Chard is a great autumn, winter and spring crop.
Multi coloured varieties such as ‘Rainbow Chard’ look fantastic and are as valuable as an ornamental plant as an edible one. However the white stemmed varieties such as ‘Fordhook Giant’ and ‘Silver White’ are more productive and hardier.
Swiss chard, rainbow chard, leaf beet and perpetual spinach are all varieties of Beta vulgaris subsp. cicla. This is the same species as beetroot but instead of being grown for its roots it is used for succulent, glossy leaves that are a great substitute for spinach.
Sowing seeds now (late July/early August) will give plants chance to reach a reasonable size by winter and allow for harvests through winter and spring. If the winter is hard the plants will need to be protected from the worst of the weather by a cloche, greenhouse or polytunnel.
Don’t forget beetroot and chard are the same species therefor you can eat beetroot leaves as well!