Hydroponics 101.4: Light Requirements

Hydroponics-101

I’ve been growing plants using hydroponics for a few years now, both at home and in the classroom. For the first several years of doing hydroponics and aquaponics systems, I used a bank of T-5 fluorescent bulbs and they worked okay. But in this last planting, which I have set up in my basement, I purchased a bank of LED lights. I am passionately green and I read that LEDs are much more energy efficient and last much longer than any other type of bulb. I also read that LEDs can be tailored to provide the exact wavelengths of light for plants and flowers. You see, plants love light from the blue and red ends of the spectrum. While fluorescents provide some of that light, much of a fluorescent’s light is white and that is a waste of energy because plants use very little white light.


We’re currently in a series exploring Hydroponics {read our previous entries 101.1, 101.2, 101.3}.


The bank of LEDs was about $275 dollars. This was comparable to the cost of a T-5 bank of fluorescent bulbs, but I was astounded at the small size of the LED bank!

T5-and-LED-Light

I was blown away by the light though! What the LED bank lacked in size, it more than made up for in intensity. The instructions stated that the light should be hung at least 24 inches above the plants. I was able to hang it at about 22 inches. I was stunned that the light covered an area of about 2×4 feet where the plants were located. This from a bank of lights that is five inches wide and 18 inches long! My fluorescent bank was 22 inches wide and 46 inches long.

I left the light on while I worked in the basement. After about 15 minutes I started to see everything in a green aura. The intensity and wavelength of the light was affecting my vision. I decided to turn off the light and construct an enclosure around my plants that had Mylar reflective material on the sides to reflect the light back on to the plants.

HydroponicsLED

My plants are now bathed in blue and red light and are growing wonderfully.

Oh, and my vision is back to normal.

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