Plants love fluorescents of all type! They do not grow at all from incandescents.

Light color is measured in kelvin or K. Bluer is lower number and redder is higher. Natural Sunlight is about 5600. Incandescent are about 3000. Candle light is about 1800, very red. Most bulbs have the K written on them. Flourescents are all over the scale. Plants grow like heck on blue end of the spectrum. The low K red simulates autumn ( northern hemisphere) and this is used for flowering some plants. Sunlight is of course quite low on the K spectrum at sunrise, and sunset too.

Some people say that it is impossible to accurately measure fluorescents in K because they fluctuate. But i think the K rating is a good rule of thumb. When i start seedling vegetables in the spring i keep a standard 4ft fluorescent shop light with cool white bulbs less than an inch ( if possible) above their tiny heads. They love this and do not get the least leggy and i love that.

The mercury in the bulbs is a small amount. Life consists of trade offs, not absolutes, in my opinion, and i think using fluorescents is better for the environment in total. The most efficient flourescents are the newer T-8 bulbs which are skinnier than the T-12 tubes that we are used to. New construction is being outfitted with these and they are easy to get at home depot etc. There are new new types that are better still.

LED's are evolving rapidly and it seems like i read about new lighting breakthroughs of various nature often.

Incandescents are so very inefficient that i think making new fixtures for them will be outlawed in the not too distant future.

You can safely dispose of flourescent lights at any Home Depot in America, as well as batteries, and power tool batteries that have expired or died. they dispose of them through a Haz-MAt ceritified pickup company called 3-E. There is no charge for dropping them off.

Just, FYI.

~smiles~
Queenly