What to do & plant in your garden in December — Southern Hemisphere’s summer.
Your edible garden will be starting to overflow, with summer harvests readying. Things like new potatoes and berries should be ready in time for the Christmas spread.
Watering will become essential for those with vegetable gardens, young plants, grass that you want to keep green and especially for your potted plants.
Summer holidays — If you’re going away
If you are going to be away over the summer break, harvest as much as you can before you leave.
Weed, feed and water well before you go too. Don’t sow seeds or plant any new seedlings/new plants until you get back — these guys need regular watering and attending to at this time of year.
General Gardening
Water
Get into a regular watering rhythm with your gardens, vegetable plots and especially your pot plants, which dry out faster than garden beds.
Plants are best watered in the morning (before 9am) or early evening (after 5pm), not during the searing heat of the day.
Avoid watering on windy days (as evaporation is accelerated).
Water deeply every few days (rather than a little every day) — this will encourage plants to develop deeper root systems, which are more drought-resistant. { More tips on watering here }
Mulch
We’ve said it a thousand times, and we’ll say it again — mulch, mulch, mulch.
At this time of year the purpose of mulch is to conserve moisture and protect a plant’s roots from the heat of the sun. Use pea straw, bark/wood chips, newspaper or shredded cardboard, grass clippings, seaweed, wool…
The Edible Garden
Harvest
The vegetable garden is starting to become super abundant. Harvest things regularly (and early) to encourage further crops to grow — leaving mature fruit on a plant tells it that it’s done producing and it won’t fruit any more.
- The first of your beans may be ready now
- You may be able to harvest early chillies and tomatoes
- Pick courgettes early (before they turn into marrows!)
- Dig up your new potatoes, fresh for the Christmas table
- Pick lettuces, herbs and salad leaves continuously so they don’t go bitter.
- Pick your ripe strawberries (before the birds get to them!)
— In the Vegetable Garden
- Continuously plant salad greens for a staggered harvest of salads and herbs through the summer — like mizuna, lettuce and mesclun
- Keep your tomatoes well watered, and continue removing laterals from them as they grow
- Protect your strawberries from birds as they start to ripen, and keep watering them well.
Prevent bolting
At this time of year, vegetables and herbs are really prone to going to seed. When the temperature changes suddenly, plants will often bolt.
They flower at this time to help the plant reproduce, instead of growing the leaves that you want to use in your salads and cooking. You end up with small, spindly plants that are too bitter to eat (coriander is notorious for this!).
To help avoid this — mulch well, water consistently (morning or evening), choose a spot with a more consistent temperature, keep plants well spaced, and plant bolting-prone plants in semi-shaded areas during summer.
What to plant in the vegetable garden in December
Roots —
- Beetroot
- Celeriac
- Radish
Tubers —
- Potatoes
Brassicas —
- Cabbage
- Cauliflower
Herbs —
- Basil
- Coriander
- Chervil
- Parsley
- Rosemary
- Thyme
Salad greens —
- Lettuces
- Mizuna
- Silverbeet
- Spinach
Other —
- Eggplant
- Capsicums
- Chillies
- Cucumber
- Florence fennel
- Leeks
- Spring onion
- Onions
- Pumpkin
- Sweetcorn
- Tomatoes
- Courgettes
Fruit —
- Avocado
- Citrus
- Passionfruit
- Tamarillo
- Melons
- Kiwifruit
- Grapes
- Berries
— In the Orchard
Plant
Plant avocados, grapes, kiwifruit, tamarillos and passionfruit.
Caring for your fruit trees
Keep your fruit trees, citrus and passionfruit well fed and watered. Mulch around the roots, keeping the mulch material away from the trunk.
Berries
Keep the scrambling berry plants, like boysenberries and blackberries, well staked and supported so berries can stay off the ground. You’ll be able to start harvesting blueberries, strawberries, boysenberries, blackberries and raspberries.
The Picking Garden
Plant
BULBS — dahlias
ANNUALS — nemesia, snapdragons, lobelia, zinnia, marigolds, nasturtiums, delphinium, cosmos, ageratum, nigella
PERENNIALS — echinacea, lavender, geranium, aster, calendula, alyssum, salvias, chrysanthemums, verbena, verbascum, bacopa, arctotis, penstemon
Plant for the bees
Plant things like alyssum, cosmos, echinacea, geranium, lavender and salvias. They love simple flowers.
{ For more information, read our pollinator articles }
Prune
Deadhead and cut back your roses before Christmas, to encourage another later summer flush of flowers of blooms.
Lift bulbs
If you’re planning on lifting and shifting your spring-flowering bulbs, lift them around now — when the leaves have completely died down. Store in a cool, dry place (for planting late autumn/winter).
