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 Post subject: T5 or LED's ?
PostPosted: Sun Mar 22, 2015 6:05 pm 
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Hi,
I've been growing my Phals under T5's ( 2 bulbs per fixture; 1 growth: HO 6400k & 1 bloom: HO 3000k) & think I'm getting pretty good results except that they put out a lot of heat especially in the summer - 85 to 90 degrees or more and that's with the air conditioner on! I think that's how I got Mites with the high temps & lower humidity. My orchid room is the middle spare bedroom which is also the warmest bedroom.

Some members of my orchid society have been growing their orchids under those new 4' LED tubes: Feit brand 3600 lumens, 38 watts for $40 in a shop light fixture (two bulbs per fixture). Using just one fixture for the Phals & 2 fixtures for orchids that require more light.

Costco was selling them but they're always out of stock when I inquire about them. What are your opinions on using the white LED's? Do you think they would burn the phals? Should I just keep what I got?
Do you think I could get more growth & bloom compared with the T5's?

Thanks so much for any input I hope I get!!


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 Post subject: Re: T5 or LED's ?
PostPosted: Sun Mar 22, 2015 9:56 pm 
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Hi Amy,
Take a look at this topic

viewtopic.php?f=8&t=16962&hilit=led+costco

I don't think LED light is bright enough to bring phalaenopsis to flower if that is the only light source.

Do you have a basement or are you able to summer your plants outdoor?

Peter

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 Post subject: Re: T5 or LED's ?
PostPosted: Mon Mar 23, 2015 4:46 am 
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Location: Burlington, Ontario, Canada
i grow almost exclusively under led and the answer to your question is a long one. my opinion is that most people are under the impression that all leds give off more light than t5s.
Since we are only refering to leds in the "white" spectrum it makes the comparison easier. t5 give 80-100 lumen per watt, low to medium quality led are 70-130.
so where am i going with this if you grow phal under 112watts of HoT5s dont expect to be able to grow under 40 watts of leds.

I personally grow under diy cree leds, ive slowly replace my 4 foot t5s with 40watt array in a four foot configuration

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 Post subject: Re: T5 or LED's ?
PostPosted: Mon Mar 23, 2015 6:22 am 
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Location: Oak Island, NC
I agree with TSOP. The output from an average T5 HO lamp and that of a good quality LED is about the same - roughly 90 lumens/watt.

A single 4' T5HO is a 54 watt lamp, and in the original post, Amy was using two bulbs - 108 watts total, so would need three of the 38W LEDs to match that. However, that's not the entire story, either. There are lots of variables to consider.

One of those is distance from the lamp to the plants. Because of the inverse-square drop-off of light intensity, reduced light output at the lamp can be compensated for by moving it closer. Another related one is the area covered by the light. I, for example, am successfully growing and blooming phals and paphs in an area about 18" square, 12" under one of the 13W LED lamps I have custom made for me. If I wanted to use my LEDs to replace Amy's T5's from about the same height as she is, and covering a similar area, I'd need need 9 of them.

Then one must also consider the spectrum emitted. A good 6500°K T5 HO plant light bulb has a spectrum intended for growing and blooming, so needs no supplementation (which is why they're preferred over ordinary household lighting bulbs). A typical white LED - again for household lighting, not plants - has almost all of its output in the blue and green part of the spectrum, where the human eye is most sensitive, with enough on the yellow/red end to keep it looking white. They look so bright specifically because they are "tuned" to do so (which is why I add red chips to my lamps, to give the plants what they need).

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 Post subject: Re: T5 or LED's ?
PostPosted: Mon Mar 23, 2015 7:11 am 
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So I best keep my T5"s!! Well, that's a lot of technical stuff!! I do have a basement but you never know if we'll get another flood or not!! I was actually going to try it but I'd have to keep the shelves off the ground about 2' with milk crates of something to that nature & just make sure all the power cords are mounted up the wall to the power. But, then it's ugly & cold in the winter. I would need to put a temp gauge down there to see what the low end would be. And I also have African Violets on a shelf & they rotted in the summer because of the central air conditioning!

I was wondering if the lower night temps in the basement would keep me from having to bring the orchids outside in the fall to induce spiking?

On the other hand, I could bring them outside in the summer till fall (after they get 2-3 weeks of 55-60? night time temps, but I thought because they're growing mostly in AAA sphagnum moss they might rot being kept too wet especially when it gets humid out and at night??? I have a awning that covers the whole patio - would just have to make a rack to hold them. They'd be on the east side of the house with no direct sun.

Decisions-desisions!!! Thanks!!!!


