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Posts: 1,845
Reply with quote  #21 
At the risk of showing my ignorance of the subject, how about led rope lights like this or led Christmas lights?  Think they would work and how do they compare in price?


actually these strips look real promising and seem to be a good price. (and run off 12vdc)



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Posts: 283
Reply with quote  #22 
Hello all
Firstly thanks for the help and input.Thats an interesting insight regarding the uv Keith.
No worries Dan your heading in the same direction i was anyway.As in is how can this be done cheaper?

Heres some info i found online with a list of possible bulbs that may be useful.I didnt post a direct link because it was a different type of growing forum.Its a start anyway and it dont bother me much if as long as it it provides me with some of the info i want.
A similar led lighting set up to the clip was listed ,so i thought it relevant.The lights shown in the clip were (50-400 μmol/s/m2)  (36 W or 58 W).The list below has a lower wattage(19.5 W , 18 W and 16 W so its safe to say they are different models.

Here is a part of the post.

"Basic off-the-shelf LED Lamps if chosen carefully will perform.

Due to places like Menards, Lowes, Home Depot, and many other retailers have driven the LED market to produce affordable LED LIGHT BULBS.

Take a look at the LED PAR38 lamp/bulb.

4 or 5 of LED PAR38 lamps/bulbs will replace a 70 watt HPS/MH in light output for smaller grow areas.
1 LED PAR38 lamp replaces a 23 watt compact flourescent bulb.

LED PAR38 Lamps provide a full and continous light spectrum unlike flourescent lamps and HID lamps (ie. mercury/sodium emission lines).
They produce quite intense light and are directional without reflector, all light goes down.
They do lack in the deep/far red specturm (ie. ~655nm and ~737nm) unless you use something like the Philips Greenpower LED or 100 Watt red incandescent flood on a dimmer.

Some PAR38 LED Flood Light Bulbs that produce good light for plant growth especially in small areas:

Ecosmart 24 watt LED Flood 3000K (1300 Lumens)

Feit Electric 23 watt LED PAR38 3000K (1400 Lumens)
Feit Electric 23 watt LED PAR38 5000K (1400 Lumens)

GE 26 watt PAR38 3000K Flood (1500 Lumens)
GE 20 watt PAR38 2700K Flood (1000 LUmens)

Lighting Science Definity PAR38 Hi-output 24 watt CW-5000K (1460 Lumens)
Lighting Science Definity PAR38 Hi-output 24 watt W27-2700K (1250 Lumens)
Lighting Science Definity PAR38 Hi-output 24 watt WW-3000K (1300 Lumens)

Philips 19.5 watt Ambient LED 5000K (1300 Lumens)
Philips 19.5 watt Ambient LED 3000K (1200 Lumens)
Philips 19.5 watt Ambient LED 2700K (1100 Lumens)
Philips 18 watt Greenpower LED white/deep red (22 mmol/s)
Philips 18 watt Greenpower LED white/deep red/far red (18 mmol/s)
Philips 16 watt Greenpower LED far red (12 mmol/s): looks very dim because our eyes don't see this light well.

Slyvania ULTRA 24 watt PAR38 3000K Flood (1300 Lumens)"

Regards Mattie


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Posts: 283
Reply with quote  #23 
Hello all
I changed the title of the thread because i though it was a better description.
I ended up looking at the 50-400 μmol/s/m2  on the specs for the LED shown in the clip i posted ,to see if i could convert photons into a lumen value, for bulb comparison purposes.
I could not find a converter for LED(I realize this is making the results inaccurate) i choose the plant growth florescent option in the drop down menu and converted to 400 μmol/s/m2 (photons to lux) which gave me a value of 13200 lux

From here i used another converter for lux to lumen and used .3 square meters as an example surface area. http://www.rapidtables.com/calc/light/lux-to-lumen-calculator.htm

I ended up with a value of 3960 lm which is a lot higher than the other bulb lumen values, there is a size and watts difference here too so maybe its kinda(great scientific term lol) right.Only on the lower scale of 50 μmol/s/m2 do i end up with 1650 lm if i input a 1m2 surface area which seems to be nearer the other bulb values.
Again realize this is not a proper way to do this and its highly probable that Im miles off here, i was just experimenting to see what kind of result i would get.

Regards Mattie


Posts: 564
Reply with quote  #24 

Here are two versions of the Philips booklet on their horticulture lights (USA and EU) showing different applications.  You would need more wattage of a regular white LED light, but that is offset by being much cheaper and available at a local hardware store.  I found one site selling the type of light from the lettuce video and they were more than $200 (there are many models, so don't know if these are exactly the same model).

