300W LED Grow Light

Thread Starter

Dan K

Joined Jul 30, 2010
I decided I want to test out LED technology in the growing environment. I hear very good things. Problem is the pre-built grow lights on the market are very expensive, not worth it. I figure I can cut the cost down a TON if I just make my own. The only requirements are that it is safe and reliable. I am dedicated and willing to learn.

Right now I plan on using 100 Red & Blue spectrum LEDs that are 3w each. What is the best way to wire all this up? I have no knowledge of LEDs besides the very basics. I have been looking for a place to start picking up info specifically for my project but I have not been finding good results. I am strictly confused on how to wire everything/what components I need. I have no problems constructing a proper housing with a fan or whatever to cool it a bit. I just need some help getting started so I can understand whats going on, anyone have any useful links relevant to this project?

How hard of a project is this from someone who is a noob? 1-10 rating? If anyone has any how-to information or diagrams that'd be helpful.


Joined Oct 15, 2009

Let's see a 150W high pressure sodium fixture/bulb = $100.00 (times 2 for 300W=$200.00)
Now 100 x 3W LED's at $5.00 each if you get a great deal = $500.
But assuming you have calculated needing 300W of typical lighting does not equal 100x3W LED's. Typically 15-20W of LED's equals 100W of HID lighting.
So for 300W of HID you need 60W of LED (20x3Wx$5.00=$100)plus constant current drivers plus heatsinks... I bet you could get away with $250 for a 60W LED grow fixture that would be comparable to a 300W HPS bulb.
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Joined Mar 24, 2008
A lot of folks also try to use grow lights using conventional LEDs. I have no clue how well it works, but I've drawn quite a few diagrams for folks.
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Joined Apr 5, 2008

From the wiki:

LED lights have also recently become very popular in gardening and agriculture. First used by NASA to grow plants in space, LEDs are now used in home and commercial applications for indoor horticulture (aka grow lights).[17] The wavelengths of light emitted from LED lamps have been specifically tailored to meet the exact peaks for chlorophyll absorption in plants. By leaving out the light that plants don't use, LED lights trigger the proper photosynthetic responses of the plant, allowing the plant to grow more efficiently and effectively. The Red and Blue wavelengths of the visible light spectrum are used for photosynthesis, so these are the colors almost always used in LED grow light panels.[17] These lights are attractive to indoor growers since they do not consume as much power, do not require ballasts, and produce a fraction of the heat of HID lamps.[18] Since there is a significant reduction in heat, time can be extended between watering cycles because the plants transpire less under LED grow lights. Due to this change in growth conditions, a cautionary warning to those using LEDs is to not over-water the plants.[17]
This is the full page:



Joined Sep 26, 2009
And will reduce the thermal signature in the police helicopter I.R. cameras...

What am I saying - I'm sure you're not going to grow that kind of plant!

Actually, those are the "plants" they are growing with these types of light, I mean, who's going to go through this much trouble just to grow spices;)..

Here in MI. There has been a boom in the Medical sale of it and there are a lot of people who are signed up as "providers" that have grow houses all over the place.... I have been approached by a couple of people interested in having me design something for them along these lines......

B. Morse


Joined Apr 20, 2004
If you please, the OP has a request for a small grow lamp. Commercial growers of illegal plants get caught because their houses glow like a Bessemer converter in IR, and their electric bills are the size of the Pentagon's. 300 watts is just more than a good reading lamp.


Joined Sep 7, 2009
I'd love to grow chilli plants all year and I think it would look good in the corner of the room.
I'm not sure how important the wavelength of the light is. If I read right it should be 465 and 665 nm. High power blues are available in 465 but most of the reds seem to be 630 nm.


Joined May 9, 2009
$100 :eek: you'd be better off building one of your own.

It really is quite simple. Some resistors and a power supply will be more than enough. For example you could get a 3V 5A supply and try that, wiring all the LEDs in parallel. (You may need a resistor for the reds.) Or you could wire the LEDs in series with say a +24V supply. I could draw up a schematic if you want. But you need to tell us what exactly you want.