I picked up a copy of a little book called The Wartime Weekend Gardener a few years ago in a charity shop. Published in 1942, it's a wonderful snapshot of how the Dig For Victory campaign encouraged people who had never got their hands dirty before to raise their own food.
It takes a novice gardener with very little time through every task, weekend by weekend, they will need to perform to grow vegetables, and some fruit, for themselves. It also has chapters on raising hens and rabbits for food. Even today it stands as a clear and concise guide to work by.
Anyway - tasks suggested for the first weekend of January:
Plant Jerusalem Artichokes
Sow hardy salads and a few carrots to grow under glass.
Lift Rhubarb roots and replant for forcing in the dark.
Finalise seed orders.
I guess even then the trick was to keep on top of things until all hell broke loose in March.