Its OK, but really only suitable for a single plant or maybe a few low light plants. Can't see your pic, btw. I use two CFLs inside my propagator for seed starting. 2x20W bulbs cover 2.5 square feet for starting out, then I can switch up to 2x30W bulbs later on for high light plants. Most of the standard domestic CFLs are warm white, 3000K or even 2700K. These really lack any blue light and so are not good for growing longterm. Try to find something like a 6500K bulb (4100K cool white doesn't seem common for CFLs) either to replace the warm white or to use both.

I am trying to grow a variety of lettuces in an area that gets almost no natural light. The plants are in a container that is 24' x 6. I have three 32 watt 5000 K CFs with six inch reflectors hanging about an inch above the plants. Is this enough light for them? they don't seem to be growing very much. I keep the lights on for about 10 hours a day.
I've also got two sedums and a catnip - each of these is only about 3" - with one of the 32 W CF's about 2" above the plants. Do these plants need more light?

24feet?, by 6 what?

1" above the plants may cook them if your reflectors are the clamp-on circular metal ones. Supposedly, lettuce doesn't like to germinate above 75-80 degrees F.

I have a 12-18" by 12-18" area with 4 pots of lettuce, lighted with two 23W spiral CFLs, each in its own clamp-on circular parabolic/conical type of metalic reflector. To keep the lettuce cool, the reflectors are offset about 3" from the growth area, tilted at about 30-45 degrees to aim the light at the plants, with the bottom rim of the reflector about 3 inches above the plane defined by the pot tops. One CFL is a 5500K, 90 CRI from TCPI (www.tcpi.com). The other about 6000K by Feit (the daylight bulbs from Feit, in the same retail display, ranged from about 5750 to 6350K; how wierd). The lettuce seems to do fine. This set up is on a southern window shelf to supplement the winter sunlight which is shaded by trees and clouds.

There are probably several spectral distributions that could yield 5500K and 90-91 CRI; for plant growth I am impressed by the 5500K spectrum linked below; I hope that this is the one used by all "full spectrum 5500K 90-91 CRI lamps".

Here is a link that might be useful: 5500K 91CRI spectrum

I read that as 24 inches by 6 inches. If it is, then you have an awful lot of light focussed on your plants, too much for them to be happy. If you are talking about feet then you obviously have nowhere near enough light.

One 32W CFL should be able to light your one square foot area very effectively with the right relector. Maybe you would use two when the plants are larger, but more like one foot above the plants not one inch.

The one bulb for the other three plants is probably about right. Maybe raise it a little, CFLs are very intense up close, not like regular shop light fluorescents. The Sedum will appreciate high light, not sure about the catnip.

Hi everyone,

I've been thinking for a while about getting some lights for my plants in my dark student room, as well as to combat general winter glumness... I was going to post here but you've already answered my question! I was wondering if compacts would give enought light to be any use (I could alternatively get one of those 'propagation' units with striplights, but they're quite expensive). I was thinking of using two 30W daylight bulbs (good for plants and me I hope!) - see link. Just need to get some reflectors now.

I'm planning on illuminating plants in front of a west facing (but dark due to overhanging balcony) window - hopefully with the extra light they should do rather better! At the moment everything's growing very slowly or dying (in the case of a small musa and ensete which I foolishly brought).

Thanks,

Alex

Here is a link that might be useful: Daylight bulb

Here's where I get my daylight CFLs. Slightly lower CRI than your's but also cheaper. I actually got them in a sale for about four quid each! True SAD bulbs have CRI above 90 and are even more expensive, but looking at my plants all lit up in December makes me happy :)

Here is a link that might be useful: GB Bulbs daylight bulbs

I wrote:

> with the bottom rim of the reflector about 3 inches above
> the plane defined by the pot tops

oops, it is more like 6-9 inches above the pots.

My bulbs have arrived :o) I've not managed to find a proper reflector so have rigged some heath robinson thing up with a white card backing which will do for the moment. So, my question is: how far from the lights can plants be and still benefit? They are mostly shade plants (chamaedorea, ferns that sort of thing) so I'm hoping a foot or two is fine, since they need to be in the window as well.

Alex