I agree. Florescent lights are the best value considering purchase price and efficiency. And "shop lights" (long, striaght tubes) are the cheapest form of fluorescent.
For efficiency (more light for less electricity), T-5 fluorescent tubes are usually a little more efficient than T-8s, and MUCH more efficient than T-12 tubes. But T-5s are still rather expensive to buy, so T-8s may be the "sweet spot" for buydget -vs.-light intensity.
LED lights are claimed to be much more efficient than any fluorescent to RUN. But they are much MORE expensive to buy. Wait a few years before investing in LED lights for plants. Some of the cheap LEDs now sold are said to have poorly balanced resistor networks, which makes some LED elements burn out very early.
But what is CONVENIENT for book-case shelves? Maybe clamping a "CFL" fixture onto each shelf, aimed at the shelf below it? "CFL" or "compact fluorescent light" bulbs have a thin white glass tube wrapped up like a twisty pretzel into a light-bulb-shape. I'm pretty sure they are less efficient than a shop light. But they may be convenient for your setup.
If you go with CFL bulbs, you'll need cheap clamp-on fixtures, so check out Goodwill or Salvation Army or especially Habitat For Humanity "Restores". Buy the most powerful bulbs you can afford (the most lumens).
If you Google "clamp-on cfl grow light", you will see many, but those are priced for the indoor "recreational drug" grower. Expensive. For example:
http://www.littlegreenhouse.co...
Lots of lumens, but LOTS of dollars!
If you can find the same gadgets at Harbor Freight, intended for backyard mechanics, they may be cheaper. I can't browse most of those "indoor hydroponics" sites from work!
Target calls it a "clip lamp" and is cheaper than some.
Room Essentials Clip Lamp - Black (Includes CFL Bulb)
Room Essentials ... $12.99 - Target
Wal-Mart has a NICE clamp with big reflector for only $6.28, bulb not included ... but it seems designed for incandescent bulbs. I would think that a modern CFL bulb, with its own built-in ballast, would also work.
http://www.walmart.com/ip/Bayc...
P.S. Ignore hype about "grow bulbs". A cool blue bulb is fine for most applications not involving flowering. For the same price as a "white" bulb, you'll get a "grow light" only 1/3rd as bright. You would need three of them to equal the brightness of one white bulb. If something about weird-colored bulbs with high prices appeals to you, consider: plants mostly just need lots of photons. Indoors, it is always too dim for them. When they don't get enough brightness (photons, or lumens), they are just plain unhappy. The idea of "a little more blue" or "boosted reds" is more suited to washing white and colored fabrics than to growing plants. They just want bright, reasonably balanced, light!
If you are tempted to spend three times as much for a pink-purple "grow light", instead just buy a "white" bulb with three times as many lumens. Or two fixtures with white bulbs. The plant will be 2-3 times as happy, or you can position the bulbs twice as far away and still keep the plant happy.
I never turned this blog entry into an article because I couldn't find reliable spectra to prove the point. If you click on it, you'll have to page down or go to the "second page" to find the entry on fluorescent tubes.
Also, I see that all the "carriage returns" have disappeared, so it's hard to read.
http://garden.org/blogs/view/R...
"But don't spend money on "spectrum" at the expense of brightness. Brightness (intensity) is more important, and it comes from lumens, plus closeness to the plants, plus good, clean reflectors. I plan to continue using one cool blue and one warm red tube to cover both ends of the spectrum at least cost, greatest efficiency, and better bulb lifetime.
Broad spectrum "grow-tubes" (
tri-phosphor coatings) are a little different from color.
Broad spectrum tubes have tri-phosphor coatings to "spread out" narrow spectral peaks. They have a more uniform distribution of intensity all across the spectrum, instead of sharp peaks and low valleys.
I've read that really expensive grow-tubes are just moderately expensive "broad spectrum" tubes that were re-labeled with marketing claims.
Both broad spectrum and grow-tubes are less efficient, more expensive, and don't last as long as regular tubes. It's debatable whether broad spectrum tubes do any better for seedlings
at all.
I believe that chlorophyll absorbs it all and turns it all into energy (except for the narrow green band that makes plants look green). But there may be seedling subtleties that I'm unaware of.
http://en.wikipedia.org/wiki/F...
See "Phosphor composition" .
