When to plant Squash in Temperate Australia

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

Sow squash direct from September to January, dropping two or three seeds 15-25 mm deep into warm soil once frost has passed, then thinning to the strongest seedling. Germination is quick at 6-18 days, and depending on type, plants crop in 50-90 days. Give each plant plenty of room, 60-100 cm apart with rows 90-100 cm apart, as squash sprawl generously. This is a frost-tender summer crop, so temperate gardeners in Melbourne, Adelaide and Newcastle should wait until mid-October, after the last frost, before sowing outdoors.

Sowing calendar — temperate zone

Green months are your sowing window: September to January.

Growing notes

Squash are hungry, thirsty, frost-tender plants that romp away once the soil warms. Prepare the bed with plenty of compost or aged manure and choose the sunniest spot you have. Sow direct rather than transplanting where possible, as they resent root disturbance, and hold off until frost danger has passed, since a single late frost kills young plants outright.

The classic failure in temperate gardens is powdery mildew, a white bloom that coats the leaves in late summer and shuts down the plant early. Water at the base rather than over the foliage, space plants for airflow, and remove the worst-affected leaves; a milk-and-water spray at first signs can slow it. A second common problem is fruit that starts to form then rots at the tip, which is poor pollination, often in cool or wet weather. Hand-pollinate by dabbing male flowers into females on cool mornings to guarantee a set.

Interplanting nasturtiums nearby helps, as they deter squash bugs and act as a trap crop for aphids. Keep the water up steadily through fruiting, mulch well to hold moisture in warm temperate summers, and pick young squash often, as regular harvesting keeps the plant producing for weeks.

Squash at a glance

Companion planting

Grows well with

Nasturtiums: Deters squash bugs; trap crop for aphids

Common questions

When can I plant squash in Melbourne?

Wait until after the last frost, from mid-October onward, and sow through to January. Melbourne's frosts can linger into October, so sowing too early risks losing young plants to cold.

Why is my squash fruit rotting at the end?

Small fruit that yellows and rots at the tip is usually poor pollination, common in cool or wet weather. Hand-pollinate by transferring pollen from male to female flowers on a mild morning.

How do I stop powdery mildew on squash?

Water at the base rather than over the leaves, space plants well for airflow, and remove badly affected foliage. A diluted milk spray at the first white patches can slow its spread in humid weather.

How far apart should I plant squash?

Space plants 60-100 cm apart with 90-100 cm between rows, as they sprawl widely. Bush types need less room than trailing kinds, but all appreciate space for airflow to reduce disease.

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