I was watching Gardeners' World on iPlayer last night and Monty planted carrots and french beans because his earlier plantings came to nothing, I can't remember what he said about when they would be harvested. I put some more carrots and beans in a couple of weeks ago and they are growing strongly, my previous plantings were a bit rubbish. I think the beans will be harvested from mid Sept onwards and I always just pick carrots as they come good.
We are only growing in containers this year as the place we are renting has no plantable garden surface (gravel, concrete and decking only).