Here's what I've learned. You need good dirt, full sun (close to 6 hours a day), moderate water, and well drained soil. Seriously, they need the sun. I've learned the hard way.
I forgot to do this, but its not too late. Since it stays so warm well into September in the South, I've still got plenty of time to get a couple more rounds of seeds in the ground.
One thing I've learned over the years about "gardening" with kids is to focus on one or two plants or herbs per year. There's a temptation to put tons of stuff in the ground, and then it becomes so overwhelming to maintain it all with children underfoot. Unless gardening is really your thing, it's best to go small and celebrate the little victories.
I like becoming proficient with a new flower or herb each year and slowly adding to my repertoire that way.