<span style='font-size:11pt;line-height:100%'>So far I have had fairly good results using lots of $8 - 4 foot shop light fixtures with $1 each 40 watt, cool white, fluorescent lamps. If the plants are low enough I keep them 3 inches or less from the lamps. I have two shelves where I can raise the lamps higher in order to accomodate taller plants. I have the lights on digital timers and run them for 15 hours during our nightime here in Tucson, Arizona. I run the lights at night to avoid overstressing our air conditioner which works 24/7 during our summer to keep our indoor temperatures around <span style='color:red'>85F or less during the day and down to 75F at night</span>. This basically means that the plants in the plant room, under lights see about <span style='color:red'>90F</span> during the night, which is their day, while they have an ultrasonic humidifier mist distributed by a PC muffin fan running 24/7 and the dry cooling breeze from the air conditioner swirling around them distributed by other room fans 24/7. During true day when the plant room is dark (effectively plant night) 9am -6pm, the air conditioner keeps it between <span style='color:red'>75 - 80F in summer and it goes as low as 65F during the cooler months of the year</span>. During true night when the plant room is lit by the fluorescent lamps (effectively plant day) 6pm - 9am, despite the air conditioner, which keeps most of the house cooler, the plant room, because of the lights and ballast can get up to <span style='color:red'>80 - 90F</span> during plant day. This can create even more of a day/night differential in the cooler months, because the plant room still gets just as warm as in the summer, yet gets even cooler at night.
Bottom line:
--Cool and moist air is circulated around the plants day and night 24/7/365 by use of ultrasonic humidifier, central air conditioning vent, and room circulating fans.
--6pm - 9am (plant day) Temp = <span style='color:red'>80 - 90F</span> because of all the lights and ballast running in the small room.
--9am - 6pm (plant night) Temp = <span style='color:red'>75 - 80F</span> due to air conditioning not having to work against the heat produced by the lights. In fall, winter, and spring plant night usually gets even cooler, naturally, even without air conditioning, down to <span style='color:red'>mid 60's F</span>, this is because whenever it is cooler outside than 75F, which is as warm as we ourselves feel comfortable, we open all the windows in the house, and even put fans in some to draw it in and others to force the hotter air out.
I used to use all kinds of different fancy and expensive 40 watt fluorescent plant lights. Verilux, power twists, agrolights, etc. The plants grew just as well for me under simple, cheap, discount, $1 each / or less, cool white shop lamps; as long as I use as many as I can squeeze into 18 inch wide x 48 inch long shelves - - which is usually 6. I have heard suggestions that I plan to try once I have migrated most of my collection to the greenhouse which is nearing operational status.</span>