When to plant African Marigold in Temperate Australia

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

Sow African marigold direct from July to December, dropping seed 8–12 mm deep once the soil is workable and warming. Germination takes 14–28 days, so be patient through the cooler end of that window and expect faster strikes as spring settles in around Sydney and Adelaide. Thin or space plants 20–40 cm apart in full sun; they reach flowering maturity in roughly 80–90 days. These are frost-tender annuals, so the July and August sowings are best raised in a sheltered spot or under a cloche until mid-October frost risk has passed, while November and December sowings can go straight into open beds.

Sowing calendar — temperate zone

Green months are your sowing window: July to December.

Growing notes

African marigolds are among the easiest flowers to grow in a temperate garden, asking little more than sun, drainage and the occasional deep water. The bright pompom heads keep coming from late spring right through to the first autumn frosts, and they earn their place near vegetable beds by drawing hoverflies and other beneficial insects.

The most common failure here is damping-off and slow, patchy germination when you sow too early into cold, wet ground. If your July or August seedlings rot at the base or simply sit and sulk, you have sown into soil that is still too cold. The fix is to start those early batches in trays on a warm windowsill or in a glasshouse, and only direct-sow outdoors once nights lift, which in Melbourne usually means waiting until October.

The other issue is powdery mildew and grey mould in a wet, crowded planting. Give each plant its full 20–40 cm of room so air moves freely, water at the base rather than over the foliage, and pinch out the growing tips early to build bushier, sturdier plants. Deadhead spent blooms regularly and the display will not flag until the cold returns.

African Marigold at a glance

Common questions

when to plant marigolds in Melbourne

In temperate Melbourne, sow from July to December, but treat the July and August sowings as protected batches raised under cover. Direct sowing into open beds is safest from October once frost risk has passed. This gives you flowers from late spring through to autumn.

how deep to sow marigold seeds

Sow African marigold seed 8–12 mm deep into moist, well-drained soil. Cover lightly and keep the surface damp until seedlings appear, which takes 14–28 days. Firm the soil gently over the seed to keep it in contact with moisture.

do marigolds need full sun

Yes, African marigolds flower best in full sun and become leggy and sparse in shade. Choose the brightest bed you have and space plants 20–40 cm apart so each gets good light and airflow.

why are my marigold seeds not germinating

The usual cause is soil that is still too cold, especially with early July or August sowings. Germination can take up to 28 days even in good conditions, so wait it out, and start early batches in warm trays indoors rather than direct in cold ground.

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