Natural light is best for plants during all growth phases, but I'll be growing indoors, It's a good idea to have a basic understanding of the light spectrum and how it affects plant growth, in order to choose the best lighting for my indoor gardening needs.

By Photosynthesis. Chlorophyll in the plant converts carbon dioxide into food using light energy. Light quality, quantity and duration. Quantity refers to light's intensity, while duration is the length of time the light is present. Quality of light refers to its wavelength, or color according to some scientists.

Sunlight includes all colors of light. Plants only absorb light in the red and blue wavelengths, so orange, yellow, green, indigo and violet are theoretically are unnecessary.

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    I haven't done any experiments, but I would expect a typical "Daylight lamp" (ie. with a colour temperature comparable to sunlight) would be the best choice.
    – winwaed
    Commented Jan 14, 2013 at 13:55
  • Are you experimenting with only supplying specific wavelengths, and do not want to use full spectrum lamps?
    – Noel
    Commented Jan 14, 2013 at 19:47
  • I would like to use red and blue spectrum and cycle it through out the night, They say red light promotes flowering and blue for leafing.
    – N3R0
    Commented Jan 15, 2013 at 4:55
  • Commercial site, but I've always liked the "Photsynthetic Response vs Wavelength" graph, and explication on various measures of light at this site: sunmastergrowlamps.com/SunmLightandPlants.html You'll want to be sure to stimulate both photosystems I and II. Look them up on Wikipedia. If power is very expensive, you might consider going to LED lamps. Those are just starting to catch on. Commented Sep 13, 2014 at 19:16

1 Answer 1


if you want to grow chili peppers then you want lots of light. Getting a crop to grow indoors is far different than just getting a plant to grow. Your only feasible option is high intensity discharge lights.

Wikipedia describes them as

HID lamps have made indoor gardening practical, particularly for plants that require high levels of direct sunlight in their natural habitat; HID lamps, specifically metal halide and high-pressure sodium, are a common light source for indoor gardens. They are also used to reproduce tropical intensity sunlight for indoor aquaria.

Any hydroponics shop will have them in stock. They run hot and use more electricity than fluorescents so a fan may be required.

  • electricity is expensive in our country, so based on this post: HID,CFL & LED CFL are the practical way use.
    – N3R0
    Commented Jan 15, 2013 at 5:15
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    I've had luck getting cayennes, transplanted from outdoor, to continue to flower and fruit in a 2' X 4' foil lined growth chamber w a 150W high pressure sodium, and 5 23W bluish compact fluorescents. Yield was not spectacular, at least until I took the overwintered plant back outside and put it in the ground again. Commented Sep 14, 2014 at 13:48
  • Have to disagree with "use more electricity than fluorescents" statement. They use as much power as they use; 250W is the same power, going through a CFL or an HPS. Light output may be different but light intensity is usally better in HPS as it is more concentrated.
    – blarg
    Commented Oct 22, 2014 at 8:12

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