is over my hanging plants. I have the lights mounted close to the ceiling, and the baskets hang from rods at about 6' high, so the lights are about 3' above the plants. Under all the baskets I have a bench which I put ferns and paph seedlings on. Three of the UFOs cover an area 60" wide by 14 feet long. High light stuff in the middle, foliage on the edges.

I think for paphs, depends on the types. I grow mostly maudiae and bulldog types, for those I would anticipate 6'x6' coverage at 3.5' would be good. If I grew many multiflorals, I'd put them in the middle of that arrangement, and the Maudiae types on the edges. However, I don't actually use UFOs for Paphs... I actually grow all my paphs under a different light unit, the 'Glowpanel 45' - it is a square unit. Three glowpanels per 8' bench (my benches are 30" wide), as high up as I can get them (2 feet?). That was completely awesome, I have not had that much fun growing paphs in many many years.

Third LED light i have is a 300W panel. That is overkill under any orchid circumstances, I think. Too expensive to recommend, so I'll skip it for now.

There is a lot of real science to do... Some of it is being done, but there is a lot of opportunity. I am not a plant physiologist, but I strongly suspect the optimal spectrum for orchids will be variable, but not based on taxonomic relationship. At different levels in the forest canopy one would expect to see different available photosynthetic radiation. Leaves and forest cover above the orchids will determine which wavelengths get through. Evolution being evolution, I would predict that the orchids under deep cover (forest floor) would be optimally collecting at different spectra than orchids under very little cover. I don't know enough to predict what that means in terms of spectra, but it is something I hope somebody looks at. I could be totally wrong, too, that is the beauty of a hypothesis.

[naoki]

Originally Posted by Ray

Naoki (and anyone else interested), take a look at sevengens.com. It is a website for LED horticulture.

I have been communicating with Don, the owner, and they are finding that plants respond differently to individual wavelengths in some cases, which may lead to a greater productivity.

So far, the majority of their work is with berries and vegetables, but they are developing emitters and controllers that allow one to vary the spectrum to suit your needs.

Interesting stuff.

Thank you, Ray. Yes, I have been following a little bit of his stuff. To be honest, electronics part is a little too technical for me, but I'm learning. You are right about the response to the light spectrum. For example, FR:R ratio plays roles in photoperiodism (initiation of flowers), and also etiolation. Some orchids don't seem to care about photoperiodism (maybe because they are in tropics, and always understory??). But it would be interesting to have LED with controllable spectrum.

Originally Posted by littlefrog

It is too early to tell on the LED strips what the optimal setup might be. I'm just now starting to use them. I hate to get too excited before I know they work.

I think for paphs, depends on the types. I grow mostly maudiae and bulldog types, for those I would anticipate 6'x6' coverage at 3.5' would be good. If I grew many multiflorals, I'd put them in the middle of that arrangement, and the Maudiae types on the edges. However, I don't actually use UFOs for Paphs... I actually grow all my paphs under a different light unit, the 'Glowpanel 45' - it is a square unit. Three glowpanels per 8' bench (my benches are 30" wide), as high up as I can get them (2 feet?). That was completely awesome, I have not had that much fun growing paphs in many many years.

Thank you very much for detailed info, Rob! Hmmm, I was probably using 90W UFO LED incorrectly (too close to the plants). I placed it about 2.5' from the canopy of multifloral paphs, and I was getting sharp borders between the central bright area (about 1' x 1'), which a normal lightmeter (Gossen Ultra Pro) reads around 900fc (and higher in the very center). Outside of it it sharply drops to 300fc or so. Obviously with red/blue type grow light (mine is 5-band), the fc value isn't quite comparable to other white light source. I think cool-white fluorescent light has about 22-27% usable spectrum. So if red/blue LED has close to 100% usable spectrum (I don't know if this is true or marketing gimmick). So does 250fc of red/blue grow light give similar photosynthetic activity as 1000fc of fluorescent? So probably I should have place it further to get dimmer light, but wider coverage. It is possible I got a wrong kind of UFO LED, which has more spot-like light pattern. Mine is from Hydroponics hut, which was recommended in marijuana forums. I guess they requires higher light, so they may prefer more focused design.

Growpanel 45 sounds interesting. I should check it out.

Originally Posted by littlefrog

There is a lot of real science to do... Some of it is being done, but there is a lot of opportunity. I am not a plant physiologist, but I strongly suspect the optimal spectrum for orchids will be variable, but not based on taxonomic relationship. At different levels in the forest canopy one would expect to see different available photosynthetic radiation. Leaves and forest cover above the orchids will determine which wavelengths get through. Evolution being evolution, I would predict that the orchids under deep cover (forest floor) would be optimally collecting at different spectra than orchids under very little cover. I don't know enough to predict what that means in terms of spectra, but it is something I hope somebody looks at. I could be totally wrong, too, that is the beauty of a hypothesis.

I'm not trained in plant physiology, neither, although I have published ecophysiology-type papers. I know some understory plants like Begonia has red-coloration underside of the leaves, and this is supposed to be one of the adaptation to what you are talking about (I forgot about the details, but the BBC video, The Private life of plants, talked about it). I thought that the chloroplast is relatively conserved among different taxa, but I should ask about this. But anyway, it's an interesting stuff.