LED Grow Lights

I've been an avid rosarian for many years, and am finally getting around to trying to grow miniatures indoors. I've been looking at some of the commercially available LED grow-lights, and they're insanely expensive, not to mention bulky and unattractive. It occurred to me that a lot of the info here would be highly relevant to such a DIY project. What I'm wondering is how many LEDs would be needed to produce around 2000 lumens in an approximately 1-foot square for one rose? I'd gladly listen attentively to anyone who can comment on this with some degree of authority.

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tech254 years ago
greetings all. First, the small 5mm leds don't really work for a grow light. Yes, one can grow with them but not as well as the higher powered leds. Right now, the sweet spot for flux density/ watt consumed is best at the 3 w lvl. Well, 1 watt leds are better but it is hard to get enough of them in a given area. Here be the problem, I have tomato plants that are 3f to 4f tall. I want my light to be "bright" enough at bottom of the plant as well as at the top of the plant to support robust growth. 5mm leds would work for a pancake shaped plant with all its leaves in a flat disk sort of like the shape of a dinner plate. But that isn't what I have with my hypothetical tomato plants. So, I need to start with more flux density to reach the bottom of the plant to support robust growth down there too. So, 3 w leds work good. Even better is adding little reflectors to each led to turn each one into a spotlight. Now my lights will work from the top of the plant to the bottom. Ah but using 3w leds means that I have to remove heat. I mean a 3 watt blue led that has a 500mW radient power heats up the environment the other 2.5 watts. Anyway, I am making a light for a friend. So far, I have 16 leds: 4 660 red and 4 2700 k white leds for the red end of the spectrum; 4 445 blue and 4 12000k white for the blue spectrum. That should work out for most any plant. This is the second light that I am building. The first light was just blue and red leds and didn't really work all that well. This one is full spectrum just enhanced in the red and blue light frequencies. Cost is 72.00 for the led's and drivers. I have scrounged the floodlight housing. Pulled the 100w halide ballast from it. I have to find an aluminum plate for the heatsink to mount the leds on. Find aluminum rod to make heat pillar to xfer the heat in the center of the aluminum plate to the case as there will be no fans or holes for ventilation. I plan to mount the led drivers on the outside of the case as they are already waterproof. So, as long as I don't have to buy anything else the light will cost in the neighborhood of 83 bucks. (wire and thermal heat compound) that is for 48 watt light. If lens are required then that will add about 22 bucks more. That is a one off home made light. If I were doing this light commercialy, I would order the heatsink and light pcb as one unit. That is the pcb for the leds is printed right on the aluminum heatsink. Can get higher "bulb" density that way and no wires to solder. Still, the cost is quite high. Untill the cost of the leds drops (trust me they have already dropped a lot) the lights will just cost a lot. Notice, there is no labor cost in assembling the light. Home made. Can't tell you the effectiveness of the light till we hang it over the seedlings. I can tell you that just red and blue didn't work as well as halide light did. This light is designed to replace 1 100 w metal halide grow light. 1/2 the power and 1/3 the heat.
Cavallo (author) 10 years ago
Well, for example, look at the prices on this page;


Likewise, I have some friends whose new kitchen has an optional little bank of red and blue LEDs configured as a grow light for which they paid $300.

Compared to the hobbyist projects I'm seeing here, these prices seem crazy to me. Am I mistaken?
Yes those prices are crazy but if the quality of those lights are really good then I think that should justify the price. Like these lights from http://growblu.com/shop-leds I know they are costly but the fact that they did a great job in my garden, I'm sure its worth it.
Those prices are obscene. Why not just use fluorescents?
Cavallo (author)  Tool Using Animal10 years ago
Hmm. As a matter of fact, here's someone who seems to be further along than I am with this idea;

Cavallo (author)  Tool Using Animal10 years ago
Becuase LEDs will be much simpler to manage space and heat-wise, it seems. I'm envisioning some kind of semi-enclosed, quasi-terrarium thing. Besides, LEDs would be a heck of a lot more fun. Also, any degree of success with this would probably benefit a lot of techno-forward gardening types besides myself.
Dandeman3219 years ago
I have a ton of UV Led's. Could I use just UV instead of a red and blue mix?
If you use UVB, you can boost antioxidant levels in red lettuce
no, you need both, red and blue/uv here is a good article about it http://www.sunmastergrowlamps.com/SunmLightandPlants.html
Senua6 years ago
I have been looking at buy some LED Grow lights like this: http://satandcable.com/left-categories/hydroponics/led-grow-lights

What is the best ratio of Red to Blue lights? I'm a bit confused of the options? Do I actually need any white LED lights?
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