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What LEDS do I need to make a "Grow Light" for growing plants and vegetables indoors? 110V & 12V. Thanks! Answered

Indoor Grow Light for plants and hydroponic gardening.  I need both 110Volt and 12 Volt schematics for out off grid home.
My LED knowledge is very limited so I need the specs on the LEDS.



Best Answer 9 years ago

Surprisingly, ultraviolet is not what's most needed; what plants want is lots of visible light, without excessive heat (which is why fluorescents are better than incandescents) and without UV. Websearching on "photosynthesis wavelength":

"Actually, chlorophyll a has two peaks of best efficiency, one in the blue part of the spectrum (around 430 nm) and one in the red part of the spectrum (680 nm); however, there are "associated pigments" which take advantage of almost every part of the visible spectrum, and most of the energy absorbed is passed along a line of receptors (losing bits along the way, of course) until the energy is equivalent to that absorbed at 700 nm. Photosynthesis is *least* effective in the green-yellow part of the spectrum, around 520-550 nm."

The 680nm area is reportedly the strongest response. Which would make perfect sense; plants are green because they're strongly absorbing red.

The web also reports that photosynthesis is actually _reduced_ in the presence of UV-B light.

Sure enough, websearching for commercial LED grow lights does say they focus on those red and blue frequencies.

So: If you're looking for what's best for your plants, look at LED specs to find LEDs as efficient, and as close to those wavelengths, as you can. If you want your plants to actually look attractive, you may want to simply go with white.


9 years ago

I reccomend getting a 9 volt wall adapter and getting UV LEDs and putting a resistor on each one.


Answer 8 years ago

A year or so late, but I recommend recycling a Computer Power Supply for driving the LED lighting.


Answer 9 years ago

NOT UV plants need red and blue. visible light.

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8 years ago

i think you should use LED lights than hydrophobic.The advantages of LED Grown lights over other grow lights are that no light is wasted and therefore reflectors are not required.


9 years ago

LED's are not as efficient at turning electricity into light as florescent tube lights.

Perhaps get one of those cheap florescent fixtures from home depot and install some tubes that produce light in the "plant" range?

There is some myth out there that plants like ultraviolet light.  NOTHING likes ultraviolet light.  It is mutagenic.

You might check out http://www.squarefootgardening.com/
I've used this technique for a while.  It is very low maintenance.  But keep us posted on your off-grid project.


9 years ago

What are you trying to grow? and what are its light requirements?  Can it take some shade?  Are you trying to grow plants for produce or just start them for the next growing season?

You will probably need 2 setups (one for growing and one for fruiting) and a way of changing the distance between the lights and the plants as they grow.  Here's a site that offers DIY kits.   "Printed circuit boards may be purchased for $5 each plus shipping."

It's notoriously difficult to grow vegetables and get at least some production indoors.  I can't think of a gardener who even tries to grow vegetables indoors.  People usually use greenhouses/cold frames or just start seeds for the upcoming growing season.  I'm overwintering some plants and trees in my garage, but they're pretty much in hibernation right now.  I've also started seed indoors.  And then there's the issue of gendered plant flowers (e.g., squash) or gendered plants (e.g., blueberries) and lots of other considerations (e.g., soil temperature for germination and variations in night and day temperatures).

Answer 9 years ago

I have tried vegetables.. and failed spectacularly.  Likewise on a porch with too much shade.


Answer 9 years ago

Hydroponics foilks have been growing stuff indoors for years. Until recently the only light sources we could use were metal halide or sodium lamps, but the modern fixed spectrum LEDS offer a whole new realm of energy efficiency. Plants could have been engineered for LED lighting......

I'm hoping to get a system going at work over the winter here.