The rope lights and Christmas lights would not produce enough light.  The newer home and horticulture lights use a small number of special high power LEDs.  When LED lighting was getting started, lights had large numbers of low power LEDs.

Kevin H

Posts: 135
Reply with quote  #25 
I have some experience using LED's for indoor growing and had EXCELLENT results with them. The lights I used were ~360W panels. I think they were 120X3W diodes with 10 or 11 different spectrums.

  The plants really liked them and clearly preferred them over HID or T5 lighting.  Similar results to the video in better quality of plant growth.  To make up for the limited coverage area I reccommend a simple light mover as a worthwhile investment. 2 panels spread out and moving back and forth can cover a MUCH greater area and still maintain sufficient intensity for high yield growing. Of course the plants on the ends will not develop as well as the ones in the middle, but overall you get a lot more coverage and yield out of each LED light/panel.  The plants in the middle experience much shorter gaps between light exposures and seemed to develop just as well as plants that sat directly under a stationary panel in subsequent (not side by side) trials.  I've read interesting studies that concluded plants experience something similar to photon saturation under intense light, but they sort of "hold a charge" for a little while and will continue to photosynthesize (process photons) even after the lights are off.  Wish I could remember more of the details. If this notion is correct then as the light moves directly over a plant it charges up the plants "short term photon storage" allowing it to continue photosynthesis even after the light has moved off.  I think the study was cited in a discussion about developing PWM type of control that would flash the lights on and off rapidly resulting in less wasted photons due to saturation. The idea was to have the lights on even less than half the time (<1/2 electric usage), but with gaps short enough the plants continue to process photons constantly. Haven't seen any fruition on that idea, but I think the diodes themselves should be capable to handle that manner of intermittent operation.

I think this is actually the exact light panels I used.  they sell on ebay for ~1,000$....

At that price would take awful long to repay the investment unless your growing extremely valuable plants.
I did not pay nearly that much for them. Lucky for me there are so many indoor growers in my area I managed to find a few on Craigslist for around 300$. I was very pleased with the results.
If you can manage the upfront investment the efficient spectrums give you a lot better plant growth per Watt with much less energy converted to "waste" heat and unusable spectra. In addition to the savings on electricity the 50,000hr rated life for the diodes does also result in a considerable savings on bulb replacements. Bulb replacements are a very significant cost to bear in mind for Fluorescent or HID lights.
I never got around to it but I before I found the CL score I was toying with the idea of building a DIY LED array.  They are really simple to set up so it might be something to consider if your willing to spend the time soldering and mounting a bunch of diodes.  I've seen some really slick homemade fixtures that were not only dimmable, but could vary which diodes were on for an adjustable spectrum output. That's fancy stuff though, all you need to do is solder a string/patch of diodes and connect it to an appropriate power supply. With a homemade panel you can also space the diodes out a bit better and eliminate the need for a mover. It's pretty easy to get the diodes in several spectra of both blue and red wavelength as well as "pure" white or whatever the most complete spectrum is called by a given brand.  Cree are a popular brand for DIY LED'ers, but there are several other well reputed brands. Be wary of extra cheap chinese diodes but no matter what test each diode BEFORE you assemble them.
I have used landscape lighting (for landscaping not plants) that ran 5m strings @24V but I think with 12V you would be much better off if you keep each string shorter lest you get too much voltage drop.

As Kevin points out the high output diodes are better for plants, I believe they make diodes up to at least 10W but the industry standard in high end horticultural LED seems to be 3W high output diodes with 10+ spectrums that focus on the red (~630-760nm) and blue (~360-480nm) with a much lesser amount of white diodes and occasionally even specific diodes for higher UV.

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Posts: 283
Reply with quote  #26 
Thanks Joe
Sorry I have not replied sooner I been fairly busy lately.
"Plants experience something similar to photon saturation under intense light, but they sort of "hold a charge" for a little while and will continue to photosynthesize (process photons) even after the lights are off."This is all useful information.The plants saturation point and charging along with a light mover is a cost saver for sure.The mechanism for movement of the fixtures would have to run on a low power requirement

"PWM type of control that would flash the lights on and off rapidly resulting in less wasted photons due to saturation" this is interesting and another approach that could be applied.

Thanks for the heads up on the Cree brand I have watched some clips on line on how to build your own lighting fixtures.It would be good to be able to see a comparison in performance between a DIY LED fixture and a one purchased specifically for horticulture .It may be a good time to post some DIY LED clips from on line as to help others who may be interested.I do have some here myself but will have to locate the links before i post them.

Regards Mattie

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Posts: 283
Reply with quote  #27 
Hello all
Here is a handy DIY led build clip for anyone interested.

Theres quite a lot of DIY build footage and articles out there to choose from.
Regards Mattie
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