If you have empty veggie beds after your harvest it's a good idea to pop in a green manure.
Green Manures do what they say on the tin. They are a green crop that is not designed to eat or to admire, it is designed to protect and add nutrients to your soil. Even better the cost is a packet of seeds.
Weed and rake your empty beds then sow the seeds. The plants will grow quite quickly.
If some get killed off by frost not to worry, just leave them in the ground and they will continue to give soil protection.
About two or three weeks before you replant your crops, cut and dig in the manure. This will allow the plant material to breakdown into humus, releasing nutrients slowly over the next growing period.