Plants to plant in planters on a deck?

I found this excellent plan for building planter like boxes on a deck rail. My deck is 30 x 12 and has railings on it. I found plans to build and place these planter-like boxes on top of the rails. What they are if you can picture this in your mind a moment is 4 pieces of wood that look like bottomless planter boxes, the rail of the deck itself becomes the bottom of the planter box with dividers in it. You place flowers in pots and then place them in the planter like boxes which are secured to the top of the deck rails. You wind up with flowers along the railings of the deck. A neighbor of mine is going to build some for me to go all round the deck and then will then fasten them on top of the deck rails, I have lots of pots to plant flowers in and then will place them all around the deck rail and the pots will be secure that way on top of the railing. Now here is my question: What type of flowers should I plant that will take direct sunlight and rebloom year after year in the pots? I live in NW Florida and the flowers would get direct sunlight, I'm in zone 8.

Those are great ideas for deck planters. I'm in zone 8b and we have really high temps right now. But in your area you could plant trailing portulaca which comes in many different colors. They look sort of like little tiny roses. Purslane is another trailing plant that can take direct sunlight. Vinca, mini zinnias, and verbena are all good ones for direct sun. And they all come in several pretty colors. The plants I named are pretty much no fail plants and don't need a lot of water or special care. In your zone they may even reseed and come back in your boxes next spring. Good luck! Lin