LED lamp for growing in an office

[mSummers]

Can anyone recommend a LED lamp for growing orchids in an office environment? Most of the grow lamps in seeing are pretty expensive so I wanted to see if anyone here had used them before I get one.

I want to keep an orchid or two at work, maybe rotate them in and out when they're blooming. Most likely they will be oncidium or phalenopsis, so the plants are pretty tall.

 

[naoki]

How about something like this?

http://www.homedepot.com/p/Cree-90W...t-Bulb-BPAR38-1503027T-12DE26-1U100/205184898

This is a narrow beam (spot-type), so you can attach it far away. There is also wider "flood" style, too. I have used the wider flood style, and it gives 350 micro mol/m^2/s of PPFD and 1870fc at 12" (this means quite a lot of light at this distance). It will cover a couple plants easily. For Phalaenopsis, you'll need to place it further away or use a smaller bulb (something around 10W).

Or wal-mart may have something better in their "Great Value" line. I haven't checked their PAR38 flood, but for the A-type bulb (the round one), the efficiencies of non-dimmable ones are pretty high (for a screw in light bulb), and the price is good.

 

[Ray]

Hey, Naoki: when a lamp claims a 45° beam spread, is that the total spread or from the central axis, meaning 90° total?

 

[naoki]

Ray, I think that it is the total spread. I don't know the exact definition of the "beam spread", though. Some of them seem to use 50% of the max (central axis) as the cut-off.

I think that you are wondering why it gives high PPFD, and as you suspected, it is from the narrow beam pattern. So for Phals, something like Ray's LED (ink here) could be better (wider spread, more homogeneous light).

The Cree PAR38 (or most of LED screw in bulbs) isn't particularly efficient (91lm/W). But for a couple plants, I guessed that the efficiency wouldn't be a priority.

 

[Lanmark]

I'm quite curious about this lamp on Amazon (link below). The specs they provide seem to be impressive, but, in all honesty, I'm totally lost when it comes to micro mols and PPFD values and what they mean in real life. For example, what PPFD does a Phalaenopsis need? What PPFD does a Neofinetia need? I understand 1000-1500fc and 1500-3000fc, but that's about as far as my understanding goes.

http://www.amazon.com/dp/B00Z04X0XU/ref=wl_it_dp_o_pd_nS_ttl?_encoding=UTF8&colid=371UVBJLQCN9N&coliid=I3394JVOGWO8J

 

[gonewild]

PPF conversion table

http://www.apogeeinstruments.co.uk/conversion-ppf-to-lux/

 

[naoki]

I'm not familiar with the Osram unit. Some of the LEDs by Osram can be impressive. There is also something similar:
http://www.firstrays.com/cart/Lighting/Philips-GreenPower-LED-Deep-Red-White-Flowering-Lamp

Total output of Osram is 18 micromol/s of PAR from 17W (PAR efficacy of 1.05 micromol/J). Philips is 20 micromol/s from 15W (1.33 micromol/J), but it seems 22 micromol/s from 18W (efficiency 1.222) in Europe. Slightly above 2 micromol/J is about the state of the art (or technology) at this point (e.g. the linear version of Philips GreenPower).

For Phal, maybe the discussion here may help:
http://www.orchidboard.com/communit...ys-led-lights-light-meter-measurements-2.html
I try to get 50-100 micromol/m^2/s for Phals, but others (including Ray) could grow well at 30 micromol/m^2/s. I'm going with 150-250 micromol/m^2/s for Cattleya.

 

[Lanmark]

For Phal, maybe the discussion here may help:
http://www.orchidboard.com/communit...ys-led-lights-light-meter-measurements-2.html
I try to get 50-100 micromol/m^2/s for Phals, but others (including Ray) could grow well at 30 micromol/m^2/s. I'm going with 150-250 micromol/m^2/s for Cattleya.

The discussion at that link is very helpful. Thank you.

 

[naoki]

Lanmark, actually, I thought about it a bit more. I personally wouldn't go with the Osram you linked. Even a household LED flood light bulb has a better performance and more output. For example, this Cree 3000K 16.5W flood (it comes in spot, too) is 1510 lumen out of 16.5 watt. Using the emission data of other Cree 3000K diodes, it emits 19.5 micromol/s of PAR, so the efficacy is 1.18 micromol/J.
In other words, the household LED bulb gives more photosynthetically relevant light with less energy and 1/2 of the price than the Osram. I think that Cree bulb isn't the most efficient household LED now (so you can find better one if you shop around), but I happen to use it.

Most people aren't familiar with how to gauge the photon efficiency, and the following may help. I mentioned 2.0 micromol/J is the current best efficiency of grow light (from commercial products). As another reference point, linear florescent light (e.g. T8, T5HO) is around 0.84 micromol/J. HPS is is around 1-1.15 with magnetic ballast, and 1.3-1.7 with electronic ballet. With LED growlight (e.g. blue/red, white/red), there is a huge variation. Some of them (probably most cheap ones) are as low as florescent. Only a few well designed ones can achieve > 1.5 micromol/J.