How much do you care about convenience vs. upfront costs vs. operating costs and so forth?

In (rough) order from most convenient and lowest up-front costs to most expensive but lowest operating costs:

* CFLs
* Tube fluorescents
* MH and HPS
* LEDs

Yes, they all work. It all depends on what you're looking for, what you're growing, and what's available in your area.

To start, you're growing on 5-tier rack, so either CFL or flouro tubes will fit nicely for you.

-CFL's are the cheapest to start... all you need is a standard socket and a CFL bulb. Grow with plants tops about 4-8" from bulb.
-Tube Lights (T12, T8, T5) are a bit more expensive to buy, but use less electricty (T5 better than T8 which is better than T12) so you'll save in the long run. Buy the one that you feel comfortable with and that you can easily get tubes for. T5 tubes are way too expensive in my area ($22 ea) where as T8 tubes are only $2 ea. Grow with plant tops 1-6" from tubes.

Other lights like HID (MH, CMH, HPS) need more head-room and are good for taller plants and I wouldn't use them on a multi-tiered shelf. LED's (the useful ones) are still too expensive (starting cost) to be practical, in my opinion, but are getting better and better. I'll wait a little longer before buying into them.

I personally use T8's and HPS (and sometimes switch to CMH bulb) for my orchids.

As for wheather or not you need the lights on when germinating depends on what you're growing. Some seeds like gerbera daisies need light to germinate, while most others don't.

Hope this helps.

What is this "T" thing? I'm might be newer than anybody. I just bought some plant lights from walmart and then bought a fixture to hold it in, and hung it above the plants in my greenhouse. Hmmm...one question. The bulbs that the fixture originally came with seem ok to grow with. THey are 24" long, and it says "color temperature 4200k, cri=60, 8000 hours, made by Lights of America." Does this sound ok to start seeds? Sorry so new at this...THank you.