Okay....I am still trying get the best light setup up & running before it gets cold & the trees come inside. I am now convinced that my original idea of using 1, 150 watt grow bulb (incandescent) won't produce enough lumens and won't be close enough to the tops of the trees. As the four trees I'm bringing in will be in four different places in the house, my plan was to put one light over each one. Moving on to the compact fluorescents.....I saw the following info on a lighting company's website:

These grow lights are available in 125 watt models. The 2700k bulb provides increased output in the red spectrum which promotes flowering and budding in plants. The 6400k bulb is full spectrum bulb which promotes overall plant growth. 125 watt bulbs are 9,500 lumens. Average life span is 10,000 hours. Requires mogul fixture or socket and 110/120 volt outlet. Size 14" x 4"

Here's the page from their site:

http://www.littlegreenhouse.com/accessory/lights.shtml#gardenlight

Which one would be better for citrus trees? I have a meyer w/5 nice-sized lemons on it and about 50+ bud clusters as well as a bearss lime w/2 little limes on it. I won't have enough sun for them w/just window light. Thanks! Stephanie

Go for the 6400K

I have an extra 125 Watt CF light (both 2700K and 6400K) that I haven't used, only tested to see if worked. If I can find it again in my garage, I'd be willing to sell it for half the price.

I don't need them anymore, after I threw away all of my cold sensitive bananas and never got around to use the newly ordered lights. I don't use them for citruses because all of my citruses are over wintering outside.

Hi Joe,
Thanks for the reply. I just wanted to make sure I understood your response. You have two bulbs; one 2700K and one 6400K? Or a light fixture that holds one of each? I'm looking for the ones that screw into a mogul converter. If you find them, please let me know and email me offline so we can arrange payment/shipping, etc.: sjeffery@erols.com
Thanks so much, Stephanie

What you need to know is the amount of foot candles a light puts out. Light saturation of leaves (the maximum amount of light a leaf can use in photosynthesis to produce energy) of most tree species is in the range of 1000 to 1500 foot candles, whereas full sun in most areas of North America is 10,000 foot candles or more. This means that even somewhat shaded leaves are still working at or near full efficiency. - Millet

Hi Millet,
What is the relationship between foot candles and lumens? I ended up buying a 200 Watt CFL. I understand that I should have the light as close as possible to tops of plants. I also started a new topic this A.M. about number of hours of light needed and whether a period of darkness is beneficial or irrelevant. I would be most appreciative of any info you can share. Thank you, Stephanie

A foot-candle is equal to one lumen per square foot. - Millet