When to plant Cucumber in Temperate Australia

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

Cucumbers are sown direct from September to February in temperate Australia, 10 mm deep into soil that has properly warmed. Seedlings emerge in 10–15 days and fruit follows in 60–90 days, so even a February sowing can produce a late crop before the season closes. Plants want full sun, rich moist soil, spacing of 40–60 cm, and ideally a trellis — climbing keeps fruit straight, clean and easy to find, and halves the ground the vine occupies. Steady water is the other non-negotiable; it is what keeps the fruit sweet rather than bitter.

Sowing calendar — temperate zone

Green months are your sowing window: September to February.

Growing notes

Frost tender from seed to final fruit, cucumbers should not be direct-sown outdoors until the mid-October last frost has passed — the September start of the window really belongs to sowings under cover or in very sheltered gardens. From late October to December is prime time. January and February sowings still work because the crop needs only 60–90 days, but they are racing the May frosts and cooling autumn nights, so give them the warmest spot available.

Prepare a bed with plenty of compost, water it deeply, and sow a few seeds per station, thinning to the strongest. Train vines up a trellis or mesh from early on; ground-grown fruit curls, discolours where it touches soil, and hides under leaves until it turns into a yellow torpedo. Water deeply and regularly at the base — cucumbers are mostly water, and their two classic complaints both trace back to moisture and airflow.

The first is bitter fruit, caused by water stress: a vine that dries out concentrates cucurbitacins and the harvest turns bitter, so mulch well and never let the bed bake dry. The second is powdery mildew coating the leaves from late summer, which is slowed by watering at ground level, generous spacing, and good air movement through a trellised vine. Pick fruit young and often; every mature cucumber left on the vine tells the plant to stop producing.

Cucumber at a glance

Companion planting

Grows well with

Nasturtiums: Deters aphids and cucumber beetle; trap crop

Marigold: Deters nematodes and cucumber beetle

Borage: Deters tomato hornworm; attracts pollinators for better fruit set

Keep away from

Dill: Mature dill inhibits cucumber growth

Sage: Sage stunts cucumber growth

Potato: Both attract similar pests; disease spread risk

Common questions

When should I sow cucumbers in temperate Australia?

Sow direct from September to February, waiting until after the mid-October last frost for outdoor sowings. Late sowings in January or February still crop, since cucumbers need only 60–90 days to mature.

How long do cucumbers take to grow?

Seed germinates in 10–15 days and plants produce fruit 60–90 days from sowing. Picking regularly keeps the vine producing for weeks afterwards.

Why are my cucumbers bitter?

Bitterness comes from water stress — vines that dry out produce fruit high in bitter cucurbitacins. Deep, regular watering and a thick mulch keep the fruit mild.

Do cucumbers need a trellis?

They will sprawl on the ground, but a trellis produces straighter, cleaner fruit, better airflow against mildew, and uses far less space. Train the vine up from when it is young.

Why are my cucumber leaves turning white?

A white powdery coating is powdery mildew, which is almost inevitable on cucurbits by late summer. Water at the base rather than over the leaves, keep plants well spaced and trellised for airflow, and remove the worst-affected leaves.

Keep exploring