LED flat panel lighting question

[junglejim]

Is anyone using flat panel lighting to grow orchids? It maybe an option. I understand in 1-2 years metal halide and sodium bulbs will no longer be made. I grow in the basement with no natural light.

 

[ehanes7612]

where did you hear that? as of now , there is no incentive for pot growers to use anything but cheap metal halides and sodium bulbs ...and as long as there are pot growers (as well as non pot growing hydroponics),these bulbs will continue to be made ..because LEDs cant match them...you may have heard about cities changing to LED bulbs for street lights and are confusing the two uses(or the incandescent ban act does include one type of metal halide).there was an article in Orchids a while back about the effectiveness of LED 35 watt bulbs ..i forget who sells them .orchids by hausermann maybe

 

[junglejim]

When I was reordering bulbs that had dimmed from OL a couple of weeks ago. I was tempted to order another year's supply and asked how long will you be keeping these in stock? I was lead to believe they won't be made down the near future. Jerry said he would have them for probably 2 years. However most people are switching over to LEDs. That's why I'm looking into these. Menards carry them. A lot of light for little watts.

 

[junglejim]

What I was ordering was the high pressure sodium 400 watt Son T. That's how the conversation got started. Menards are now carrying flat panel LED lights and I would like a brighter light I think. These lights are now the "white light" and not the blue and red hues that some growers have been using.

 

[DavidCampen]

I understand in 1-2 years metal halide and sodium bulbs will no longer be made.

I find that hard to believe.

Also, HPS and MH are a bit more efficient at converting electric power into light useful for photosynthesis than are LED and HPS and MH cost _much_ less than LED.

 

[gonewild]

HPS and MH bulbs are what most warehouse and industrial complexes are lighted with and I doubt they will be switching to LEDs in the next couple years.

 

[MorandiWine]

David can you please expand on your statement about the efficiency of conversion for photosynthesis? Seems like a pretty bold statement since so many people have had great success (including myself) after switching from HPS, Halide and T-5 lights.

Not only do I use LEDS for orchid growing but I have been using LEDS for growing corals. The growth rates are exponentially higher with LEDS than with the other lights. If the lights are poor at energy conversion then the organisms grown under them would not thrive, right?
An example of growths with Paphs and LEDS....I bought a couple stonei seedlings, one went in a GH and one went under LEDS. The GH seedling has grown a little and sent out a single new leaf whereas it counterpart has sent out four new leaves and a new lead. Almost the exact same with hangianum that was bought as seedlings four months ago. Thriving under LEDS.

Tyler

 

[DavidCampen]

David can you please expand on your statement about the efficiency of conversion for photosynthesis? Seems like a pretty bold statement since so many people have had great success (including myself) after switching from HPS, Halide and T-5 lights.

Not bold at all. I can give you quantitative values for the PAR (Photosyntheticly Active Radiation) flux from different light sources. I will go look up the references where I have posted them on OrchidBoard.

Not only do I use LEDS for orchid growing but I have been using LEDS for growing corals. The growth rates are exponentially higher with LEDS than with the other lights. If the lights are poor at energy conversion then the organisms grown under them would not thrive, right?

I did not say that they were "poor at energy conversion". I said "HPS and MH are a bit more efficient at converting electric power into light useful for photosynthesis than are LED". T5 fluorescent, LED, HPS and MH are all within (much) closer than a factor of 2 of one another in efficiency.

An example of growths with Paphs and LEDS....I bought a couple stonei seedlings, one went in a GH and one went under LEDS. The GH seedling has grown a little and sent out a single new leaf whereas it counterpart has sent out four new leaves and a new lead. Almost the exact same with hangianum that was bought as seedlings four months ago. Thriving under LEDS.

Then the same would have happened using T5 fluorescent instead of LED.

I am using 200 watts (true watts, not the marketing hype equivalent watts that you see in most LED advertisements) of LEDs as supplemental lighting and I have not seen any magical effects.

 

[DavidCampen]

Here is a post with PPF values for various light sources.
http://www.orchidboard.com/communit...eresting-links-about-lighting.html#post554104
"using Philips data we have these PPF (micromoles per watt-second) values for different light sources:
1.2 - Fluorescent
1.8 - Deep Red LED
1.9 - HPS "

 

[Garr]

To the best of my knowledge, LED fixtures have the highest energy to PAR light conversion rate (efficiency) available of all the lighting options currently available. I have four complex PAR spectrum LED fixtures each drawing 420 watts of current with PPF values of 400 under the center of the light at a ride height of 48". This is enough light to bloom P. randsii, P. phillipinense, P. rothschildianum etc. As an added benefit, the fixtures produce little heat as the energy conversion is so efficient. BTW, it's incandescent lamps which are slated for withdrawal from sale and not HPS or MH.

