Join Date: Sep 2003
Location: San Francisco, CA
Duration of the light cycle cannot compensate for intensity. In addition to serving no growth benefit, a longer light cycle would simply encourage algae.
You're absolutely fine running fifteen watts over a ten gallon tank. Just start with low-light plants (ferns, Anubias, and mosses) and spend the time you're earning the money for a light fixture to learn the ins and outs of keeping plants happy.
If you're new to the game, you're going to think that you're missing out on all the "fun" high-light plants, but honestly, once you're in the game long enough, you'll realize that the low-light plants are just as much fun and not nearly as much a pain in the butt.
Get the Eco-Complete, set up your CO2, and you'll be off to a perfect start. Much like a person doesn't try to bench press three hundred pounds their first day at the gym, so to should we planted tankers take it slow and learn the basics the old-fashioned way.
You'll find a lamp soon enough. You don't have to get an aquarium lamp, by the way. Any lamp with the proper spectrum will do. You might have one lying around the house in which you can put a screw-in CF bulb with a kelvin rating of 5,000 to 10,000. Or go to Home Depot and get the 28 watt Hampton Bay "Robocop" lamp for twenty-something bucks.
Look up cl's Flooded Forest here in the nano section. The dude's got all low-light plants in there and it looks phenomenal. Craig's Mini-M, too. Both have plants that are low light and, in my opinion, look better than a lot of high-light tanks I see.