Switching to led's

[Aquii Finn]

Hello, please for some advice. I am currently growing cattleya's, cattleya seedlings and paphs mostly, under a 1000 watt halide fixture. (w an agrosun bulb)...it works well but is really expensive at 150 a month in juice, running it 12 hrs a day..it covers roughly 8"x 8". I am relocating, and my new grow space will be about 3' x 10'. Can someone name a few suitable led replacements to look into please to replace the 1000w halide. I may have to use a few..Ive read some orchid growers use much less wattage on their bulbs when switching to led's from 1000w, but not from someone successful with cattleya's...And are there any fixture designs for a long & skinny grow-space? Please for any links or ideas ...Thank you

[raybark]

There are MANY possibilities here. Because they generate so much less heat, you can keep the LEDs closer to the plants, "concentrating" the light, so they get as much as they need.

Are you a D-I-Y person, or prefer to buy off-the-shelf units? Something in between maybe?

There are LED COB (chips on board) kits that allow you to configure pretty much anything you want, and there are plug-and-play fixtures of all sorts, but I lean toward residential, outdoor spot- and floodlights made by Cree. A 18w, 40-degree flood puts out LOTS of light and only costs $13. Add a $10 lamp holder, and you have a great, easy-to-position light source. For a 3'x10' area, I'd guess that a half dozen would be more than adequate, so that would be under $150, repositionable for the needs of the specific plants, and only consume 108 watts.

[Aquii Finn]

Thank you for the info, i may build them. I'm not sure, its difficult finding info what led wattage is enough light to bloom cattleyas or what is equal to the 1000w halide...and taking my trusty footcandle meter around town to test is apparently ineffective with led's....hopefully ill lock horns with a cattleya grower who recently converted from 1000w halide system to led's....

[raybark]

Most of HID energy is wasted as heat, and I imagine the lamp is quite a way from the plants. What are the foot-candle readings you're currently growing under? If you divide that by 5, that's be pretty close the the PPFD you'll want from your LEDs, or if you're going to compare to the maximum recommendations for a particular genus, divide by 10 for continuous, artificial lighting.

For example, we are often told "1000-1500 foot-candles" for phalaenopsis, with the sun intensity starting at zero at dawn, reaching that at noon, than fading to zero at dusk. If we estimate that curve as a triangle, its area is 1/2 base (hours) x height (max intensity), meaning the plant has received (for example) 1/2 x 12 hours x 1000 f-c = 6000 foot-candle-hours. To match that as a continuous intensity with artificial lighting, it's 6000 f-c-h/12 hrs = 500 foot candles, or a PPFD of 100 µmol/m²/sec.

[Aquii Finn]

Most of HID energy is wasted as heat, and I imagine the lamp is quite a way from the plants. What are the foot-candle readings you're currently growing under? If you divide that by 5, that's be pretty close the the PPFD you'll want from your LEDs, or if you're going to compare to the maximum recommendations for a particular genus, divide by 10 for continuous, artificial lighting.

For example, we are often told "1000-1500 foot-candles" for phalaenopsis, with the sun intensity starting at zero at dawn, reaching that at noon, than fading to zero at dusk. If we estimate that curve as a triangle, its area is 1/2 base (hours) x height (max intensity), meaning the plant has received (for example) 1/2 x 12 hours x 1000 f-c = 6000 foot-candle-hours. To match that as a continuous intensity with artificial lighting, it's 6000 f-c-h/12 hrs = 500 foot candles, or a PPFD of 100 µmol/m²/sec.

i was growing at 3500 footcandles at the begining of this year, and it generated a lot of sheaths and a 15 blooms, but the summer heat made me lower it to 3000 footcandles to avoid summer leaf burn....i have been studying led's for a week and know less about what might do well for cattleyas than when i
asked in 4 forums a week ago...either nobody grows catts successfully under led lights or they enjoy seeing people squirm and loose plants by experimenting like they had to...wonderful, i guess i should just buy something...

