Glasshouse & indoor

  • To help ripening of crops remove shading as light levels fall
  • Plant prepared hyacinth bulbs for Christmas in pots
  • Reduce watering of Hippeastrum (amaryllis) to give the bulbs a resting period
  • Continue harvesting tomatoes, peppers and aubergines

Ponds and water features

  • Thin out oxygenating plants. Leave on side of the pond to allow wildlife to crawl back
  • Where possible cover the pond with netting to prevent leaves falling in and rotting in the water.
  • Continue removing blanket weed and duckweed
Seasonal jobs for the month: December

1. When buying living Christmas trees to keep long term, check if it is container grown as their needles will last longer than cut trees.
2. To prolong display of Christmas gift plants such as azaleas (Indian hybrids), cyclamen (Cyclamen persicum) and especially forced bulbs such as daffodils and hyacinths keep the plants cool.
3. Gradually increase watering of rested or semi-dormant Hippeastrum (often incorrectly sold as Amaryllis) or plant new bulbs with two thirds of the bulb above the compost surface. Keep at 15-18° (59-65°F).
4. To force rhubarb to crop two to three weeks early cover the crowns with a layer of straw or bracken and cover over with a clay rhubarb pot to exclude light.
5. Drain hosepipes and automatic watering systems and store watering attachments in a frost free place to protect them from frost damage.

Lawn

  • To establish new lawns sow seed or lay turf
  • Apply autumn law treatments with moss killers or proprietary moss killers
  • Apply biological control (nematodes) against leather jackets and chafer grubs in lawns
  • Consider planting bulbs such as C. tommasinianus, Chionodoxa luciliae, Narcissus 'February Gold' and Scilla siberica for naturalising in lawn

Kitchen garden

  • Plant out spring cabbage
  • Plant onion sets suitable for overwintering
  • Continue harvesting apples and pears
  • For best choice order bare root fruit trees and bushes early
  • Continue picking autumn raspberries and blackberries
  • Reduce damage to ripening marrows, pumpkins and squashes by placing the fruit on wooden boards or tiles

Ornamental garden

  • Plant new and divide well established clumps of hardy perennials
  • Clear gone over summer bedding and prepare ground for winter bedding/spring bulbs
  • Stop feeding hardy garden plants
  • Plant spring flowering bulbs in borders and containers
  • Move evergreen shrubs

Pest and diseases

  • Remove fruit affected with brown rot
  • Bright orange, raised spots (pustules) on leaves of leeks and chives are caused by leek rust
  • Keep leeks protected with enviromesh or fleece against leaf mining fly and leek moth.
  • Do not compost blight affected foliage and tubers of potatoes and tomato plants and fruit
  • Clumps of honey coloured toadstools at the base of trees and shrubs may indicate honey fungus