Basic Sowing Information for the Species Common/Latin Name: French, Triploid and American Type: Tender annual Temperature: 20-25°C Cover: Average layer vermiculite or compost Date: Sow early Feb. onwards Advice: Remove seed tray cover at first sign of seed germination. Sow French & Triploid Marigolds 8 weeks before they are required in flower. African or American Marigolds sow before mid February for plants in colour after last frosts.