LED Grow Light Experiments


Learning about DC, or Direct Current electricity, with my LED grow light experiments for growing vegetables indoors for winter.
Here are my first 3 home made arrays, or strips of 6-high intensity 3 volt each LED’s made from cut plastic strips from old clear, see through DVD cases.

Led lights are quite linear and focused and don’t spread the light too far, so many are needed to cover adequate area. The plus side is they are very low volts and do not consume a lot of power.


A pin was used to puncture the two holes through the plastic, matching the positive and negative LED connectors rather than one large hole for the bulb. This helped keep the bulbs in place without glue.

Foil was wrapped around to help reflect more light and to help keep wiring contained and tidy. Wiring connections to LED’s were soldered and then taped to make sure raw connections are kept from touching each other. A plastic strip placed on the back before the foil, also to cover and protect wiring.

A standard computer power supply was used as a power source to convert 120 V-AC (Alternating Current) household electricity to 12 V-DC electricity.
DC or Direct Current is the type of electricity that is used in solar power. The reason Alternating Current is used for the Hydro grid is because is has to supply many households and has to pump large voltages along it’s grid in order to travel or get to everyone, and then to cover everyone’s use. When solar power is used, it is used only for the consumption to and for one household, so less current and power is needed.

computer power supply color codes

Standard computer power supply wires are color coded to show their uses. Color codes have been upgraded only slightly over the years to accommodate more gadgets, but the basics are still there. Using any two of the ground (black) and the yellow wires connect to 12 volts that is needed. Connecting a wire from green to a black ground puts power on without a computer attached. It is important that there is something there to power before putting on the power. My standard power supply had a handy on off switch, so it wasn’t constantly on, and I didn’t have to always pull the plug.

I preserved my power supply and did no wire cutting, but used the pin connectors. By lightly coating and soldering the wire ends coming from the LED’s as capping, sometimes adding more bits of wire to make it slightly thicker at the end, wires would hold in the connector pin without slipping out. As I made a couple of arrays, two array wires together fit snuggly into one pin connector, and adding more wire wasn’t then that necessary, although soldering was, to stop frays and solidify the wire. All I had to do after soldering the ends was push the wire in snuggly without any special pin connectors. I connected only to the yellow (positive+) and ground (negative-) pins needed for 12V.


My resistor set up. I used a handy wizard tool to help me calculate the resistors from

led wizard
Mr. Andersen explains circuits the best on you tube.

Mr. Andersen circuits
Here is a homemade canopy experiment made from sample led strips, and foil from 2 simple cookie sheets together. Edge rims were cut off, and new foil rims were made bent and folded over. Slightly unbent they could slide in and out of each other to any length, and then completely bent to hold the position. This set up was lightweight.

Canopy unplugged, underside. White leds in center screwed onto light piece of flat wood covered with tin foil. Strips are simply taped. I wrapped the sheet foil around a pole to curve it a bit.

Light canopy, top. Wood was then attached and screwed onto foil by two hooks. Wires are pulled through the hooks and pulled through two more hooks screwed onto the underside of shelf. The canopy is plugged into the 12v power supply.


Plants are said to like the red waves more than blue, so I will be changing these to more red.
These lights are not strong enough for the lavender seedlings below, and I will need more. So I will keep experimenting. As you can see lights can get right up close without burning the plants.
Even though there is only one red strip its waves seem to carry further than the blue, and white, reflecting or touching over everything. The red hue can be seen in most of the photos above. Right now, with white, red and blue, and including clean halogen, my kitchen glows luminously with a warm sunset type coloring.

Posted a video on you tube channel, I’ll post it here also soon.

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