Climate Notes
- Average max temp: 26–30°C
- Average min temp: 18–20°C
- Soil: warm and moist
- Frost: unlikely in December, but heavy mulching is good for moisture retention
Vegetables
Direct Sowing (Seeds)
- Beans: bush & climbing varieties
- Fast-growing, heat-tolerant
- Space climbing beans with trellis
- Corn (Sweet Corn): block plant for pollination
- Cucumbers & Zucchini: all summer varieties
- Pumpkin & Squash: Grey Crown, Butternut, Delilah F1
- Capsicum & Chillies: can also start from seeds (warm soil)
- Okra: loves heat, sow directly
- Lettuces & Asian greens: fast-growing, but watch for bolting in heat
- Radish & Turnip: quick harvest, good as filler between longer crops
Seedlings / Transplants
- Tomatoes: cherry, salad, or Roma types
- Eggplant / Aubergine: loves full sun and warmth
- Capsicum & Chilli: if not sown as seeds
- Brassicas (Broccoli, Cauliflower): can be started, but in very warm December, bolt risk high — consider starting in shade
Herbs
- Basil: Thai, Sweet Genovese
- Coriander / Cilantro: best in part shade to prevent bolting
- Chives: cut-and-come-again
- Oregano & Thyme: plant from seedlings or cuttings
- Mint: keep in pot — spreads aggressively
Fruits / Small Plants
- Strawberries: start runners in raised beds or pots
- Passionfruit: plant seedlings; provide trellis
- Blueberries: transplant container-grown plants
- Citrus: lemons, limes, mandarins — plant small trees or seedlings
Planting Tips for December
- Watering:
- Soil dries quickly in summer heat → mulch heavily
- Water early morning or late afternoon to avoid evaporation
- Soil:
- Add compost or worm castings before planting
- Ensure good drainage for root crops
- Sun:
- Most summer vegetables need 6–8 hours full sun
- Herbs like coriander prefer partial shade in hottest part of day
- Pests:
- Slugs, snails, and caterpillars increase in summer → check regularly
- Use netting or row covers for young seedlings if birds or insects are a problem
- Succession Planting:
- Sow a small patch every 2–3 weeks for continuous harvest
- Companion Planting:
- Corn + beans + pumpkin guilds are ideal
- Basil near tomatoes can improve flavour and repel pests
Have you ever heard or tried “Three Sisters” system/method in your vegetable garden?
What are the benefits?
- The fast-growing corn provides sturdy support for the young climbing beans.
- As the beans grow, their spiralling stems strengthen the sweet corn plants in readiness for their heavy mature cobs.
- As with all legumes, the climbing beans fix nitrogen from the air into the soil, acting as a natural fertiliser for the corn and squash.
- The large leaves of the squash plants shade the ground, acting as a natural mulch to keep the soil moist while also crowding out weeds.
- Lastly, the tough squash leaves also act as a physical barrier to the more tender stems of beans, keeping out many pests
What are the planting methods?
The Three Sisters is a flexible planting method which can be scaled up and down as needed. However, the traditional way gives excellent results if you have the right space and location.
- Build circular raised beds approximately 30cm high by 120cm across.
- Mix in plenty of compost and organic fertiliser to fuel the first year’s growth, until the beans can work their nitrogen magic on the soil for later crops.
- In mid to late spring, plant around half a dozen sweet corn seeds or hardened-off young plants in a circle about half way into the raised bed.
- When the maize is around 10-12cm in height, add four bean seeds around each young plant.
- Shortly after the beans have germinated, add half a dozen pumpkin or zucchini seeds placed in a circle, between the sweet corn plants and the edge of the mound.
- Keep the beds watered well while avoiding splashing the squash plants, weed as necessary, and feed regularly with a general purpose vegetable feed.
Currently, I am trying the system with much excitement and frustration. My two sisters (pumpkins and beans) are growing very well with good quality home-made compost. However, sweet corn seedlings are constantly getting eaten by unknown creatures overnight. Yes, I’m frustrated but determined to achieve the result. Hope you are convinced about the rationale behind the system and have much fun as you try. Let me know how your system is going/went next time when you see me.
Seed Bank Needs
- Mild chilli varieties / Capsicum varieties
- Beetroot
- Cape Gooseberry
- Chervil
- Kale varieties
- Oregano
- Onions
- Spaghetti Squash
- Paw Paw or Papaya
- Broccoli
- Sorrel (green or red veined)
- Broadbeans
- Warrigal greens ( low stock)
- Land cress
- Mullein
- Chives
- Garlic chives
- Silverbeet and rainbow chard
- Spinach
- Rhubarb
- Radish varieties
- Eggplant varieties
- Rocket
- Dill
- Chinese cabbage
- Mustard varieties
Accessing the Seed Bank
The seed bank is available at every gathering. Remember, if you take seeds, you’re expected to grow them and allow one of the best plants to produce seeds for donation back to the bank. This keeps our seed bank free for members, increases diversity, and ensures plants are well-suited to our Central Coast microclimate.
Seed donations should include details on seed type, suburb grown, and harvest date. For private arrangements to access the seed bank, please contact Joanne Cho via Facebook Messenger.
Happy gardening and seed saving!
