If you want to supply chives, thyme and sage over the winter months you need to have plants indoors, more than you’d need over the summer as growth is slower and leaf quality lower. Grow them in pots or in the ground in a polytunnel, greenhouse or similar – in addition to those you have planted outside.
I grow many different annual herbs all year round too, such as coriander, chervil and dill – I do this by sowing (on heat in autumn/winter/early spring) every 2 weeks into module trays. These are either planted into a polytunnel and grown on in pots.
In the summer months these herbs bolt, so a regular sowing is still crucial to ensure a supply,
Good luck!
Steph