When to Sow Marigold Seeds for Best Results

Getting the sowing date right is one of the most important decisions you make with marigolds. Sow too early in cold conditions and seedlings sit in cold soil, make poor growth, and are vulnerable to damping off. Sow too late and you lose weeks of flowering. The right window depends on your variety, your climate, and whether you are sowing indoors or direct.

French Marigolds (Tagetes patula) — Sowing Dates

French marigolds are the fastest-maturing type — typically 8–10 weeks from sowing to first flower. In the UK and similar temperate climates, sow indoors on a warm windowsill from late March to mid-April for planting out after mid-May frosts. In warmer climates (USDA zones 9–11), direct sow outdoors from March onward. French marigolds can also be sown in July for an autumn display in mild areas. Their shorter growing season gives more flexibility than African types.

African Marigolds (Tagetes erecta) — Sowing Dates

African marigolds are slower, taking 10–14 weeks from sowing to flower. In the UK, sow under cover in late February or March for planting out in May. Starting too late means you spend much of summer waiting for blooms. In the US, sow 6–8 weeks before your last frost date. If you missed the early window, buy plug plants rather than starting from seed — this gets you flowering plants into the garden quickly without the long indoor wait.

Direct Sowing Outdoors

Both types can be sown direct into the soil once it is reliably warm — above 18°C at a depth of 2–3 cm. In the UK this is typically late May to early June; in warmer US climates, April or May. Thin seedlings to the correct spacing once they are large enough to handle. Direct-sown plants often catch up with indoor-sown ones because they avoid any transplant stress, but they will flower later in the season.

Signs You Sowed Too Early

Seedlings that germinate and then sit almost motionless, with yellow-tinged lower leaves and very slow growth, are usually in cold, wet conditions. If indoor temperatures drop below 15°C at night, seedlings stall. Use a heat mat under seed trays or move them somewhere warmer. Once soil temperature rises above 15°C, growth will resume.

Can You Sow in Summer?

A late sowing in June or early July works well for French marigolds in temperate climates, giving a display from late August through October. African marigolds sown in June rarely produce significant blooms before the first frost in northern gardens — they need too long a lead time. For a late summer and autumn display, stick to fast French or signet varieties if sowing after midsummer.