The layout in the potager is based on a four year rotation. This works pretty well for me although I have not always stuck to it and had the right crops in the right place at the right time. It's a work in progress but I think I'm getting better. The idea of growing vegetables in a different area is very old and works on the principle of lessening the chance of pest or virus build-up for any particular plant in a given area. I have always done it mainly because I dont use chemical sprays and so far have not had any greebly things to deal with.
I am also trying to improve the year-round vegetable production and have started working on a seed program to remind me when the last seeds were sown. >
Below are pics of the latest seed program and vegetable rotations in descending years.