If your talking about cfl bulbs for a 4 foot tank they can work. But I would use 3 of them spread nicely to get good coverage.
You going to want 6500-6700k bulbs. Best for plant growth. Start with 13 watt cfl in that range and go up to the bigger ones once the tank is establish. The beginning stages are always tough, plants are trying to establish, you dont have a good level of healthy bacteria growth, and generally too much light for such a low plant mass. I rarely see someone new to planted tank come out guns blazing with a fully loaded planted tank.
If you can afford to plant heavy then do it right from the start. Stick with faster growing easy plants and gradually replace with harder more challenging plant. Starting with anubias and ferns and mosses are always suggested but I completely disagree with it. A newer hobbyist goes out and buys a few of each and then weeks later looses it all to algae. Reason is they can only afford or only willing to get a few and see how things go. But this causes a bad situation that is likely to fail even from an experience greenie. The plants are just too slow at growing to outcompete algae.
This isn't to say that you can't incorporate these in your scape but keep in mind the majority of your plants at the beginning should be fast growing stem plants.
Either that or start with floating plants and slowly reduce the number of floaters as time progresses. Floaters are a great way to block excess light, acting like a dimmer switch.
