When to plant Nasturtiums in Arid Australia

Arid zone — applies to Alice Springs, Mildura, Broken Hill, Kalgoorlie, Port Augusta and similar areas. Growing elsewhere? Temperate · Cool · Subtropical · Tropical.

Sow nasturtiums direct from March to October, dropping the large seeds 10-15 mm deep where you want them to grow. In arid gardens like Alice Springs and Mildura they resent the peak of summer, so autumn and the cool end of spring give the steadiest results. Germination takes 14-21 days, and plants reach flowering maturity in about 70-80 days. Space them 20-40 cm apart, with rows around 30 cm, and let them ramble over the edge of a bed or trail from a pot. Both the peppery leaves and the flowers are edible, so a single sowing earns its keep twice over.

Sowing calendar — arid zone

Green months are your sowing window: March to October.

Growing notes

Nasturtiums are one of the easier flowers to keep alive in the desert, but the enemy here is not cold, it is the combination of 40°C afternoons and dry wind. Plants that look lush in April will crisp and stall by midsummer, so time your main sowing for autumn or very early spring and give them a spot that catches morning sun but some afternoon shade in Broken Hill or Port Augusta.

The most common failure is a wall of leaf and no flowers. This almost always means the soil is too rich or too heavily fed with nitrogen. Nasturtiums flower best in lean, unimproved ground, so skip the fertiliser and let them fend for themselves.

The second issue is aphids, which cluster on new growth once the weather warms. This is actually part of their value as a trap crop near tomatoes and brassicas, but if the colony gets heavy, blast it off with a hose or squash it by hand rather than spraying, since you may want to eat the plant. Deep, infrequent watering and a good mulch layer keep the roots cool and the plants cropping for longer through the dry.

Nasturtiums at a glance

Companion planting

Grows well with

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

Broccoli: Trap crop for cabbage white butterfly caterpillars

Cabbage: Trap crop lures cabbage white away from brassica

Common questions

when to plant nasturtium seeds in Alice Springs

Sow them direct from March through October, avoiding the harshest summer months. Autumn sowings establish before the cold desert nights arrive, while an early spring sowing flowers before the real heat sets in.

why is my nasturtium all leaves and no flowers

Too much nitrogen is the usual cause. Nasturtiums flower best in poor soil, so stop feeding them and let the ground stay lean, and blooms will follow within a few weeks.

do nasturtiums survive summer in the desert

They struggle through 40°C heat and dry wind, often stalling by midsummer. Give them afternoon shade, deep mulch and regular water, or simply treat them as a cool-season flower and resow in autumn.

how deep do you plant nasturtium seeds

Sow the large seeds 10-15 mm deep, directly where they are to grow. They dislike transplanting, so avoid raising them in punnets.

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