If you have an area that is not going be planted up over autumn and winter you should consider planting a Green Manure to cover the empty space!
There are many benefits of growing Green Manures - they cover bare soil which would otherwise encourage weeds and loss of soil nutrients through rain or snow over winter. They suppress weeds, protect soil from erosion and add structure.
Some Green Manures such as Legumes (beans) absorb nitrogen from the atmosphere and 'fix' it into the soil through root nodules, making it easily available for crops that follow.
They can be sown whenever the ground is to be left bare for more than 6 weeks. Most Green Manures should be dug in while the crop is fresh and green. Allow at least 2-3 weeks before re-planting to begin the breakdown of plant material into humus, which will release nutrients slowly over time.
Red Clover can be grown from spring to summer or left to grow over winter while Field Beans are of the greatest value when they are over-wintered. They can be cut once and allowed to re-grow to produce a second flush of foliage before digging in. Dig in any time up to flowering.
Phacelia Green Manure gives good foliage cover for weed suppression, for maximum effect it should be cut down before the flowers open, but they are so attractive to many beneficial insects, especially bees that it can be a good idea to leave a few plants to grow and flower to encourage these busy workers into the garden.