As winter gets into full flow, it is unlikely you will be spending much time on the actual allotment. Preparation is the better option in this regard. Plan what seeds you will be wanting to plant in the year ahead, and get them ordered. Put together a plan of what you are looking to grow and where.
With outdoor planting a no-go for the next month or two, looking to plant some seeds indoors is the best option. Germinating seeds, either in a propagator or in a heated greenhouse, will allow you to hasten things as the year progresses.
From finishing off any leftover tasks from the end of the previous year, weather permitting, to staying indoors to plan the forthcoming year, in January there are not a whole lot of jobs you can be getting on with on the actual plot.
Continue to dig over your plot - Provided the ground is not frozen or waterlogged, complete any remaining winter digging on empty areas of your plot. This will allow the soil to break down into smaller parts and introduce air into it. If it is too wet, leave it until a few weeks time.
Spread compost or manure - Feed your soil with compost or stable manure. You can either work it in as you progress with digging over the soil, or with deep beds, spread it over the surface for it to enter the soil naturally.
Pruning of fruit trees - Take the opportunity of pruning dormant fruit trees, such as apples and pears, which will remove older wood.
Pruning of fruit bushes - Prune any fruit bushes.
Check wires and ties - Take the opportunity to check all stakes, wires and ties on your fruit trees and fruit bushes. Check to see any which are worn or broken, and replace any. You need to be checking all are secure enough for providing support, but no too tight that they will restrict new growth.
Clean pots and seed trays - What better way to spend the cold January days than cleaning up all of your pots and seed trays. Give them all a thorough wash and clean. Use a weak household bleach with a brush, which will help to prevent any diseases or viruses carrying over from the previous year to this year's new batches of seedlings.