Cold January does not make you want to come to the plot! However, although there is not much to do growing-wise, there are still crops to harvest, kale, leeks, and hardy cabbages hiding under the frost and snow.
Visit your plot at least once a week to check on it especially after high winds if you have a shed or poly tunnel! January is a good time to settle down with a cup of coffee in front of the fire with a seed catalogue to start planning your sowing year. It’s also a good time to sort through your old seed packets to check use-by dates. Some seeds will lose their viability and don’t last well, e.g. parsnip seeds are best used fresh each year.