When to plant Tomatoes in Temperate Australia

Temperate zone — applies to Sydney, Melbourne, Adelaide, Perth, Newcastle and similar areas. Growing elsewhere? Cool · Subtropical · Tropical · Arid.

Sow tomatoes from August to November in temperate Australia, raising seedlings in punnets and transplanting them out once the frosts have finished. Seed germinates in 7–14 days somewhere warm, and depending on variety you will be picking fruit 49–119 days later — cherry types race ahead of the big beefsteaks. Give them the sunniest bed you have, deep soil enriched with compost, and 40–60 cm between plants so air can move through the foliage. The habit worth building early is deep, consistent watering rather than a little every day; it shows up months later as fewer split and blotchy fruit.

Sowing calendar — temperate zone

Green months are your sowing window: August to November.

Growing notes

Tomatoes are frost tender, and in temperate Australia the last frost typically lands around mid-October. That is why the seed goes into punnets from August — 10 mm deep, kept warm indoors or in a mini greenhouse — while the garden is still too cold. By the time seedlings are 15–20 cm tall and hardened off, the frost risk has passed and they can go out. A November sowing still works and gives you an autumn crop, but choose a faster variety so fruit ripens before the weather turns in May.

Position and soil matter more than most people allow. Full sun, at least six hours, in soil that drains freely and has had compost worked through it. Stake or cage at transplant time, not later, so you never spear the root ball. Water deeply two or three times a week at the base of the plant, and mulch to keep moisture even.

The most common failure is blossom end rot — a sunken black patch on the bottom of the fruit. It is not a disease but a calcium supply problem caused by erratic watering, so the fix is boring: even moisture, mulch, and no long dry spells followed by a flood. Planting out too early into cold soil is the other classic mistake; a chilled tomato sulks for weeks and is quickly overtaken by one planted later.

Tomatoes at a glance

Companion planting

Grows well with

Basil: Repels aphids and tomato hornworm; may improve flavour

Marigold: Root secretions repel nematodes; deters whitefly

Nasturtiums: Trap crop for aphids; lures them away from tomatoes

Keep away from

Fennel: Releases allelopathic compounds that inhibit tomato growth

Broccoli: Brassicas and tomatoes compete for same nutrients; inhibit each other

Cabbage: Brassicas inhibit tomato growth

Common questions

When should I plant tomatoes in temperate Australia?

Sow seed from August to November, raising seedlings in punnets and transplanting after the last frost, which is typically around mid-October in temperate areas. Seedlings started in August are usually ready to plant out just as the frost risk ends.

How long do tomatoes take to grow from seed?

Seed germinates in 7–14 days, and plants take 49–119 days to reach maturity depending on variety. Cherry tomatoes sit at the fast end of that range, while large heirloom and beefsteak types take longest.

Why do my tomatoes have black patches on the bottom?

That is blossom end rot, caused by inconsistent watering interfering with calcium uptake rather than by disease. Water deeply and regularly, mulch well, and the problem usually disappears on newer fruit.

Can I sow tomato seed straight into the garden?

In a temperate climate it is much more reliable to raise seedlings and transplant. Direct-sown seed sits in cold spring soil, germinates slowly and loses weeks compared with a punnet raised somewhere warm.

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