 

[DavidCampen]

To the best of my knowledge, LED fixtures have the highest energy to PAR light conversion rate (efficiency) available of all the lighting options currently available.

The data I gave in the post above contradicts your statement.

with PPF values of 400 under the center of the light

The flux under some small area does not mean anything. For the number to mean anything it needs to be the integrated value over the illuminated area. Also you need to specify units, PPF is not a dimensionless number.

 

[Garr]

The data I gave in the post above contradicts your statement./

Philips own data indicates these PPF (micromoles per watt-second) values for different light sources:
1.2 - Fluorescent
1.8 - Deep Red LED
1.9 - HPS
I won't disagree that when comparing deep red LED light to HPS, the conversion efficiency is marginally higher. Having said that, the spectral output of HPS is relatively the same from lamp to lamp. The conversion efficiency of LEDs is closely related to their spectral output. Some wavelengths are more efficient than others at energy conversion. Because LED fixtures are a proprietary blend of LED chips of different wavelengths, energy to illumination conversion efficiency is dependent on which fixture from which manufacturer you are evaluating. The spectral output of HPS tends to be 'notchy' in the 400nm-540nm area resulting in under illumination in specific areas. The LED orbs can be blended by choosing different chips resulting in a more uniform array of frequencies and intensities. Some manufacturers include controls allowing the user to increase and decrease red and blue spectrum light. I bet that if you were to put a reasonably accurate ammeter on the input current, you would see variations in current draw as you played with the controls. All this to say that comparing HPS efficiency to LED efficiency is really comparing apples to oranges. Depending on chip efficiency and spectral array make-up, one can be more energy efficient than the other. Having compared all the options out there, I have chosen the LED route for reasons of color balance, 50,000 hr lifespan, cool running, light distribution over footprint and cost of ownership over service life. Having grown orchids in sunlight, under fluorescent lamps, HID and HPS, I will stay with LEDs.

The flux under some small area does not mean anything. For the number to mean anything it needs to be the integrated value over the illuminated area.

Absolutely correct. The mean illumination over a defined area is mathematically correct when comparing specifications from fixture to fixture. This is a point of contention I have with several manufacturers who just don't provide adequate information about their products. The light intensity tends to fall off exponentially as you move away from center. An accurate light footprint would go a long way to helping the user plan the geometry of the grow bench vs. fixture ride height.

Also you need to specify units, PPF is not a dimensionless number.

PPF or Photosynthetic Photon Flux is defined as µmol photons/m2/second so it is anything but dimensionless. I use a Li-Cor LI250A photoradiometer. Yes, any given reading is just in that spot in three dimensional space. One needs to take several readings in several different axes in order to more accurately establish average illumination.

A quick bit of unsolicited advise to Paph growers contemplating a switch to commercial intensity LED fixtures. These lights are bright...intensely so. They are an order of magnitude brighter than fluorescent bulbs. The human eye is poorly equipped to accurately judge the intensity of PAR light as are most light meters! The pink/purple light that they cast is deceptively dim. For the plants however, it is anything but! Underestimating how bright the light is and moving the plants too close to the fixture will result in light scorched leaves in fairly short order. If you don`t have an appropriate meter, start out very conservatively and watch your plants closely to avoid heartbreaking consequences.

I have mapped my own grow room for light intensity and have located plants based on this map. De-flasked seedlings all the way at the edge of the light footprint followed by P. mastersianum, P. gigantifolium gradually moving towards the center where P. drurii and P. phillipinense among others do well.

 

[DavidCampen]

PPF or Photosynthetic Photon Flux is defined as µmol photons/m2/second so it is anything but dimensionless.

Exactly, yet you gave a meaningless value for a measurement at a single point

I use a Li-Cor LI250A photoradiometer. Yes, any given reading is just in that spot in three dimensional space. One needs to take several readings in several different axes in order to more accurately establish average illumination.

One needs to take readings in mulitple locations for the value to have _any_ meaning.

A quick bit of unsolicited advise to Paph growers contemplating a switch to commercial intensity LED fixtures. These lights are bright...intensely so. They are an order of magnitude brighter than fluorescent bulbs.

