Indico - They are both emitting the same kind of light. I've had both kinds of bulbs and they are both similar to work with. Generally, as you get into larger wattage cfl's, there's a point, around 75-100 watts, where the u-shaped are the only thing you can get. Conversely, under 75-100 watts you are only going to find spirals.

As with any light, a reflector will direct more light down on the plant.

PC :smokin:
PharmaCan Reviewed by PharmaCan on . U-Shaped CFLs Anyone know those long, u-shaped CFLs that usually go horizontally? Are these good for growing? Or should I look for the spiral-shaped ones? Thanks. Rating: 5