Last year I grew a couple of sweet pepper plants on the roof. This year I plan to do better, bringing bok choy, snow peas, scallions, green beans and a few other goodies into the mix. It's still a bit early to put any plants outside, but I'm already starting to prepare my workspace and by mid-March some of the cold weather crops including snow peas and spinach should be ready to plant.
This weekend we picked up a 6' x 8' outdoor rug to throw on the roof and provide a little layer of protection between the planters and the rooftop. We also picked up a few largish planters and a good 160 pounds of cheap potting soil without any chemical fertilizers or pesticides. Believe it or not, the 160 pounds of material wasn't enough to fill the four planters you're looking at. I think I'll need another two or three 40 pound bags, and I'm planning to get a few more planters for additional plants.
It'd be nice if we had a back yard with actual dirt, but unfortunately we have just a few square feet of concrete behind the house and not much sunlight, so the best option available to us is to lug heavy bags of soil up to the rooftop. But hey, part of the fun of gardening is the exercise, right?
Anyway, I already snagged some organic snow pea seeds as well as seeds for garlic chives and scallions/bunching onions. I'll probably start the chives and onions indoors in a few weeks and set them outside in April. The snow peas should be good to plant in the ground in mid-March, and later this month I'll lay down some spinach as well before adding bok choy in April.
Right now I'm thinking the large circular planters should be good fro the snow peas and I'll add the scallions and onions around the base. When it starts to get hot out, I'll pull the snow peas and replace them with green beans. The wider planters are for the spinach and bok choy.
Now I'm making myself hungry.