One problem is that the CFL’s don’t have reflectors like the shop lights do. I put aluminum foil above the lights to reflect light back down. White paper covers the back wall and the sides of the shelf to reflect more light. There is also a piece of white cardboard that clips on the front. Besides reflecting light back in towards the plants, the front and side panels help keep the plants a bit warmer as well as keeping curious cats away from the plants.
Based on energy cost calculations I think my new light system paid for itself in the first year. Part of that was reduced energy consumption along with the CFL rebates and being able to turn off half the lights for part of the 2 ½ - 3 months of the year the lights are used.
I was concerned about not having the proper mix of light wave lengths with the CFL bulbs. I used two cool light bulbs along with the regular ones. The cool light bulbs have a bit of a blue tint compared to the regular ones. Plants need blue and red light. Green light is reflected off the plants (that’s why they look green) and is of no benefit.
I have been augmenting part of the area with LEDs based on some LED experimention I have been doing. I added some LED lighting with red and blue LEDs. These are used with the CFL lights. If I turn off the CFL lights the plants have a strange purple coloration. I think that the LEDs helped. The tomato plants seemed less leggy than in the past. I need to build on to the system, but it probably won't happen this season.
New LED bulbs are available for reasonable prices. As the CFL bulbs get dim or burn out I have been replacing them with LED bulbs. I doubt I will have to replace them again.
Overall, I am very pleased with this set up. The plants are doing better than the old system and it is saving money on the electricity bill.