Rays LED lights and light meter measurements

[smokinjoe52]

My first post on the OB other than my Intro. I have been designing and building a small grow chamber for my orchids. I have decided to utilize just one 27" x 18" shelf for about 6 or 7 orchids. I have 6 Of Ray's LED lights that can be angled and adjusted in several different ways. I decided to purchase a fairly inexpensive, but highly rated light meter on Amazon.

Ray's LED lights seem to be nicely weighted towards the blue end and the red end. Looking at the manual for the Light meter, it seems that it is NOT, by a long ways, linear over the visible spectrum. Please see .pdf attachment.

I was going to use the standard information for light levels found in many places with orchid light info.

900 - 1500 lumens for Phals
1500 - 300 for Onc.

So, am I measuring WAY less light for Ray's LED lights than what the orchids are actually getting?? The meter reads about 600-700 lumens over the Phal, and 1000 or so over the Onc.

Can anybody on the board correlate light meter readings with Ray' Leds?

It would nice to have a multiplier for the meter readings, correlated to Ray's lights.

Any information regarding this would be appreciated.

I wanted to utilize only Ray's LEDs for their low heat output, and the ability to have 6 of them that are fully adjustable. Initial reading brought the in-tent ambient of 68 degrees to only 73 when I turned on 4 lights and zipped up the tent.

Thanks in advance for any information on this subject.

Joe

[estación seca]

Read more in the forum here about growing plants under lights. Your questions will be answered there. It will take a long time to read and understand. Older measurements designed for other kinds of lamps are not applicable to LEDs.

LEDs emit photons in a very narrow frequency range. They do not emit at most visible frequencies the way incandescent or fluorescent lamps do.

Commercial growers select LEDs with emissions spectra near optimum for chlorophyll absorption. This light is pink and blue and unpleasant to most people, but there is no wasted energy producing photons the plants won't use.

[smokinjoe52]

es,

I believe I have read and understand the spectrum and use of LED lamps such as Ray's. I also understand all of your points.

What I have searched for and not found on this forum is the correlation between suggested lumens for various orchid types and Ray's LED bulbs. I don't believe it is 1:1.

If that information is already posted on the forum, I would appreciate a link, because I can't seem to find it.


Joe

[naoki]

Joe, is this the kind of you are looking for:
Brightness with LED Lights

post #18 has PPFD. If you multiply your fc by 0.14, you can get PPFD (in micromol/m^2/s). Phals can be grown around 50-100 micromol/m^2/s (with 12-13 hours/day). I target around 100 micromol/m^2/s.

lux and fc aren't a good measurement for plants, and PPFD isn't perfect, but it is much better (and the standard for the plant science). 1000 fc of sun light contains 200 micromol/m^2/s. But those recommendation you quoted is for the peak (i.e. noon time) intensity in the greenhouse. With continuous light, you can get away with much lower light.

[smokinjoe52]

Thanks Naoki,

Just the info I have been trying to find. I will now take a look at what my meter reads at a distance of 12" under a Ray's led light in a dark room, and go from there. Knowing what the output should be from the lamp, I can calculate my own conversion factor...even though I really don't need to convert it to anything. Just need to know what the meter reading is for a known source at a known distance at a known output.

Keep in mind that my objective is not to measure specifics, buy just to stick the meter by a newly placed plant, see a number, (doesn't matter what the units are) and determine if it is "in range" for that specific plant. That is all I really want to know.

[smokinjoe52]

My grow chamber is now up and running. I thought I would share my little project in case an OB member would like to duplicate it or maybe use some of the components. I can provide Amazon links to most parts if anybody is interested.

My objectives:

Build an environmentally enclosed system to house about 6-7 orchids during the growing season. I wanted to control temperature, humidity and light. I also wanted less (watering) maintenance since we travel quite a bit so I am in the process of converting to SH.

The project pics are attached.

