Switching to led's

[Mike H]

If your an AOS member you can view this article in Orchids magazine.
https://secure.aos.org/digital-libra...efault.aspx#48

---------- Post Merged at 09:29 AM ----------

The author says he has successfully flowered Cattleya as well as other orchids under LED.
If your not an AOS member JOIN! (I have no affiliation with AOS)

[Aquii Finn]

Photosynthetically active radiation (PAR) quantifies photons in the wave length range that supplies photosynthesis. You need a PAR meter to measure this way. A standard foot candle meter usually measures additional wavelengths, so the reading isn’t as precise for what plants specifically need. However, the ratio of 5:1 foot candles to PAR peak photon density may be a rough approximation. If 300 peak photon density is the most that you should need for constant lighting over the course of a day, that would be roughly 1500 foot candles. I think it is important to remember that many orchids are sensitive to day length and giving them more or less day length than they are genetically programmed to want may inhibit best growth or blooming. The range from 11.0 - 13.0 day length will satisfy any Cattleya. An indoor light grower can give this exactly. A green house grower in northern latitudes is mostly stuck with long day length in the summer. In the winter, they can give supplemental light to keep to a minimum of 11.0 hours.

The daily light integral for my Cattleyas varies from about 10 to 12 moles/m2 over the course of the year. This is consistent with a few other reports of PAR light exposure for higher light orchids in green house conditions. Ray’s calculations work in an indoor plant room with LED lights.

Please for a little more help. I am understanding the light levels plants need averaged out thru the day, and par light is different on light meters, that a decent par meter will cost about 150.00...but the choices on led models is confusing. I am going to have a 3' x 12' grow area full of bs catts, and i figure i should get 4 lights, one to cover every 3' x 3' area..possibly 500w-1000w each???? The prices vary, from many that are $75 to $150, and some that sell for $700 each unit?????....times 4 that's expensive..And some are boxes or panels full of small blue and red lights only, some have small blue, red and white lights stating full spectrum. and there are large white led spot light looking lights with cree bulbs, advertised as grow lights...(I think i want whitish looking light for aesthetics, as its in my living room).. knowing there are a lot of cheap crappy ones out there that don't work, its hard to try to find a good price on something that actually works,,,can someone please name a few reputable brands or models that might suffice for growing catts in a 3' x 12' area...

[Mike H]

Do your research so you understand what your getting, then research it a bit more.
Then track your setup and share with us all your results.
Most of all enjoy the journey.

[Terryros]

I start with the assumption that you will use natural white or true white spectrum bulbs. These work and let you see plants and blooms in reasonably true colors.

LEDs may be bulbs or tubes. The bulbs may have focusing lenses ranging from 30 degrees up to 120 degrees. A non-focused bulb would be about 180 degrees. A more focused bulb keeps more of the light on your plants and lets you be higher above the plant. Tube fixtures may be focused or may have a reflecting surface that puts some light back on your plants. What comes out of a bulb or tube is only the start; what matters is what gets to the plant.

For my best growing area for mature, unifoliate Cattleyas, I have four 20 watt, 60 degree focused ALT bulbs producing 1550 lumens each. These are spaced equally over a growing area that is 22 inches wide and 4 feet long. The bulbs are 9 inches above the top of the leaves. You can find more efficient bulbs (and less expensive ones) but the lensing and heat dissipation of these bulbs is great. This positioning produces about 300 micromoles/m2/sec in the center at the top of the leaves. Obviously, lower down and out to the side, the intensity is less, so the average the plants are getting is lower than 300.

Without a PAR meter, you would have to go with the 1:5 conversion from foot candles. With any bulb or tube, I would try and get just one and measure under it to see how high you need to be from the leaves and how much area the LED source will cover. Don't buy a bunch of lights and then find out that they don't work.

[Dorsetman]

I am very late looking at this thread - unusually I have an hour with nothing to do (!)..
But with a long narrow growing area, why not use a light track, and send your single lamp back and forth ? You then use much more light than you would want, but average it out because the light comes and goes. I have used this system - yes on my cats - for several years now. The lights are in fact as near to the plants as I can get them - those with tall spikes ( schombocatts and L.autumnalis etc ) have to be placed carefully so that they are not chopped off by the lights.
I have a large growing space - maybe almost 30 feet a over 5 feet , and I have several tracks running across this space, in fact 2 metre ( 6 ft 8inch) tracks, so that the light also reaches beyond the growing space, lights up the paths at either side, and also the front part of the two side benches.. ( A 30 foot track would be an impossibility - elec' supply connections for one reason ). My lamps are all 600 watt "dual spectrum" Bayer bulbs, apart from one 240watt LED array.

[Aquii Finn]

I went with 2 amare sp 400's and a single cobb led in between, to cover the 12' x 3' area. The single cobb should be good for seedlings and paphs i hope...with the catts under the amare's on both ends...plenty of light, no burnt spots yet....I do have a cat eldorado for the first time producing 2 buds under these leds...so happy for that, but it has only been 4 weeks...i hope it is an eldorado actually and fun to see the color variety if it is...

[Dorsetman]

Eldorado is, I believe, now wallissii - the old rule of priority. Pity, I think eldorado a much more romantic name.
One of my favourite species - L am on the lookout for varieties . I have v.coerulea on order at present.

[Masaccio]

Could I add another question here, that could be relevant to a standard-sized cattleya grower? That would be the rate of fall-off from LEDs, which, according to my PAR meter, seems sharp. Ray, I know you would know, or have good comments on this (and thank you on my own behalf for the great information you provided in this post). Aquii Finn, I too have just converted to LEDs and used to grow standard cattleyas under HID - mine was only 500 watts (250 MH + 250 HPS) all the time. I share your hesitancy and concerns about LEDs. I've just started a collection for my new LED setup, and in the cattleya department only have a seedling C. trianae, and a C. violacea, both of which are doing just fine under ordinary outside spotlights (26 watt 250 watt eq). The trianae is rooting like crazy and re-established itself post-repotting in no time. So I would say yes, enough light for cattleyas theoretically, but with the caveat of falloff making standard cats more of a challenge. I hope to hear what Ray has to say about this because I have no experience with taller plants as yet. Thanks.

Oops. I didn't notice several pages of great responses before I posted my question. Great thread!

[raybark]

Light is light. No matter how it is produced, the "fall-off rate" is the inverse-square - 2x the distance = 1/4 the intensity, 3x = 1/9, etc. However, the configuration of the lamp and the reflector all make a difference in what gets to the plant, meaning there is no easy way to calculate that for comparative purposes.

For example, a 2' T5HO fluorescent and a LED floodlight may have the exact same initial light output, but the former is spread out over two feet of length and radiates from the entire surface of the tube, with some of the light projected directly at the plant, some scattered sideways, some reflected down to them, and some reflected back into itself, so is lost. The light from the LED spot, on the other hand, emanates from a very small area mostly facing the plants, and is enclosed in a far more efficient reflector package, so far more of the light energy actually gets to the plants.

I suspect that the reason the drop off seems greater with the LEDs is because there is far less scattered light for your meter to capture than there was with your HID setup. Personally, I'd set the height based upon the measurements near the tops of the plants. Your multi-lamp setup ought to be great for complete coverage.

[Masaccio]

Cool. Thank you, Ray.