Your organic garden in December and January

As winter starts to bite, cover tender plants to protect them from frost damage.

Most pests will be inactive in cold spells, but it’s still worth checking for snails etc in sheltered places, such as empty pots in the cold frame or greenhouse.

Enjoy the dark evenings by browsing your Organic Gardening Catalogue to choose next season’s seeds. Why not try something new this year?

See below for advice on soil, vegetables, fruit, herbs and flowers as well as the greenhouse and conservatory and ponds.

Where you see the sign FS, Garden Organic members can check the relevant Fact Sheet for further information. Want to become a member? Join here, for just £2.75 a month, and enjoy the full benefits.

Soil

  • Protect bare soil during the winter months. Use autumn leaves as a mulch (cover) during winter weather. If necessary, cover with netting or fleece to prevent wind blowing everything away.
  • Don’t stop weeding. Hoe off/pull out any annual weeds, and dig out perennial ones that are revealed. Compost green foliage, but not seedheads nor perennial weed roots.
  • Keep off wet soil in all parts of the garden to avoid compacting and damaging the structure. If you absolutely have to walk on it in the wet, stand on a plank to spread your weight. This is especially important for clay soil.
  • Continue to collect fallen autumn leaves to make leafmould. Pile them in large bin bags or heaps, keeping them damp. See Leafmould

Composting

  • Add enough dry waste to balance the large amounts of wet waste coming out of the kitchen just now. Scrumpled up Christmas card envelopes and bits of cardboard are very useful to provide the carbon element needed.
  • Aerate your compost heap by turning it
  • For advice on composting see Home Composting
  • Worm bins kept outside need to be well-insulated to help the worms survive winter conditions. Reduce feeding in cold weather, as the worms will not consume very much at this time. FS Worm composting

Vegetables

  • Garlic can be planted until March.
  • Prepare a ‘compost trench’ using the old stems from Brussels sprouts, kale and other tough brassicas once cropping finishes. The trench should be about a spade’s depth, and positioned where runner beans, or other peas and beans will grow next year. Lay the stems along the bottom of the trench, and then roughly chop them up with a sharp spade. Other uncooked vegetable scraps can also be added. As the veg waste reaches the top of the trench, cover over with soil.
  • Make comfrey leafmould. Cut 2/3rds of the plant's leaves (leaving the remainder to die down and feed back into the comfrey plant) and fill a container (such as a dustbin) in alternating layers of leafmould and chopped comfrey leaves. This will take up to 18 months to rot down, but it is an excellent medium for seed planting. See Leafmould
  • Start planning your crop rotation for next season’s vegetable plot. If you already have a rotation plan, just make a note of where next year's crops will go. If this is your first year, make a list of all the vegetables you would like to grow, then check out our guide to planning your planting
  • January seed sowing - try some early sowings in trays. Germination temperatures of around 13°C are adequate, so you need a bright, cool windowsill. Try lettuce, summer cabbage and cauliflowers, plus round varieties of carrots, spinach, salad onions and turnips. If you have a heated greenhouse you can sow greenhouse tomatoes as early as January. See the Organic Gardening Catalogue for varieties.

Pest & disease watch

  • If your leeks, onions or other alliums were attacked by leek moth or allium leaf miner, dig over the plots so the birds can feed on any over-wintering pests in the soil.
  • Comfrey rust can be a major problem if it takes hold. If necessary, remove plants completely and re-place with new stock next year.
  • Remove and compost dead and yellowing leaves from winter brassicas. They can encourage fungal diseases and harbour pests.

Fruit

Tree ties

  • Check the condition of all stakes, supports, ties and rabbit guards for trees. Look for wind rocking or constriction. If this has happened, replace stakes and renew ties.
  • Continue to plant new trees and bushes supplied as ‘bare rootstock’. See How to Grow Fruit. Always use a new, clean spot, not the where the same plants have just been growing, to avoid 'specific replant disease'. If there is no alternative, backfill the hole with fresh soil mixed with manure, garden-made compost or mycorrhizal fungi. The latter, sold as ‘Rootgrow’ is available from The Organic Gardening Catalogue.
  • Cut out dead, dying or infected disease branches from apple and pear trees. Do not be tempted to prune the stone fruits (apricots, cherries, plums etc) until May when risk of silver leaf infection is past.
  • Clear competitive growth (weeds and grass) from around fruit trees, especially newly planted and young trees.

Pest & disease watch

  • Pick every last fruit off fruit trees. Fruit hanging on trees over winter is one of the main sources of brown rot infection in the spring. Infected fruit can be composted safely.
  • If your fan-trained peaches/nectarines have been affected by peach leaf curl, build a rainproof structure to protect them. It needs to be in place before buds start to grow as over-wintering disease spores are spread by rain splashes. A simple frame supporting a plastic sheet to keep the plant dry is all that is required.
  • Check grease bands are still sticky and in place around fruit trees and stakes to give control against winter moth, plum fruit moth and March moth. Replace where necessary.
  • Check rabbit guards too
  • Entice birds into the garden to eat winter aphids with fat balls hanging in trees or suspended from bamboo canes set among fruit bushes and canes.
  • Inspect apples trees for woolly aphids. Look for a whitish fluffy coating (pictured) where branches join the trunk and cracks in the bark.

Woolly aphid

Herbs

  • Remove fallen autumn leaves that are covering low-growing herbs such as thyme. This will prevent the plants being smothered and possibly killed by a blanket of wet foliage.
  • Look for bay tree leaf edges thickened and curled over. The sucker nymphs live there under a white woolly wax. Remove all affected leaves and clear away any leaf litter at the base of trees where adults will over-winter. Don’t throw leaves in the compost heap, put all material into the green waste bin.

Flowers

  • Winter pansies can be affected by Downy mildew and leaf spots. Deadhead regularly and remove diseased leaves on sight.
  • Plan next year’s garden now. Try to have something in flower year-round, which is essential for the wildlife that plays such an important role in keeping your organic garden healthy.

Keeping the growing area healthy

  • Spider nests are everywhere at the moment, filled with eggs ready to hatch next May. The baby spiders appear just as their prey does, and hungry spiders will consume vast quantities of insects, so nurture these predators-to-be.
  • Entice hungry birds into your area with fat balls and other bird feeding stations. They will repay you by eating up a lot of insect pests that lurk out of our sight and reach, under buds and on stems. Birds are especially helpful in cleaning up over-wintering aphids in fruit trees and bushes.

Greenhouse

  • Remove dead/dying foliage regularly from over-wintering plants to prevent mildews and moulds taking hold.
  • Whitefly will often colonise over-wintering potted-up fuchsia plants. Use insecticidal soap to keep things under control; it’s too cold now to use the biological control. If plants are badly infested, carry them outside very carefully in order not to disturb the whitefly. Once outside shake vigorously to dislodge the insects and quickly replace back inside the greenhouse and shut the door.

Ponds

  • Ponds are best left alone at this time of year as frogs and other creatures are hibernating, and should not be disturbed.
  • Gently skim off dead leaves and duckweed. Even in winter invasive plants can multiply.

Houseplants

  • Reduce watering now as plants aren’t growing much, and leaves don’t lose moisture in cool conditions. Keep plants just moist.
  • No need to feed plants between now and March.
  • Mist the underside of leaves to keep humidity high. This deters red spider mite. The Organic Gardening Catalogue has a range of pest controls suitable for houseplants.