If you are claiming that LEDs are an order of magnitude more efficient than T5 fluorescent in converting electrical power into PAR then that is an absurdly inaccurate statement.

 

[Garr]

Exactly, yet you gave a meaningless value for a measurement at a single point


One needs to take readings in mulitple locations for the value to have _any_ meaning.


If you are claiming that LEDs are an order of magnitude more efficient than T5 fluorescent in converting electrical power into PAR then that is an absurdly inaccurate statement.

What I said was that They are an order of magnitude brighter than fluorescent bulbs...not more efficient.

 

[DavidCampen]

What I said was that They are an order of magnitude brighter than fluorescent bulbs...not more efficient.

So that statement then has nothing to do with their effectiveness at converting electrical energy into PAR. I just wanted to clarify that.

Yes, an LED may be emitting on the order of a watt of light from an area 1 millimeter square so the amount of light emitted per unit area (brightness) is greater than a fluorescent light but the amount of electrical power required to produce 1 watt of light is about the same for LED or fluorescent.

 

[Garr]

So that statement then has nothing to do with their effectiveness at converting electrical energy into PAR. I just wanted to clarify that.

Yes, an LED may be emitting on the order of a watt of light from an area 1 millimeter square so the amount of light emitted per unit area (brightness) is greater than a fluorescent light but the amount of electrical power required to produce 1 watt of light is about the same for LED or fluorescent.

As a stand alone statement, you are absolutely correct. As far as I know, the state of the LED chip technology is now achieving illumination levels of well over 200 lumens per watt input. This is strictly for the chip itself. What confounds the situation is that this same chip requires a circuit board where the LED chip is housed along with the other chips, a driver that rectifies and transforms current coming from the wall, optics that direct the light to the right place and a housing that dissipates the heat generated by the fixture. Efficiency losses along the way in the form of heat conspire to reduce this energy conversion. Fluorescent technology has been steadily improving to the point where now the two technologies are about neck and neck when you look at the whole fixture in both cases.

Given that the efficiency of the two technologies are comparable, the grower needs to evaluate all the ancillary factors when investigating lighting options i.e. initial light intensity, decay of light intensity over time, spectral output, heat generation, light distribution over footprint, maintenance costs, ease of installation and how much room the fixture occupies overhead (this is an important consideration when using the light to augment natural light) among others. As this is a rapidly evolving technology, some LED fixture manufacturers will offer an upgrade package to the newer technology as it becomes available ensuring that the customer isn't left behind as a superior product make the current technology obsolete.

This debate will continue to rage for some time. No doubt over time, fixtures will become smaller, more efficient, spread light more evenly over the footprint and so on. For the time being, I've made my choice and am very pleased with the results.

David, on another subject, what are you growing and how?

 

[junglejim]

Back to my original thread. Is anyone out there using flat panel LED lights for growing orchids? This would be sole light source in a basement.

 

[DavidCampen]

I have about 160 orchid plants, I focus mostly on species and I have a lot of cattleyas. I have about 40 different species of cattleya and also laelia, encyclia, epindendrum etc. I have about half a dozen paphiopedilum species - henryanum, venustum, delenatii, barbatum are the ones that I can remember off hand. I also have a few each of gongora, stanhopea, angraecum, phalaenopsis, dendrochilum etc.

These links have a couple photos of my orchid room. I started constructing it about 2 years ago. These photos were taken about a year ago, I have a lot more plants now.
http://www.orchidboard.com/communit...essure-1000-psi-fog-systems-3.html#post506771

http://www.orchidboard.com/communit...s/60598-homemade-led-lightbar.html#post505567

 

[junglejim]

Thanks David, nice pics. I'm interested in the flat panel LED's lights that emit white light, not the red,blue, purple hues. Lowes and Menards are now carrying them. They are also called LED plant panel troffers. They are used for recessed lighting. Orchids Limited started carrying them . These lights area "spin off of flat panel TV's " according to my initial conversation with OL, where I got first interested in replacing sodium and metal halide bulbs.

 

[Garr]

Back to my original thread. Is anyone out there using flat panel LED lights for growing orchids? This would be sole light source in a basement.

Jim,
My grow room is in a two car garage and uses LEDs as sole source light. Each fixture has 240 - 3 watt LEDS in 12 orbs drawing 360 watts of current. These fixtures are designed for commercial greenhouses and measure 21"x16"x3". Is this what you mean by flat panel?