December to-do list

Plastics and synthetic fabrics – particularly if they are recycled or extra long lasting – get the nod of approval even from the organic camp. Amongst their many attributes, they are just wonderful at keeping out the cold.
As temperatures drop below zero fleece comes into its own to protect tender crops. Bubble wrap (often thrown out by big shops and free to anyone not too proud to pick it up) comes in handy for lagging your pipes and for 'double glazing' the greenhouse or cold frames. Pots in the cold greenhouse will be kept a few degrees warmer if you stand them on a sheet of polystyrene and you can protect your winter salads from frostbite by growing them in polystyrene boxes (thrown out by fishmongers) with a sheet of glass or clear plastic on top. Another way to prevent cold frames from becoming too cold for comfort is to put one on top of the other.
If you are feeling energetic an excellent task to get done and dusted is the annual greenhouse or cold frame scrub. Pests and diseases as well as moss and algae are given to lurking in cracks and crevices. Scrape them off with a bendable, non-scratchy tool like a plant label. Wash the glass down with soapy water to which disinfectant has been added. There are now powerful organic disinfectants on the market made from citric extracts that are harmless to plants.
Cleaning the glass will let in extra light which will be appreciated by your plants in winter when light levels are low. Scrub down the staging along with flower pots and seed trays taking care to clean under the rims. Remove any weeds that may have appeared and sweep the floor. Discard any ailing plants as they may infect others. Slow down on watering through winter as plants slow down to tickover.
Finally, before awarding yourself with a halo, clean your tools. Clean, sharp tools will last longer and will serve you better. Wash them, dry them with an old rag, rub off any rust with wire wool and oil them ready for winter. Sharpen them if necessary and hang them up to keep them dry. Incidentally, best practice, as taught in horticultural schools, is to clean your tools after each job to prevent the transfer of pests and disease from plant to plant. Then at the end of the day the metal parts are dipped into an oily sand mix so that they stay sharply honed and rust free.
Check and repair fences. Avoid using wood preservatives as they are toxic. Wood rots fast when in contact with the soil so, if you are making a new fence or wooden structure, it is best to give the posts a concrete footing or metal 'shoes'. Source second hand wood from here. If you have natural hazel and willow structures and plant supports you can extend their lives by rubbing on linseed oil to prevent them drying out and splitting.
December is the ideal time to prune apples and pears, gooseberries and currants. Autumn raspberries can be pruned right back to ground level between now and February. Leave the stone fruits, peaches and plums, until summer to protect them from silver leaf disease.
Cut out the dead, diseased, damaged as well as crossing or rubbing branches of apples, pears and gooseberries. Aim for an open goblet shape that lets the wind blow away unwelcome airborne spores. Currants can be cut back hard. Once established, taking out as much as half will only serve to reinvigorate them. Remove the dark old wood right down to base, leaving the lighter new wood and cut off anything that is in the wrong place. Grape vines are a little more complicated but need to be pruned before Christmas. If left until later they will 'bleed'. A golden rule when pruning is to use sharp tools that are up to the job.
Protect any vegetables still in the ground from bitter winds and icy weather. Earth up spring greens to prevent wind rock. Do the same for Brussels sprouts and continue to pick from the bottom, removing yellowing leaves that could harbour disease. Put straw or bracken around (not over) the crowns of globe artichokes and rhubarb. If you still have root crops in the ground, cover them with a thick layer of straw, bracken or leaves. Alternatively put cloches over them. Spread a good thick layer of manure round fruit trees. Carry on clearing leaves. Use two planks to collect them to avoid the possibility of picking up dormant creatures. Don't let up on feeding the birds. Keep inspecting your stores and remove anything that is less than sound.
Once the plot is all wrapped up and ready for winter, I hope you will feel fully justified in curling up by the fire and enjoying the fruits of your labours as the year draws to a close.