when to plant marigolds in Brisbane

You can sow from July right through to February, covering most of the year outside the coolest weeks. They germinate in 5–10 days and flower in 50–70 days, so successive sowings keep colour going almost continuously.

do marigolds really repel pests in the vegetable garden

Yes, particularly French marigolds. Their root secretions suppress root-knot nematodes in the soil over a growing season, and the flowers help deter whitefly, aphids and cabbage moth around tomatoes, beans and brassicas.

why are my marigold flowers going mouldy

In humid subtropical weather, spent flowers develop grey botrytis mould and leaves can get powdery mildew. Space plants for airflow, water at the base in the morning, and dead-head spent blooms promptly so they don't rot against the foliage.

how far apart should I plant marigolds

Space plants 20–30 cm apart with rows about 30 cm apart. That spacing keeps air moving between plants, which matters in the subtropics where crowding invites fungal disease.

When to plant Marigold in Subtropical Australia

Sow marigold in subtropical Australia from July to February. Method: raise seedlings,sow direct. Seeds germinate in 5-10 days, with harvest roughly 50-70 days after sowing.

Subtropical zone — applies to Brisbane, Gold Coast, Sunshine Coast, Coffs Harbour, Lismore and similar areas. Growing elsewhere? Temperate · Cool · Tropical · Arid.

Sow marigold direct across a long season in the subtropics, from July to December and again in January and February, dropping seed 5–8 mm deep into warm soil. These fast, frost-tender flowers germinate in just 5–10 days and reach maturity in 50–70 days, so you can slot successive sowings around Brisbane and the Gold Coast for near year-round colour outside the coldest weeks. Space plants 20–30 cm apart with rows 30 cm apart. Beyond their bright orange and yellow blooms, marigolds earn their keep as companions, with root secretions that suppress root-knot nematodes and flowers that deter whitefly and aphids around tomatoes, basil, beans and brassicas.

Sowing calendar — subtropical zone

Green months are your sowing window: July to February.

Growing notes

Marigolds are one of the easiest flowers to grow in the subtropics, which makes them a reliable filler and companion in beds around the Sunshine Coast and Lismore. They love warmth and full sun, germinate quickly and shrug off the heat, so the main job is managing moisture and humidity rather than coaxing them along.

The classic failure here is fungal disease in the wet. In sustained humidity, marigolds pick up powdery mildew and grey botrytis mould on spent flowers, and lower leaves can develop leaf spot. Head this off by spacing plants at the full 20–30 cm for airflow, watering at the base in the morning, and dead-heading regularly so rotting flowerheads don't sit wet against the foliage. Spider mites can also flare in hot, dry spells, showing as fine stippling on the leaves.

Use their companion strengths deliberately: interplant French marigolds through tomato, bean and brassica beds, where root exudates suppress root-knot nematodes over a season and the scent deters whitefly, aphids and cabbage moth. Pair them with basil for a potent pest-repellent duo. Regular dead-heading keeps plants blooming for months.

Marigold at a glance

Sowing depth	5-8 mm
Plant spacing	20-30 cm
Row spacing	30 cm
Germination	5-10 days
Days to maturity	50-70 days
Frost tolerance	Frost Tender
Method	Raise Seedlings,Sow Direct

Companion planting

Grows well with

Tomatoes Basil Tomatoes Bean (Bush)Broccoli Cabbage Broccoli Cabbage Cauliflower Kale Bean (Bush)Cucumber Potato Pumpkin Zucchini Strawberries Eggplant Capsicum

Tomatoes: Root secretions repel nematodes; deters whitefly

Basil: Together a potent natural pest repellant

Tomatoes: Root exudates suppress root-knot nematodes in soil

Common questions

when to plant marigolds in Brisbane: You can sow from July right through to February, covering most of the year outside the coolest weeks. They germinate in 5–10 days and flower in 50–70 days, so successive sowings keep colour going almost continuously.
do marigolds really repel pests in the vegetable garden: Yes, particularly French marigolds. Their root secretions suppress root-knot nematodes in the soil over a growing season, and the flowers help deter whitefly, aphids and cabbage moth around tomatoes, beans and brassicas.
why are my marigold flowers going mouldy: In humid subtropical weather, spent flowers develop grey botrytis mould and leaves can get powdery mildew. Space plants for airflow, water at the base in the morning, and dead-head spent blooms promptly so they don't rot against the foliage.
how far apart should I plant marigolds: Space plants 20–30 cm apart with rows about 30 cm apart. That spacing keeps air moving between plants, which matters in the subtropics where crowding invites fungal disease.

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