When to Plant Sweet Corn in Canberra, Cold / Highland Guide
Also called corn, maize.
Soil temperature is modelled from Open-Meteo forecast (Canberra), not a live sensor.
What this month normally looks like in Cold / Highland
In October the Cold / Highland zone normally runs 20°C by day and 7°C overnight, with about 58 mm of rain over 7 or 8 wet days. The coldest October night on record across the zone was -6.4°C, so a late frost is not out of the question. Averages 1991 to 2026, 15 postcodes, SILO.
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This Sweet Corn guide is written for the Cold / Highland zone, which takes in Canberra, Cooma and Bright. Somewhere else? Your postcode picks the right one.
Not your zone? Cairns Brisbane Sydney Melbourne Alice Springs Perth
Also handy: will it frost this week? and what grows in shade.
- Planting window
- Oct to Dec
- Days to harvest
- about 11 weeks
- Sun
- Full sun to part shade
- Spacing
- 30 cm apart
- Soil pH
- 5.8–7.0
- Shop price
- $11.26/kg
Sweet corn is a warm-season grass requiring block planting for wind pollination. Freshly picked corn is dramatically sweeter than shop-bought because sugars convert to starch within hours of picking.
Published · By GardenBuddy.au
Planting dates, current conditions and prices on this page update daily.
Photo: Wikimedia Commons
Planting Calendar for Cold / Highland
- Jan -
- Feb -
- Mar -
- Apr -
- May -
- Jun -
- Jul -
- Aug -
- Sep -
- Oct S
- Nov S/T/D
- Dec T/D
S = Seed Tray T = Transplant D = Direct Sow
Want a nudge when it is sowing time?
One email a week with what is worth planting in the Cold / Highland zone right now, Sweet Corn included, plus which veg has jumped in price at the supermarket. Free, and you can stop it in one click.
How to Grow Sweet Corn in Cold / Highland Australia
- Soil
- Deep, fertile, well-drained soil enriched with compost and aged manure. Heavy feeder.
- Salt
- Moderately sensitive. Copes with a little salt, but the harvest drops on salty bore water.
- pH Range
- 5.8-7.0
- Sunlight
- Full sun (minimum 8 hours). No shade tolerance.
- Spacing
- 30cm apart, 60cm between rows
- Watering
- Deep water 2-3 times weekly. CRITICAL: increase at tasselling/silk stage. Water stress causes bare cob patches.
- Good companions
- Broad Beans (following season), Jerusalem artichoke (similar height/culture), Dwarf Beans, Cucumber, Peas
- Keep away from
- Celeriac, Celery (Listed under keep apart from celery. No reason is given.), Cherry, Chickpeas, Egyptian Spinach, Silverbeet (competes for nutrients), Tomato (shared corn earworm)
- Grow before it
- Leafy greens and brassicas (Lettuce, Silverbeet, Broccoli)
- Grow after it
- Roots and alliums (Carrot, Beetroot, Onion)
Give the bed 3 turns before other fruiting crops go back in. Corn, okra and sunflower are heavy feeders that sit with the fruiting crops in the cycle.
Cold / Highland Growing Tips for Sweet Corn
Recommended Varieties
- Golden Bantam (70 days)
- Early Gem (65 days)
Key Challenges
- Very short season
- Cool nights
- Narrow pollination window
Pro Tips
- 65-75 day varieties only
- Start indoors with heat
- Row covers first weeks
Pests and problems for Sweet Corn in Cold / Highland
- Corn Earworm and Fungal Infections Moderate
- Helicoverpa / Corn Earworm / Tomato Grub Watch
- Green Vegetable Bug Watch
- Wireworms Watch
- Cutworms Watch
- Common Rust Resistant varieties. Good spacing. Watch
- Northern Corn Leaf Blight Resistant varieties. Crop rotation. Remove old debris. Watch
Organic prevention (Corn Earworm (Helicoverpa)): Remove old plants. Crop rotation.
Harvesting Sweet Corn
When ready: Silks brown/dry. Cob full and firm through husk. Kernel exudes milky juice when pierced with thumbnail (milk stage).
How to harvest: Grasp cob, snap downward while twisting. Eat immediately. Sugar converts to starch within hours.
Storing and preserving sweet corn
How to keep it
- Freezing (blanched kernels). Husk, desilk. Blanch whole cobs 4-6 min. Ice bath. Cut kernels off. Freeze in portions. Keeps: 12 months.
- Freezing (on cob). Husk, desilk, blanch 4-6 min, ice bath, wrap individually, freeze. Keeps: 12 months.
- Corn Relish. Kernels + diced capsicum, onion, celery, mustard, vinegar, sugar. Simmer 30 min. Bottle hot. Keeps: 12 months.
Canning safety. Low-acid vegetables like sweet corn must be pressure canned, never water-bath canned.
Grow vs buy
A 2.4 m × 1.2 m bed fits 12 plants, about $34 worth at today’s Aldi, Coles, IGA and Woolworths prices, checked today.
That is roughly 3 kg at $11.26 a kilo.
Draw your sweet corn bed → No account needed.
What sweet corn costs in the shops right now, retailer by retailer, updated daily.
What members get
- Soil and weather from your nearest station
- An email when it's time to sow
- Your own garden plan, including planning from a photo
- Price history and price alerts
- Pest risk alerts for your area
- Full salt and canning detail
Common Questions About Sweet Corn
When do you plant sweet corn in Australia?
It depends on your climate zone, not the calendar month alone. Planting months by zone:
- Tropical (Cairns): Mar to Sep
- Subtropical (Brisbane): Jan to Feb, Sep to Dec
- Warm Temperate (Sydney): Jan, Sep to Dec
- Cool Temperate (Melbourne): Oct to Dec
- Cold / Highland (Canberra): Oct to Dec
- Arid / Semi-Arid (Alice Springs): Jan, Aug to Oct, Dec
- Mediterranean (Perth): Jan, Sep to Dec
Can you grow sweet corn all year round in Canberra?
No. In the Cold / Highland zone the planting months are Oct to Dec. Outside that window it either bolts, sulks or gets cut down by the weather.
What else is sweet corn called?
Sweet corn is the usual Australian name. Overseas seed packets and recipes call it corn, maize. Same plant, same growing advice.
When should I plant Sweet Corn in Canberra?
Sow once frost has passed and soil is warm, in two or three plantings three weeks apart. January sowings often fail to finish before autumn frost.
What soil temperature do Sweet Corn need?
Sweet Corn germinate best when soil temperature is between 16°C and 35°C.
How do I know when Sweet Corn are ready to harvest?
Silks brown/dry. Cob full and firm through husk. Kernel exudes milky juice when pierced with thumbnail (milk stage).
What are the best Sweet Corn varieties for Canberra?
Recommended varieties for the Cold / Highland zone include: Golden Bantam (70 days), Early Gem (65 days).
What grows well with Sweet Corn?
Good companion plants for Sweet Corn include: Broad Beans, Jerusalem artichoke, Dwarf Beans, Cucumber, Peas.
Are sweet corn salt tolerant?
Only a little. Sweet corn are moderately sensitive to salt, so the harvest drops on salty bore water. Mix salty water with rainwater, and mulch the bed.
Which zone am I in?
Type your postcode into the box near the top of the page and it tells you, and links this crop in your own zone if it differs. Or look it up on the grow zone map. This page is the Cold / Highland zone, Canberra is its reference city.