Allotment & Vegetable Gardening in December

Harvest

Usually December means hard frosts and it's time to harvest winter cabbages and cauliflowers. Sticking with the brassicas, the Brussels sprouts should be starting. You are allowed to eat them on other days as well as Christmas day!

Leeks should be about ready, just take what you need and leave the rest to stand until required. Leeks are much better harvested from the garden as they are required but in severe weather this can be difficult, so you can lift a few and heel them in on well dug ground, this will not freeze solid.

The carrots should come up for storage now if they haven't already, store either in peat or sand or even a traditional clamp.

Lift celery, parsnips and swedes although parsnips and swedes are very hardy and may be left if the ground is not needed. You can always cover them with fleece or straw to help stop the ground freezing them in.

Jerusalem artichokes will be available and you can start on Salsify and Scorzonera. Salsify is often called the 'vegetable oyster' and properly cooked is a wonderful vegetable.

It's worth checking any vegetables you have in store and removing anything that has started to rot before it spreads. Potatoes especially need to be checked and watch out for slugs that have emerged from a potato to go and damage another one.

Other crops you may have for harvest:

Perpetual spinach, celeriac, chicory (non-forcing and forcing varieties), endive, kale, kohl rabi, lettuce, winter radish, spinach, turnips.

General Jobs in the Garden

Digging can continue, when weather allows. Particularly with clay soils, digging when the soil is wet and sticky can do more harm than good. It's also more hard work.

As with October & November, as ground becomes vacant, you can dig it over and spread manure over the surface. Leave the soil roughly dug in large clumps and the worms will break these up as they get the manure. The freezing and thawing of water in the soil will cause the soil to break up finely so becoming easier to handle in the spring.

Winter is a good time to undertake double digging, incorporating manure into the bottom of the trench and deepening your topsoil.

Stake any young trees and tall brassicas to prevent wind rock damaging them by loosening the soil around their roots.

Ensure compost bins are covered to prevent excess rain leaching the nutrients and to keep some of the heat of decomposition in.

Soil analyses. Autumn is a good time to check soil pH (potential hydrogen). This is measured on a scale of 1 to 14 with 7 being regarded as neutral, although in gardening terms 6.5 will support most plants. Below 7 is acid and above alkaline. If you want the best out of your garden send soil samples away for professional analysis for both pH and nutrient content or utilise a kit or meter readily available from garden centres and DIY stores.

Try and keep things tidy to avoid providing winter homes for pests waiting for the spring.

Take hardwood cuttings of soft fruit. Gooseberries, red, white and black currants, worcesterberries, jostaberries and vines can all be propagated by cuttings inserted in the open ground now. Choose sturdy well ripened shoots of this year's growth cutting them just below a bud and trimming to just above a bud. For black currants take them about 8-10 inches (200-250 mm) long, 12-15 inches (300-380 mm) for the other fruits. Insert them into the soil to about half their length. It is customary to grow all except blackcurrants on a short stem - so remove the buds from the lower part of the cutting. All the buds should be left on blackcurrant cuttings.

Leaf fall should be well underway and to recap on October & November's advice:The leaves will start to fall very shortly and these are a valuable resource. Prepare for them by building a leaf mould cage. Very simple to do, you just drive four stakes into the ground and staple chicken netting around to make the cage. Pile in the leaves and leave them alone for a year. You will find the pile reduces by two thirds at least, so keep filling the bin as more leaves fall. If you have one those marvellous garden vacuum mulchers that suck up leaves and chop them, you will find the leaves rot down much more quickly. Watch out for council sweepers, they may just drop you a load of leaves when they call to collect a few veggies off you.

Sowing, Planting and Cultivating

You can still plant your garlic cloves now. They actually benefit from a period of cold, which prompts growth later. They don't like to sit in water, so if your soil is heavy and holds water, try dibbing a hole with an old spade handle or suchlike. Put about an inch of sand into the base and plant the clove on top, filling above with fine compost. This ensures good drainage and stops rotting.

Remember the pigeons will be on the look out for food, so net your brassicas to keep them away. It's worth removing any yellow leaves from your winter brassicas. They are doing no good and encourage diseases such as botrytis.

Onions sown just after Christmas will make excellent plants and bulbs, benefiting from the longer growing period. Sow them in seed boxes in the greenhouse, or you can use cold frames if they can be kept frost free. Remember that cold frames can heat upto unacceptable levels in a little winter sun so particular attention must be given to ventilation.

Fruit

You can plant bare rooted fruit trees and bushes in December and prune apple and pear trees. Cut down canes of autumn-fruiting raspberries which have

finished fruiting and burn to prevent fungal diseases spreading.

Check any young trees are well supported with stakes and ties. Stakes can tend to work loose, which means they won't be doing their job of preventing wind rock loosening the roots.

In the greenhouse

Successional sowings of winter salads can continue. Ventilate on warmer days to prevent moulds getting established.

Seed Order

December is the traditional month to go through the seed catalogues, decide what you want to grow and make a list. Then realise you'll need 10 times the room to plant everything you want to grow!

Do try the lists on this site - Vegetable Seeds - they're broken down into types (cabbage, carrot etc) but list seeds from various manufacturers to make it easy for you to compare.

There is also a list of UK seed suppliers on the site. Thompson & Morgan also supply Canada, the USA and most of the world.

Monthly Vegetable Growing Articles

• What to do in the Garden in January
• What to do in the Garden in February
• What to do in the Garden in March
• What to do in the Garden in April
• What to do in the Garden in May
• What to do in the Garden in June
• What to do in the Garden in July
• What to do in the Garden in August
• What to do in the Garden in September
• What to do in the Garden in October
• What to do in the Garden in November
• What to do in the Garden in December

There is no such thing as an absolute set date for a job in gardening, for a start temperatures vary according to where you are in the country.

Winter comes earlier to Scotland than Devon. Next, each year is different; some warmer and some colder although the trend is toward warmer the exception proves the rule.

So, adjust for where you are and the weather

Allotment Articles
Help & Advice