Vegetables
Potatoes for harvesting in December can be planted this month if the soil can be worked easily. In smaller gardens, concentrating on early varieties such as Cliffs Kidney, Liseta, Swift or Jersey Benne, makes sense as they are ready to harvest when shop-bought new potatoes are expensive. Most of these early varieties do not store well, so for mid-season crops it is better to choose a good keeper, such as Maris Anchor, which can be used as a new potato but matures into a useful all-purpose tuber.
Because potatoes are subtropical plants, they are susceptible to frost damage. Protect early shoots by covering them with large flower pots, pea straw or frost cloth. Sudden thawing ruptures leaf tissues and irreparable damage can result.
Other vegetables that are described as early usually mean they mature in a shorter time than main-crop varieties. Early carrots, for instance, are those which produce shorter or round roots, such as Parmex, and will be ready for eating about 75 days after sowing seed, compared with 100 days for larger types, such as Topweight.
Early white turnips, including the Japanese variety Hakurei, lettuces and radishes can be sown now in sheltered gardens that face north or northeast.
Jerusalem artichokes (Helianthus tuberosus) are a good vegetable for the beginner, as they require little attention and will produce a reasonable crop even in poor soils. Their only drawback is a tendency to become invasive, popping up from the tiniest piece of tuber left after harvesting. The plant has nothing to do with Jerusalem, as it originated in North America, and might better be called by its 17th-century name, potato of Canada. Plant tubers 30cm apart and 15cm deep in rows 1m apart. They will grow to more than 2m tall and produce attractive yellow flowers.
Globe artichokes and cardoons are closely-related perennials whose flowers resemble huge, scotch-thistle heads.
Both plants can be increased by dividing existing plants or by sowing seed.
Cardoons are grown for their celery-like stalks, while the heads (globes) of artichokes are eaten before any flower colour can be seen.
Both plants grow 1.5m to 2m tall, so place them 1m apart. If not grown as vegetables, they are fine decorative plants for the back of a garden bed.
Rhubarb roots can be planted now in rich soil. Plants (crowns) are set 1m apart, just deep enough for the bud to be level with the ground surface. Rhubarb can also be grown from seed sown in spring or autumn.
Brussels sprouts can be sown now, for planting out in the first week of December. Early planting is important in southern districts, as growth slows early and plants that have not reached 70cm to 1m in height by autumn will have poor crops over winter.
Cabbage and cauliflower plants can be planted now. Most soils will suit cabbages but cauliflowers demand rich soil and a warmer climate than their close relative, broccoli.
Onions can be sown as soon as the soil starts warming. Tip: look for fresh weed growth, a signal that soil temperatures are rising. Onions need to be in early to allow bulbs to develop to a good size before the days shorten at the end of January. Sow seeds thinly and not more than 1cm deep.
Leeks for planting out later are usually sown on a seed bed of rich soil. Adding some coarse river sand will encourage a good root system.
Shallots and garlic can still be planted in well-manured soils, spacing cloves at 15cm in rows 30cm to 40cm apart.
Fruit
If fruit trees have not yet been pruned, this should be done as soon as possible as already early-flowering trees will be showing signs of bursting into bud. Use clean, sharp pruners and cover every cut, no matter how small, with pruning paste. This may seem tedious but will reduce the likelihood of disease, particularly silverleaf fungus (Chondrostereum purpureum), which enters the tree through wounds.
