I'm new to starting TAM Mild Jalapeno peppers from seed; this is my first time ever starting any peppers from seed.
I was lent a full-spectrum fluorescent light yesterday, and I now have it turned on and suspended about 7 inches above the tops of my plants (they do not have their "second" leaves yet).

There are two bulbs in one "holder", and they are both GE F40PL/AQ bulbs.

Is this going to work? Should I buy a different color-temperature bulb? Do I need to suspend it higher/lower? What ratio of light/dark should I try for?

1 Answer 1


3100k is a rather low color temperature for full spectrum (which is usually considered about 5000-7000k). Nevertheless, pepper plants will still grow with lower color temperatures, although they probably won't reach toward the light as much. A much stronger bulb wouldn't hurt either.

Anyway, your peppers should grow fine for most people's gardening purposes, although the setup may not be ideal for growth (which may be a problem if you're just getting started). I don't know exactly how fast they'll grow in that light, but they will grow. However, they should grow a whole lot faster if you put the light closer than seven inches. As close as possible without burning the plants is normally ideal. (One or two inches is great.)

Edit: Your bulb seems to have a spike in the blue end of the spectrum that may not be typical of regular 3100k fluorescent bulbs. This may mean that your light is pretty good overall for plants. Granted, the wavelength of the spike could be somewhat higher, but it's still in the useful range.

I might add here that lower color temperatures are more red and higher ones are more blue. Blue is great for leaf growth. Red is great for flowering. I've found that my lower color temperature bulbs seem to ward off damping off better than high color temperature bulbs, too. Your bulb follows this rule, except for a few spikes here and there, which seem to make this a better bulb.

  • I thought that 3100K was a bit low, too...but it says, "full spectrum". (Though I did read that "full spectrum" is a marketing term, so I guess that explains that.)
    – BenjiWiebe
    Apr 24, 2015 at 22:50
  • Would it work to replace just one of the bulbs with a 6000K replacement? Would it be worth the cost?
    – BenjiWiebe
    Apr 24, 2015 at 23:05
  • @BenjiWiebe How much do the bulbs cost? Don't forget that how close your plants are to the bulbs will probably influence the growth more than the color temperature. If you can't lower the lights, you can raise the plants. Apr 25, 2015 at 20:47
  • @BenjiWiebe Actually, look at the spikes on the blue end of the wavelength in the graph they have. One of those spikes corresponds fairly well to a wavelength that plants like for growth. Maybe this is a special 3100k bulb. It should be fine for your plants. I would try it personally, but if you want to get a 6000k bulb to go along with it, that would be great, too. Apr 25, 2015 at 20:51
  • 1
    I wondered about those blue spikes on the graph, too. I guess I'll try using it. As to lowering the bulb, I did. It is now a tad less than 2 inches away from the tallest seedlings.
    – BenjiWiebe
    Apr 26, 2015 at 3:26

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