LED Light vs Flourescent Lights

[Destan77]

Hi,

Any has any experince with LED lights as compared to traditional flourescent lights for orchids?

LED lights are generally brighter but it this type of light suitable for orchid growth?

Any advise would be a great help.

[kaarthiik]

I think, yes LED is better to floroscent, as they emit less heat. I am using CFLs in addition to indirect sunlight (have less light). And my dends Vandas and Phals are doing better than in indirect light alone.

[Connie Star]

I'm not an expert on this topic but there are a couple of discussions about it here on OB.
Cost is a factor- the ones that put out a lot of light are very expensive.
Then, there is the issue of wavelengths. Apparently they vary and not all are useful for plant growth.
Check out this thread:
http://www.orchidboard.com/community...ed-lights.html

[greenbean]

Connie is right. The LEDs that emit sufficient light for plant growth are expensive, but on the other hand they are very energy efficient and last for a very long time. The wavelength issue is the real problem. Part of their efficiency is that LEDs emit a very narrow spectrum of light depending on their color. Any one color of LED may not include even part of the spectrum needed for plants, much less the whole range of wavelengths required for photosynthesis and proper development.

Any fixture using LEDs for plant growth would require a mix of different colors of high output LEDs to encompass the full spectrum of light required by plants. These setups can be prohibitively expensive.

[littlefrog]

I'm not doing quite the right experiment to answer your question, but just today I started an experiment. I've never used LED and am strongly considering buying a very large number of them, so needed to get at least a rough handle. I am comparing greenhouse to LED. It isn't the best experimental design, but it is the best I could do with the budget and space I have.

Group one: Mixed ferns, foliage, bromeliads, several masdevallias, three paphs from different groups (purpurescens, a white complex, and Prince Edward of York), a besseae type phrag hybrid, several cattleyas, and a few dendrobiums. Growing in a large tray in a 'representative' part of the greenhouse.

Group two: Exactly the same mix as above, with the plants matched as closely as possible. Most of them are clones, but the paphs and phrags are seed grown, best I could do. In a very similar arrangement in a large tray. ~14" below LED lighting, on a shelf in my basement where there is minimal additional light.

The LED light is a 'Sunlight Supply 45' panel, 28 W total draw, 5:9 ratio of blue to red (i'd have preferred the reverse, but that is what was available when I was shopping). Supposedly this replaces a 250W HID light - I've grown under HID and I'm not buying that... But it is scary bright. By that I mean don't look at it directly, and the light color is extraterrestrial. Plant leaves look black, which means it is working (the leaves are absorbing the available light and not reflecting any obvious colors).

I made a little video with my fancy new camera of the whole thing. I'll make another video in approximately a month where I compare the plants. Might even post them.

Now to your question. I know that I can grow as well or better under fluorescent lighting (T8, haven't tried T5's yet) as I do in the greenhouse. I hope to demonstrate to myself whether I should build a new greenhouse (at substantial cost and township hassle), or convert a large pole barn to a large grow room with LEDs (or some other light). Also at substantial cost, of course. My calculations seem to say that LEDs, if they really do last as long as they are supposed to and use as little energy as they are reputed to, should pay for themselves within a year when compared to HID lights, and maybe 2 years compared to T8s (T5's aren't really much cheaper than LEDs). Compared to a greenhouse, it cost me more than $4000 to heat my greenhouse this winter. Lights and a well insulated barn have got to save me money. If it works! If it doesn't work, then I'll just suck it up and pay the damn heating bill.

Anyway... Enough rambling. If LEDs give me a similar growth profile to the greenhouse, I'll use them. If not, I have to decide between fluorescent (and/or HID) and the greenhouse. Really hard to justify the greenhouse, quite frankly. Heating costs have doubled in 7 years, I can't imagine they will go down. I'll give you an update in a month.

[greenbean]

Neat experiment! I hope you do post your results, I'll be interested to see how the different plants did.

The black leaves are probably what I like least about LEDs. Manufacturers could include some green LEDs in the fixtures to improve the color, but then you would be paying for light that the plants don't use. I guess the way around that is to just deal with the weird lighting in the grow area and have the plants in a display area when they bloom.

[silken]

Very interesting and I will be interested in the final result.

[johnblagg]

well that is a interesting experiment ...but comparing a G/h to leds is like comparing a High intensity lighting to leds not realy a fair comparison ...now if it was compact flouresents and leds or t5s and leds it would be much mor realistic.

A greenhouse is just about as good as you can do and leds at the moment are the least powerfull of all lighting you can get so you compairing the very best to the oppisit end of the range.

The actual answer we need in relation to leds is has anyone grown orchids under leds alone yet all the way to bloom?

[Ray]

Originally Posted by littlefrog

... the light color is extraterrestrial. Plant leaves look black, which means it is working (the leaves are absorbing the available light and not reflecting any obvious colors)....

That's my objection to such panels. If your interest is merely growing plants, and not looking at them or their flowers, they're great, but for most orchid folks who actually want to appreciate their plants, it's awful.

Don't forget: the red/blue LED panels were developed for marijuana growers who couldn't care less about how the plants appear, but wanted to avoid the high power bills that often lead police to your basement.

[littlefrog]

Well, I must say that I enjoy looking at plants too, but to pay my bills I really need to get them to grow. A lot of what I sell is foliage, so it really only matters what they look like when they go out the door. Boy do those plants look weird under LEDs though. The final outcome will probably be some combination of LEDs for growth (assuming they work), and some other sort of lighting for actually working in the space. The point about marijuana growers is well taken. In fact, if the DEA is tracking my web movements I'm doomed, since I've spend hours on the pot growing sites trying to figure this out. I am assuming that if anybody knows how to do this, it is the people who are making real money at it.

When I have more indoor space (the pole barn) I will certainly compare HID to LED lights. I have several Metal Halide lights already, and I grew under MH and fluorescent exclusively for ... oh, at least 10 years. So I know what to expect from them... But that isn't actual science. I'll do a direct comparison between LEDs and fluorescent when I have the right space, and also the comparison between LEDs and metal halide. I'll certainly let you know when I have better answers.