Can I use these lights for starting plants?

19 years ago

I will be starting my tomato and bell peppers from seeds at the end of the month. I did this last year and the plants did okay in a south window, but they grew very leggy before I could get them out into the garden. I was wondering if I could use lightbulbs that I have on hand from an aquarium hood. The bulbs are 65W, 10,000K compact fluorescents that I used to grow aquatic plants. They are supposed to simulate the mid-day tropical sun. I could use either 1 or 2 bulbs. Can anyone tell me if this will help the plants to grow stouter?

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Comments (5)

gawdly
19 years ago
10,000K bulbs(actinic?) are SUPER blue and AFAIK supposed to simulate mid-day sun under water. Since your land plants aren't under water, they're not much use. Look for 6500K or less.

I suppose you can experiment using them, but since I've never tried it I can't tell you what your experience will be like.

Sam
Jennifer_Peters
Original Author
19 years ago
No, these lights aren't actinic (although I do have a couple of those, too). They are very cool-looking white lights, not warm-looking at all. An experiment does sound interesting....
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maineman
19 years ago
Jennifer,

"Can anyone tell me if this will help the plants to grow stouter?"

I don't know about your bulbs, but, as others have also suggested elsewhere, I use small electric fans to provide artificial breezes for my seedlings and that helps them to grow stouter. Their leaves and stems wave in the breezes, as if they were doing exercises. Use a small gentle fan -- you don't want to grow your plants in a wind tunnel. Just watch out for your pots needing water before you expected, because the increased air circulation also increases the rate at which the pots and plants lose water into the air.

MM
yardenman
19 years ago
You can control the intensity of your bulbs by simply placing them further from the plants. Light decreases with the square of the distance. In other words, a bulb 2 feet away will provide 1/4 of the light of a bulb 1 foot away.

But you may have a problem with the spectrum of the bulbs. 10k K bulbs are very blue-shifted. As plants are (quite naturally) adapted to sunlight, I prefer to use daylight spectrum ones. You could try putting a red filter between the bulbs and the plants, but there's no telling what spectrum range you would end up with without special equipment.

It could be worth experimenting with a few seedlings, since you have the bulbs.
shrubs_n_bulbs
19 years ago
I think you could use these although I haven't tried it. The light output is almost all around 400nm-450nm, which is the useful part of the blue spectrum for plants. There is just about no red light, to mimic being several feet underwater. Maybe mix them with a warm white bulb to supply something at the red end.