regarding lights and their spectrum, wattage/etc, and wintering plants and how and why they bloom:
the sun throws of a fairly consistent amount and wavelength of energy on a universal level, however, of course the relative positioning of the planet, how it is on its axis, and positioning in its orbit as well as the various pulls of other bodies masses in our system effect those waves/particles of energy and how we in whatever location we are on earth receive them.
The spectrum of visible light to the human eye is roughly 390-700nm or 470-790 Thz . Bees can see much lower, as low as 300nm, in the ultra violet....they call it ultra violet, because what we have defined as the color 'violet' is about 380-450nm, and 300 is lower then that even.
due to planet orbit, rotation effects of other bodies masses, as well as our own local environment even, the spectrum of light shifts during the year as well as it's strengths. This has a effect on triggering the internal processes of the plants...ie fruiting, flowering, growing. and yes, that is a simple way of putting it, obviously a lot goes into it, including local environment, nutrition, the plants itself, etc. the various wavelengths sizes passthrough, vibrate and effect different nutrients and aspects of the plant as well as the environments around the plant which trigger these phases.
wattage is a measure of energy, not a measure of how bright a light is, it is a measurement of how much energy is gave off, but not the spectrum of energy that is gave off or the amplitude of specific wavelength strengths gave off. most florescent grow lights are very weak. there are high intensity high energy lights for growing, but they also have to give out the right spectrum of light. LEDS are now being produced to give off light in the right spectrum's, as a rule so far, LEDS generally have more narrow spectrum's of light than other types, but they are way more efficient/less costly and a lot cooler when ran. once someone understand the actual light requirements though, as well as the nutritional triggers of a plant, they can grow it indoors as easily as out, and even plants which are typically not in their grow cycles, ie annual, bi annual, etc can be tricked into renewing and staying alive /fruiting much more. tomatoes are extremely easy to do this with, not to mention using one plant as the mother plant and remaking genetic copies by using cuttings/etc with.
hope this helps somewhat. here is a good article on the effects of lighting if you want to understand more of the specifics:http://www.slideshare.net/Timjoelangley/the-effects-of-light-on-plants