Bare soil loses nutrients, so blanket your beds with fast-growing crops such as green manure
Nature abhors a vacuum and your soil speaks, in volumes at times, in weeds. Leave it bare and it will respond with a flourish of sow thistles or speedwell or a smattering of nettles; if you don’t listen, it will send out its thoughts in tendrils of bindweed and briars of brambles.
Your soil cannot lie bare over the winter months. The wind, rain and cold will damage the precious top layer; it will lose nutrients and structure, and start to erode. Thus, as your summer garden comes to the end, if you don’t provide a blanket, nature will do the job with weeds.