I used an inexpensive greenhouse from Amazon. I only wanted 1 grow shelf, so left 1 "floor" out of the build. Spare parts are shown on the floor. I used some adjustable lights that fit perfectly on the frame of the greenhouse. The third floor center rail was omitted as this is where the lights shine through. No big deal if it was included.

The bottom shelf is used for a humidity tray, a 12v IP55 rated (dust and humidity) fan, and a seed germination pad for newly transplanted orchids. I did put a piece of thick black plastic on the bottom shelf for more support.

Second floor are where the transitioned (from SH) plants are located.

Third floor empty and no center rail.

Fourth (top) floor now houses another fan pulling air up from the orchid area. It also contains an old Radio Shack remote temperature and humidity controller so I can monitor from the upper level of the house.

The entire green house sits in a plastic tray meant for portable dog kennels. (It JUST fits)

So, I fired it up.

The usual temp in the room was 68 degrees. The humidity was 34%

I then turned on 4 lights, both fans, filled the humidity tray, added 4 orchids all in SH saucers.

After running 24 hours, daytime temp stabilizes at 73 degrees, +- 2. The humidity holds fairly steady at around 65%. Maybe +- 5%.

I am getting 2 more LED lights (6 total) so expect a few more degrees rise in daytime temperatures. The room is in the lower level of a walkout ranch, so temps. in the summer time will rise less tan 5 degrees.

It has been running for 5 days now, and it seems to be working just as I had hoped...which usually doesn't happen with most of my projects.

Right now I plan to keep maybe 3 Phals and 3 Onc. so am trying to determine how to utilize the lighting, and if I will need any more for the Onc.

BTW - I measured one of my lamps in a dark room, on a non-reflective surface, 12" from the top of the light sensor and measured 3400 lumens.

As I live in the Midwest, it appears now that my orchids will no longer need to live in 25 - 30% humidity, low temps., and too little light in a house surrounded by trees!

Most surprising, and most welcome is the fact that 6 - 13 watt led lights only bump the temp by 5 degrees (4 lights) and maybe 7-8 degrees when I add the last 2 lights. I was afraid the temp. would be too high in the daytime.

Any comments, questions, suggestions etc. welcomed.

Joe

[Motheroftwins]

Where did you buy the fixtures for your LEDs? I have the LEDs from First Rays but haven't found satisfactory fixtures.

[smokinjoe52]

These are the ones I used:

Amazon.com : LimoStudio 2 x New Studio AC Socket Light Stand Mount Umbrella Holder, AGG428 : Photographic Lighting Umbrellas : Camera & Photo

Keep in mind that they are designed to slip onto a 5/8" outside diameter tube. I am not sure how you would mount them otherwise. They are not ceramic, but at 13 watts, they don't even get warm.

Also, for headache prevention, these WILL NOT work.

Amazon.com : 100W Ceramic Heat UV UVB Lamp Light Holder for Chicken Brooder Reptile Basking : Pet Supplies

Ray's bulbs will not screw into the fixture far enough to make a connection. The black housing extends too far out from the socket.

Joe

[Jayfar]

Originally Posted by Motheroftwins

Where did you buy the fixtures for your LEDs? I have the LEDs from First Rays but haven't found satisfactory fixtures.

These dirt cheap fixtures from Ikea (TERTIAL work lamp) work well for me. You just leave off the shade bell.

TERTIAL Work lamp - IKEA

[billc]

Originally Posted by Motheroftwins

Where did you buy the fixtures for your LEDs? I have the LEDs from First Rays but haven't found satisfactory fixtures.

I went to a local Tru Value hardware store and got a 2 prong light bulb adapter and plugged it into a 3 way plug adapter. Tied it up to the shelf above and 3 of Ray's bulbs cover a 18 in X 48 in shelf just fine. 22-24 in distance from plants for 9-10 hrs seems to work fine for paph and phals. The phals leaves are a tad purplish but they flower just fine.

Bill