December in the garden

Sowing & growing

• Sort out any leftover or half-empty seed packets and throw out any that are now out of date or damaged.
• Saved seeds left to dry can now be cleaned and packed and labelled. Take the time to organise them into seed tins.

Bulbs & tubers

• Check summer-flowering bulbs and tubers that are being stored over winter. If any show signs of mould or rot, remove the affected one or separate to prevent it spreading.
• Bring forced bulbs into a warm room to encourage them to flower.
  If you still haven't planted your tulip bulbs, there is still time in December and even January, provided the ground isn't frozen.

Harvesting

Lovely things to pick and arrange from your garden in November:

• Seed heads, berries and hips: make a wreath using anything you can forage from the garden eg spindle, rosehips, Chinese lanterns, agapanthus and hydrangeas
• Bulbs: the first of your indoor bulbs (eg Paperwhite narcissi, hyacinths and amaryllis) start to flower
• Tender perennials: chrysanthemums and alstroemerias from under cover.

Pruning & tidying

• If we have a ‘White Christmas’ remember to shake snow off trees and shrubs after enjoying the sight of them. The weight of snow can damage branches and stems. Don’t worry about snow on low plants, it actually protects them against hard frosts, acting as a blanket over them.
• Check newly planted trees and shrubs to see if they have been loosened by winds or lifted by frost. If this happens, gaps form around the roots causing them to dry out. If you see a crack around the plant, firm in again gently with your feet.
• Prune climbing roses now; cut away diseased or damaged growth and tie in any new shoots to their support. Prune older flowered side shoots back by two thirds of their length.
• Prune ornamental vines. Vines can produce growth of up to 10ft in one season so need to be kept in check. Thin out overcrowded shoots and then prune sideshoots to two buds from the main stems that are kept as a framework.
• Keep cutting back dead foliage and keep an eye out for weeds if it is mild.
• Apply dry mulch such as chipped bark around borderline-hardy plants such as agapanthus, phygelius, hedychium and melianthus to protect the crown. With other tender plants, fleece is very effective, but if you prefer something less obtrusive, a circle of wire netting filled with bracken or leaves will keep the cold at bay.
• Keep on top of weeding – if weather is mild they will still be growing.
• Plant evergreen shrubs if conditions are dry

The kitchen garden

Vegetables

• Earth up spring cabbages and other winter brassicas to give them better anchorage in strong winds. Tall growing Brussels sprouts are particularly prone to this and may need a strong cane next to them.
• Remove yellowing leaves from Brussels sprouts regularly as these can get fungal diseases. Harvest sprouts from the stem upwards.
• Continue winter digging so the weather can break down the soil and make preparing seedbeds easier. Cover empty prepared vegetable beds with fleece or clear (not black) plastic, which will warm the soil so it is easier to work.
• Prepare a perennial vegetable bed which can be planted up with rhubarb crowns and asparagus crowns.

Salad & herbs

• Sow parsley, chives and basil indoors for windowsill picking.
  fruit
• Established blackcurrant plants can now be pruned to allow the young wood, which will bear most of the fruit, to start putting on growth in spring. All the buds that are intact should remain, but in the case of whitecurrants and redcurrants only the top four should be left, removing all the others.
• During winter pruning, do not forget to remove mummified fruit that remained on branches, ideally together with a short piece of the spur to which they are attached.
• Remove the netting from the top of fruit cages as heavy snow in winter can make it sag.
• Check stored apples and other stored fruits for signs of deterioration and remove any affected fruit.

harvesting

Here is what you could be picking and eating this time next year, or if you're an old hand, already are harvesting:

• Brassicas: kale, red and green cabbages and Brussels sprouts
  Roots: parsnips, last carrots, beetroot, celeriac (under straw), Jerusalem artichokes and salsify
• Salad: all hardy salad leaves eg. rocket, winter purslane, mustards and Florence fennel (under straw)
• Edible flowers: Violas
• Leafy greens: chard (may need a cloche) and perpetual spinach
  Squash: stored pumpkins and squash
• Stems: leeks
• Herbs: hardy cut-and-come again herbs (eg parsley, par-cel, coriander, chervil) and evergreens (eg rosemary, sage, bay and winter savory)
• If you planted new potatoes in September, then December is the time to start lifting them, making sure you save some for Christmas Day.
• Edible crops from the store:
  
• Roots: beetroot, carrots, turnips and maincrop potatoes
  
• Fruit and nuts: long-storing apples (eg Braeburn), pears, quinces, walnuts, plus squash

General maintenance

• Continue collecting leaves from borders, paths and lawns. Keep them in wire cages or leafmould bags to rot down and produce useful leaf mould.
• Clean paths to prevent then becoming slippery and repair sheds, fences and trellises.
• Repair lawns if weather conditions allow.
• Carry out winter digging, incorporating organic matter so that the action of frost can breakdown the soil before spring making preparing seedbeds easier in the spring.
• Protect plants vulnerable to frosts as the year enters its coldest phase. Either bring in tender plants if you haven’t already and put mulch, compost or straw over the top of any in borders.
• Keep an eye on container plants and bulbs. Do not allow them to dry out after freezing.
• Raise potted plants off the ground to prevent them becoming waterlogged.
  If you haven't already done so, aerate your lawn before winter wet really sets in. You can use either a lawn aerator or simply insert a garden fork at regular intervals and rock it backwards and forwards a little to let air in.
• Avoid walking on lawns covered with frost.
• Wash, dry and store any used pots, seed trays and containers to remove overwintering pests and diseases.
• Check your notes before compiling your seed order to make sure you don’t forget that good idea you had back in May.

In the greenhouse

• heaters are working. Remove leaves from greenhouse gutters.
• Wash greenhouses, cold frames and cloches to let in more light. On warm days you may still need to ventilate the greenhouse.
• Water overwintering plants sparingly to avoid the risk of rot. Try not to wet the leaves when watering to avoid fungal diseases developing.

Wildlife & pests

• Feed birds in colder weather.
• Ensure you have berries for Christmas decorations by netting holly bunches to protect them from birds.
• Regularly wash and disinfect bird baths and feeders.
• Keep cutting back and clearing up any leaves so that slugs and snails can't shelter beneath them.
• Pests may overwinter on plants, so keep an eye out for infestations of greenfly and whitefly and red spider mite which can soon spread.