LED question

[Hera]

I've been looking at some different kinds of lighting to add to my setup. I could go for another bank of T5's, but I've been wanting to try the LED lights. I'm considering these from Orchids LTD.

http://www.orchidweb.com/detail.aspx?ID=2428

Please chime in with opinions. My shelves are three feet long and adjustable, so the distances and widths seem ok. And I could put several per shelf. I'm just not sure.......

 

[Sirius]

I have an LED grow light that I will give you if you want to try one. I don't think they are worth the money. You could experiment with one before you buy.

 

[Shiva]

I bought two chip leds for my orchid window. They are very bright but the area covered is not that wide. You would probably need three for every shelves.

 

[Lanmark]

I think what Shiva said is correct. Go with the chip techs and not the diodes. Use several lamps per shelf.

Those typical LED "grow lamps" which Sirius is talking about are indeed pretty much useless. High power focused beam white LEDs are what will work best for orchids.

LEDs hold great promise, but for now you might do even better than those cheaper chip techs offered by Orchids LTD by going with the more expensive Natural White MR-16 lamps manufactured by ALT (also offered by Orchids LTD). The beam angle you select will depend on how far below the bulbs you intend to place your plants.

I am using several ALT Natural White BR30 lamps with the 38° beam spread. The actual LED chips in my lamps are located 28-29 inches (71-74 cm) above the tops of my Neo plants. I'm using plug-in track lighting to hold the lamps. These plants and their LED lights are located in front of an eastern window which I partially shade from the hottest summer mid-to-late-morning rays of the sun using mini blinds. My plants are growing and blooming there very well.

Elsewhere in my home I have Phals growing even further below Philips Endura white LED lamps with a 22° beam spread -- also thriving and spiking. The Phals aren't located close to any windows and only receive ambient natural light from distant windows in the room. Their primary source of illumination is the LED lamps I have provided.

One exception to the purpley grow light rule: Kessil Lighting has recently released a new generation of LED grow lights which have a much higher and more focused output than all other LED grow lights of the past. Their H350 deep purple model would likely work quite well as supplemental lighting for orchids in front of an east-facing window. Otherwise stick with white LED lamps. Cree chips seem to be the best white chips on the market today, but others are in the pipeline which will soon give them a run for their money.

LED lamps are just now starting to provide very bright, concentrated beams of light using very small amounts of wattage. Before now they were not truly viable as light sources for growing orchids well. Now the promise is finally coming true.

 

[Hera]

I haven't made any decisions yet, but thanks for the detailed info. I'll keep you updated when I decide to buy.

 

[Hera]

Shiva, I just went back and looked at your window thread. How is everything doing with your lighting? Looks good to me, but I'm curious how the plants have responded to the red/blue lights. We had a speaker at one of the last couple of meetings talk about the red/blue setup and he was all for it. THe biggest drawback seemed to be the spread of the output. Straight down was the best, and rapidly dwindled as you got further from the edge of the box.

 

[Shiva]

Shiva, I just went back and looked at your window thread. How is everything doing with your lighting? Looks good to me, but I'm curious how the plants have responded to the red/blue lights. We had a speaker at one of the last couple of meetings talk about the red/blue setup and he was all for it. THe biggest drawback seemed to be the spread of the output. Straight down was the best, and rapidly dwindled as you got further from the edge of the box.

All plants are growing well but I had to add three 42W daylight CFL bulbs to light up the scene better. Red and blue may be very good for the plants but it's a bit hard to see them well from a distance. The plants have reacted well with the added light and the first one to spike so far is a Aerangis biloba. There's also lots of new growths. The tree trunk is quickly being overwhelmed by mushrooms but the plant roots seem to like the stuff. My guess is I will have to replace it next summer. I have to spray with water twice a day to keep them happy.

 

[Hera]

Two more questions.

What is degrees spread and how do I evaluate the lumens. It seems that many of the bulbs I've been reading about have much lower lumens than T5's, but I also read that it can't be evaluated the same. Can anyone clarify?

 

[Lanmark]

Two more questions.

What is degrees spread and how do I evaluate the lumens. It seems that many of the bulbs I've been reading about have much lower lumens than T5's, but I also read that it can't be evaluated the same. Can anyone clarify?

I have included some links below which might help. The degree of spread or beam angle is perhaps most easily explained as this: imagine the difference between a flood light and a spot light. A spot light has a narrow beam. Its spread or beam angle may be only 8° for example. A flood light gives off a wide wash of light and has a spread or beam angle of maybe 120° or more. The more spread out the light from a given source becomes, the more diluted it becomes. It covers a wider area, but it is not as intense. The more focused the light is when coming from a given source, the more concentrated it is.

I have found for my own orchid growing needs that I need to use several narrow beam lamps. They give off a more intense concentration of light but cover only a small area so several are needed to get the coverage I desire.

http://www.orchidweb.com/mr16br30meas.pdf

http://en.wikipedia.org/wiki/Lux

When LED sellers make the claim that the lumen output from their LED lamps cannot be adequately compared to the lumen output from T5 lamps, they are saying this because their LED lamps are emitting only certain specific wavelengths or colors of the light spectrum such as blues and reds (measured in nm or nanometers) whereas T5 lamps emit a broad spectrum of light even if they tend toward being warm white or cool white.

White LED lamps cover much more of the spectrum than do those which are only blue and red. While still not quite the same, it is significantly more accurate to compare the lumen output from a warm white LED to a warm white T5 lamp and from a cool or natural white LED to a cool white T5 lamp.

