December allotment garden

Last revised: 20 December 2017

Seasonal reminders, hints and tips.

The allotments at Jubilee Road are on clay, which is within a spade depth. Bear this in mind when selecting plants and seeds or seeking advice from growers that have different growing conditions. Gardening on clay


For a summer crop, sow a few seeds in modules or a tray. Keep warm (10°C to 15°C) until secondary leaves appear, then move to cold frame or greenhouse to overwinter for planting out in April.


Start from seed in small tray or pots of multi-compost. Water the compost, then sow seeds thinly, and sprinkle thin layer of compost or vermiculite over the seed. Keep in sunny warm place, avoiding direct sunlight. Too much warmth will hinder germination.

New shoots should appear in about 2 weeks. Move the trays or post to a cooler position, cold frame or unheated greenhouse. Bubble wrap can help keep off frosts, prolonged cold. Keep moist, but avoid over watering at this stage, as the damp can lead to botrytis and wet rot. The seedlings should be ready for planting out in March.


Thin out garlic to about 20cm apart. The planted bulbs are susceptible to fungal diseases which spread quickly in damp and humid conditions caused by over crowding. Wet weather helps spread the fungus.

Check for leek rust, which shows as bright yellow/orange spots on leaves. Yellowing and wilting leaves are signs of wet rot. To test, gently tug the plant. If it lifts easily, without resistance, it is because wet rot prevents roots growing deeper into the soil. If there are signs of white fungus on base of the bulb, dispose of the plants at council tip, not on your, or any compost heap.

Grape vines

Prune to remove all this years growth down to 2 or 3 buds. On old wood scrap off peeling bark to reduce build up of scale insects and mealy bugs.


Select one or more clumps, remove all weeds around the area and cover with very large bucket or dustbin. This should promote early growth in March for a young blanched crop. You may have to secure against stormy weather by adding a heavy weight on to top of the bin.

Over wintering plants

Many types of brassica plants like cabbage, kale, spinach and Brussel will survive into January and February if the weather is not too wet and cold.

Remove any dead leaves and fallen leaf from and around the plants. This reduces opportunity for disease and hiding places for insects, snails and slugs which will take advantage of any vegetable matter, or hide until spring to attack the next crops.

Consider netting any over wintering vegetables to discourage pigeon eating leaves, and animals digging up the loose soils.

The ground is likely to be wet, if not saturated, then drainage will be an issue. Plants will quickly rot if they remain standing in water.

A harsh frost, particularly if combined with recent rain, will damage or kill of some plants. Pick your crops regularly to take best advantage.

Root vegetables like carrot, leeks and parsnip will survive a long time if the surrounding soil is not saturated with water or frozen. Nevertheless, slugs and snails will attack the roots. Ensure and tops emerging from the soil are covered with soil to discourage frost damage and slugs. If you have a valued supply it is worth digging them up, storing in dry sand or peat in a box and in a cold dry place like your shed or garage.

Storing vegetables

Check any vegetables you may have stored for signs of damp, damage, vermin or disease.

All stored vegetables should be in dry, cold place, but they contain water and will sweat. If ventilation is poor they will rot and encourage disease. For this reason use string bags or well ventilated bags and boxes, and keep in dark cold place.

Dispose of any diseased vegetables in your food waste bin, or at council tip. Do not add to the compost bin.

Fruit trees

Check grease bands are tightly fixed around trunk and branches. Check stakes are secure. If using espalier method that wires tightly stretched, and branches firmly tied. Old tights are useful ties that provide a little movement.

Remove, use or compost any remaining fruit, as these will harbour pests.

Cut off dead and broken branches, treating large wounds with bandage or sealant. Pruning at this time of year is not advisable as this may introduce disease. While the sap is down, the tree has little resistance.

Probably too late for winter wash, but worth doing if forecast is dry and mild for a few days afterwards.

Clear weeds and competing plants from around base up to one yard or metre. Lightly fork soil and mulch area.

If planting new bare root trees, make the hole is bigger than you think necessary but ensure the tree root is not planted too deep that the grafting is below surface level. Fill with fresh soil, if available and add well rotted compost. Don’t forget to stake the new tree such that the stake is about 30° on the East side. The angle helps take the strain against the stronger westerly winds.

Any tree should be planted at least one metre from the path edge. This allows the tree to grow with little affect on the path, and you can easily control the space around the trunk. In addition the growing tree branches are less likely to affect a passer by.

Winter preparation

The difficult clay soil will benefit by adding any mulch, like leaves, manure and accumulated compost clippings. This can be either lightly forked into the surface, or spread over. There is a suggestion that a porous sheet cover over the top encourages decomposition.

If the ground is wet, stand on board to avoid compacting the ground.

Alternatively use any mulch and manure to build your compost heap ready for next year. Turn over any existing compost bin to keep it working, and dampen with water if it is dry.


Clear compost bin of well rotted material and digging it into your plot. An area where you will be growing peas or squash next next will be a good place.

Add some shredded cardboard and a bucket of water, then mix into the remaining compost, turning it over at the same time. If open, cover the heap with a sheet of cardboard or old carpet to keep in moisture and heat over winter.

Tidy up

As most of the ground will be clear, remove any rubbish and hiding places for disease, slugs and snails. These will come back in spring and hit your fresh plants.

Clean and put away any tools to reduce rust.

Check shed, greenhouse or structures for damage and arrange repairs. The weather may be kind, but timely repairs will reduce or avoid any storm damage.

Watch yourself, and others

Paths will be wet and slippery. Wear strong shoes or boots and watch where you step.