[raybark]

I don't know why you think folks cannot grow catts under LEDs. I have successfully grown and bloomed vandas under them. It's all a matter of photon flux. I dare say you could successfully grow and bloom catts under ordinary filament incandescent bulbs if you wanted to.

Personally, I think you're overlighting your plants if your 3000-3500 FCC reading is accurate; that's usually the recommendation for peak lighting at noon, not for continuous exposure. But ignoring that, your light levels are equivalent to a PPFD of 600-700 µmol/m2/sec.

If you look at a Sunblaster LED - they are a popular brand, but I have no experience with them - a single 48W, 4' strip has a PPFD of 242 µmol/m2/sec at 6" and 116 µmol/m2/sec at 12".

I would bet that a four-bulb fixture, positioned a 9"-12" above a 6' x 3' growing area, would be adequate, possibly left on for a couple of hours longer per day.

[Aquii Finn]

I don't know why you think folks cannot grow catts under LEDs. I have successfully grown and bloomed vandas under them. It's all a matter of photon flux. I dare say you could successfully grow and bloom catts under ordinary filament incandescent bulbs if you wanted to.

Personally, I think you're overlighting your plants if your 3000-3500 FCC reading is accurate; that's usually the recommendation for peak lighting at noon, not for continuous exposure. But ignoring that, your light levels are equivalent to a PPFD of 600-700 µmol/m2/sec.

If you look at a Sunblaster LED - they are a popular brand, but I have no experience with them - a single 48W, 4' strip has a PPFD of 242 µmol/m2/sec at 6" and 116 µmol/m2/sec at 12".

I would bet that a four-bulb fixture, positioned a 9"-12" above a 6' x 3' growing area, would be adequate, possibly left on for a couple of hours longer per day.

Thank you for the info. I have an expensive collection, 80 or so catts, and just don't want to loose them or any experimenting..i posted in 3-4 orchid growing under lights groups and forums, and yet to have a reply that anyone is successful blooming cattleyas with leds( 2 said they were with vandacious types, zero feedback on catts....once i find someone successful i may copy that setup...the sunmaster is lower than the hid, not sure if it would work...i know it would probably keep them alive, like most leds or lights, I'm wondering if they would flower them....

[raybark]

In order for a plant to grow and bloom, it must (among other things, of course) absorb a certain "volume" of photons. What that light source is appears to be less of a factor than the sheer number of photons they put out.

Your HID lamp puts out a ton of photons, but mostly in the blue end of the spectrum. Folks also successfully grow under HPS, which is mostly in the red end. When I started, I used 50/50 wattage-wise incandescent bulbs (red) and cold white fluorescent shop lights (blue). In LEDs, you can go with red and blue, or white, and as I have been saying over and over, as long as the photon flux and the duration of exposure are sufficient, you're golden.

[Aquii Finn]

In order for a plant to grow and bloom, it must (among other things, of course) absorb a certain "volume" of photons. What that light source is appears to be less of a factor than the sheer number of photons they put out.

Your HID lamp puts out a ton of photons, but mostly in the blue end of the spectrum. Folks also successfully grow under HPS, which is mostly in the red end. When I started, I used 50/50 wattage-wise incandescent bulbs (red) and cold white fluorescent shop lights (blue). In LEDs, you can go with red and blue, or white, and as I have been saying over and over, as long as the photon flux and the duration of exposure are sufficient, you're golden.

Hid with a regular halide bulb would not flower many orchids. I stumbled upon agrosun bulbs which are full spectrum halide bulbs..It seemed to work well over the past year, where my new cattleya growths matched the previous greenhouse grown size bulbs. And had 25 out of 75 bloom and maybe 30 more currently in sheath...it is just expensive at 150 a month...i know leds put out a different color light, red and blue or white, which is supposed to be better for plants needs! why very few responders if any, have bloomed catts with led's is a mystery....i cant risk my expensive collection on different colored lights that have zero success rate to date..most experienced growers just graduate to greenhouses i guess....

[raybark]

The thing that I don't understand about your responses is the apparent assumption that because no one has responded affirmatively that they have grown and bloomed catts - specifically - under LEDs, that it is taking a risk to grow them that way.