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 Post subject: Re: T5 or LED's ?
PostPosted: Mon Mar 23, 2015 8:13 am 
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Posts: 683
Location: Clackamas, Oregon
amyorchidbud56 wrote:
... I'm getting pretty good results except that they put out a lot of heat especially in the summer - 85 to 90 degrees or more and that's with the air conditioner on! I think that's how I got Mites with the high temps & lower humidity. My orchid room is the middle spare bedroom which is also the warmest bedroom.


Hello:

I also had some phals on a large light stand in what was supposed to be a guest bedroom. It didn't work out well, that bedroom was like yours - got hot in the summer despite good air circulation and the plants also got mites.

Do you have a room in the house where there is a larger volume of air than an enclosed bedroom? I was able to solve my problem because my husband's sisters wanted to come to visit to get the family's photos organized. It required that the plant room be turned back into a guest room.

Good thing for me as I really wanted to get all my orchids into the den/kitchen area of the house, we've got vaulted ceilings in there. My husband really couldn't argue about moving more orchids into the den since I was making room for his relatives to stay for a week!

The heat build up in the den/kitchen area is handled better because of the high ceilings. The air circulation is better too. I don't run fans in the winter, but I do in the summer when the AC is on - it is more for my comfort than the orchids.

Keep experimenting with your growing area. Eventually you will find a solution that will work with your home.


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 Post subject: Re: T5 or LED's ?
PostPosted: Mon Mar 23, 2015 12:40 pm 
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Posts: 93
Location: Fairbanks, AK, USA
I don't have the experience with Feit, but I agree with TSoP that cheap LED isn't so economical in a longer term. High quality DIY LED is great! I've been moving to mostly DIY COB LED (Cree CXA3070 and Bridgelux Vero 29, which are one of the best performance/cost) from T5HO. But I do have one area which uses household LED bulbs. I can flower and grow species Phals under household Cree 9/9.5W light bulbs from Home Depot (about 4 of them for 2x2' area).

With regard to the spectrum, I actually think that the spectra of white LED looks better than fluorescent light. I do use mostly 4000K and 3000K LED though. I have a few 5000K LED, which has fair amount of blue. These do work well, too. Ray, when you are looking at the emission spectra, the plot is frequently using energy (instead of number of photons) as Y-axis. So if you convert it to the number of photons emitting, the blue peak become smaller than the plot. Remember that a blue photon has more energy than a red photon, but for the photosynthesis, number of photons are the relevant part.

When you are comparing the lumen output of different types of light, you need to be careful. Here is a couple measurement of PPFD/fc:

LED:
Cree soft white 18W, 3000K: 0.18 micromol/m^2/s/fc
Cree daylight white 18W, 5000K: 0.15 micromol/m^2/s/fc

Florescent light:
Agrobright 24" T5HO, 24W, 6400K: 0.12 micromol/m^2/s/fc
Odyssea 24" T5HO, 24W, "Plant" light (purple one): 0.17 micromol/m^2/s/fc
GE Helical, CFL, 13W, 2700K: 0.13 micromol/m^2/s/fc

These measurements were taken from 12" from the source in the middle by Li-Cor LI-190 PAR meter and LX1330B lux/fc meter.

Since the household light manufacturers don't publish PAR data, so we have to compare the lumen output. But we should be aware that even if lumen/W may be similar, warmer 3000K LEDs can give 50% more light relevant for photosynthesis than 6400K florescent light. Footcandle or lumen values are good enough when I'm comparing the same type of light, though (e.g. 3000K Philips LED vs Cree LED).


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 Post subject: Re: T5 or LED's ?
PostPosted: Mon Mar 23, 2015 4:03 pm 
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There is a lot of research going on for growing "other" plants under LEDs with different blends of spectrums. I have seen some plants that require very high light do well under LEDs.

It would be interesting to for some experimentation to be done on both seedlings in flask and growing adult phals to see what combination works best and how much output is really needed.

One of the more interesting things about this approach is that you could easily design a circuit that lets you shift the how much red and blue light the plant is getting to further optimize for growth vs blooming.


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 Post subject: Re: T5 or LED's ?
PostPosted: Mon Mar 23, 2015 4:12 pm 
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Location: Burlington, Ontario, Canada
my only beef with research going on with the "other" plant is that it is leading the led light fixtures to be super strong and a tight focal point.

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 Post subject: Re: T5 or LED's ?
PostPosted: Tue Mar 24, 2015 7:16 am 
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Joined: Tue Mar 10, 2015 7:42 pm
Posts: 26
doreen wrote:
amyorchidbud56 wrote:
... I'm getting pretty good results except that they put out a lot of heat especially in the summer - 85 to 90 degrees or more and that's with the air conditioner on! I think that's how I got Mites with the high temps & lower humidity. My orchid room is the middle spare bedroom which is also the warmest bedroom.