LED lamps do not yet measure up to the lumen output of T5 lamps. Their advantage lies in their ability to concentrate and focus the beams intensely. You can illuminate defined areas very brightly using less wattage and with less heat output. T5 lamps emit light all around the tubes and down the entire length of those tubes. Their lumens are spread out over all that surface area. Some of the light bounces from the reflectors back down into the tubes and gets lost there. A lot of light is scattered and useless. The more focused the beams of your LED lamps, the less light you will waste. You can use wide beam LED lamps, but you will need to place them VERY close to your plants to do any good. I like the headroom so I use narrow beam lamps.

I know there is a lot of research out there showing that plants primarily use certain limited wavelengths of light. My own experience, however, has shown me that plants respond better to full spectrum light than to a simple combination of just two or three wavelengths each of reds and blues. They may not need much of all those other wavelengths, but I think they do find some small benefit from them even if science hasn't discovered it just yet.

Even the white LED lamps which I use do not emit any ultraviolet light, and I often wonder if they emit enough light on the red end of the spectrum as well. This is why I now grow my plants in an eastern window and use the LED lamps primarily as a supplemental light source for my orchids. In a previous post I mentioned some Phals which I have growing under LEDs as their primary source of light. I am not yet fully convinced this will work well in the long run. I suspect they would be happier with a tiny bit of UV light on the lower end of the spectrum and a bit more infrared on the upper end of the spectrum. I could be bat-sh*t crazy too.

 

[Hera]

Thanks for the expanded explanation. There's so much info out there that my head was spinning. I placed an order today for five light on a two foot track. Three are slightly warmer and two are slightly cooler. I'll take pictures when I get it all set up. Down the road I want to add the wide spectrum on a separate shelf so that I can compare results. This should be interesting. I like the lower energy usage and heat output and I would like to expand my grow area without killing my electric bill. Thanks again for all the input from everyone.

Does it take a village to grow a good orchid? I think so:rollhappy:

 

[Ray]

I know there is a lot of research out there showing that plants primarily use certain limited wavelengths of light. My own experience, however, has shown me that plants respond better to full spectrum light than to a simple combination of just two or three wavelengths each of reds and blues. They may not need much of all those other wavelengths, but I think they do find some small benefit from them even if science hasn't discovered it just yet.

How about another possibility:

The absorption of chlorophylls a & b span some pretty good ranges - from below 400 nm up to 500, and again from about 640-700.

A has peaks at 420 and 765 (or thereabouts), while B's are at 480 & 650, so if you pick only certain specific wavelength or narrow ranges, you may hit the peak, but are ignoring the rest.

The graph below (from edublogs.com) also shows absorption by carotenoids, but I have no knowledge of the role they play. Anyone here care to enlighten me?

 

[Lanmark]

How about another possibility:

The absorption of chlorophylls a & b span some pretty good ranges - from below 400 nm up to 500, and again from about 640-700.

A has peaks at 420 and 765 (or thereabouts), while B's are at 480 & 650, so if you pick only certain specific wavelength or narrow ranges, you may hit the peak, but are ignoring the rest.

The graph below (from edublogs.com) also shows absorption by carotenoids, but I have no knowledge of the role they play. Anyone here care to enlighten me?

:clap: That's exactly what I'm trying to say. There are ranges of light utilization by plants with peaks at certain wavelengths. LED sellers whose lamps are tailored to emit 430nm, 450nm, 620nm and 660nm (or four other nearby wavelengths) -- ie LED grow lamps with only blue and red LEDs -- are eliminating a big portion of the light spectrum! My orchids perform much better when they get whole light and not just fractionated light.

Here's a link which explains some of what carotenoids do for plants:
http://science.jrank.org/pages/5303/Plant-Pigment-Carotenoids.html In a nutshell this article states that carotenoids contribute to the process of photosynthesis and they can act as protectants against too much light exposure. :wink:

 

[hchan]

Paphs are a little different to other plants though in terms of how they respond to specific wavelengths. For a slightly different angle on this: Phytochrome and Blue Light-Mediated Stomatal Opening in the Orchid, Paphiopedilum. Spectrum specific LEDs could at least make useful supplemental lighting, opening the stomata can increase CO2 uptake and thus growth: it seems to be one of the factors making Paphs such slow growers...

 

[Ray]

Thanks for both links!

 

[goldenrose]

..... I placed an order today for five light on a two foot track...

How high above the plants will they be? 5lights about 5 inches apart sounds like a lot of lights for that span.

..... I like the lower energy usage and heat output and I would like to expand my grow area without killing my electric bill.

I agree, I'm with you. For the winter I'd like to move the small seedlings into my house, have a new area to use but it would have to be totally under lights so I'm thinking this would be a good option.

 

[keithrs]

Anyone here have any thoughts on T-8 LED lamps? I also saw a mix of LED T-8 and HO T-5 in the same fixture at the hydro store a few days ago.

http://www.sunlightsupply.com/p-14182-agroled-t8-led-tubes.aspx

 

[cnycharles]

interesting, never heard of these. what is light output in comparison to a standard t-8 bulb?

 

[keithrs]

The LED's in the link are about half the lumens of a 32w T-8, but I have seen LED's in 2800 lumens on a 4' tube with different color ranges. I'm not sure if LED's produce the same colors the way HO T-5 or T-8 would? I'm sure Lanmark, Ray or some else has better knowledge on grow lights then me.