Hello:

I also had some phals on a large light stand in what was supposed to be a guest bedroom. It didn't work out well, that bedroom was like yours - got hot in the summer despite good air circulation and the plants also got mites.

Do you have a room in the house where there is a larger volume of air than an enclosed bedroom? I was able to solve my problem because my husband's sisters wanted to come to visit to get the family's photos organized. It required that the plant room be turned back into a guest room.

Good thing for me as I really wanted to get all my orchids into the den/kitchen area of the house, we've got vaulted ceilings in there. My husband really couldn't argue about moving more orchids into the den since I was making room for his relatives to stay for a week!

The heat build up in the den/kitchen area is handled better because of the high ceilings. The air circulation is better too. I don't run fans in the winter, but I do in the summer when the AC is on - it is more for my comfort than the orchids.

Keep experimenting with your growing area. Eventually you will find a solution that will work with your home.


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 Post subject: Re: T5 or LED's ?
PostPosted: Tue Mar 24, 2015 7:09 pm 
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Joined: Thu May 03, 2012 6:18 am
Posts: 93
Location: Fairbanks, AK, USA
TxRobNLA wrote:
There is a lot of research going on for growing "other" plants under LEDs with different blends of spectrums. I have seen some plants that require very high light do well under LEDs.

It would be interesting to for some experimentation to be done on both seedlings in flask and growing adult phals to see what combination works best and how much output is really needed.

One of the more interesting things about this approach is that you could easily design a circuit that lets you shift the how much red and blue light the plant is getting to further optimize for growth vs blooming.


There are some studies with Hybrid Phals. Here is an example:

http://hortsci.ashspublications.org/con ... 3.full.pdf

I'm not sure if you can see the full document, but if not, here is the abstract:
http://hortsci.ashspublications.org/con ... 3.abstract

Phals are CAM, so it is a bit more difficult to study the photosynthesis. But this study showed that 185 micromol/m^2/s was the saturating point. So Phals can handle fairly strong light (full sun at noon is around 2000 micromol/m^2/s). As a side note, some paphs had saturating point around 100 micromol/m^2/s. But these saturating points are influenced by many other environmental factors.

Inside of flasks, it is a bit difficult because photosynthesis is not the only carbon source.

There are some research with monochromatic LEDs for horticultural purpose. It is interesting, but technology of white LEDs seems to be progressing faster.


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 Post subject: Re: T5 or LED's ?
PostPosted: Wed Mar 25, 2015 6:59 am 
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Joined: Fri Sep 17, 2010 7:52 am
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Location: Oak Island, NC
naoki wrote:
Ray, when you are looking at the emission spectra, the plot is frequently using energy (instead of number of photons) as Y-axis. So if you convert it to the number of photons emitting, the blue peak become smaller than the plot.

Thanks, Naoki.

Where can I find conversion factors?

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 Post subject: Re: T5 or LED's ?
PostPosted: Wed Mar 25, 2015 1:17 pm 
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Joined: Thu May 03, 2012 6:18 am
Posts: 93
Location: Fairbanks, AK, USA
raybark wrote:
Where can I find conversion factors?


I think this is the explanation, isn't it? I haven't taken physics for a long time, so I may be completely wrong.
http://www.pveducation.org/pvcdrom/prop ... -of-photon

I haven't done the conversion by myself, but I've seen other people digitize the emission spectra and convert it to number of photons. Then this can be used to calculate photosynthetic photon flux (PPF) and yield photon flux (YPF, which is adjusted for the photosynthetic action of "typical" plants). When you are looking at the white LED emission spectrum, I think the height of the blue peak becomes about 2/3 of the energy plot. I got an interesting spreadsheet doing this calculation from TyroneGenade (of SlipperTalk) who got the sheet from someone interested in planted aquarium lighting.


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 Post subject: Re: T5 or LED's ?
PostPosted: Wed Mar 25, 2015 3:16 pm 
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Joined: Tue Mar 10, 2015 7:42 pm
Posts: 26
peterlin wrote:
Hi Amy,
Take a look at this topic

viewtopic.php?f=8&t=16962&hilit=led+costco

I don't think LED light is bright enough to bring phalaenopsis to flower if that is the only light source.

Do you have a basement or are you able to summer your plants outdoor?

Peter


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 Post subject: Re: T5 or LED's ?
PostPosted: Wed Mar 25, 2015 3:51 pm 
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Joined: Wed Jan 14, 2009 8:25 am
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Location: Minnesota
I have no problem flowering my Phals under only LED light.


Sent from my iPad using Tapatalk HD


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