When to Plant Marigolds & When Do They Bloom?

Planting Time

• Marigolds may be sown indoors or outdoors. Only sow seeds outdoors in spring once the threat of frost passes and the soil warms to at least 70 degrees Fahrenheit. Continue to successively sow seeds into summer or fall as long as there is at least 80 days before the expected first frost. For faster flowering, you may sow marigold seeds in soil-filled trays indoors four weeks before the last spring frost date in your region. The seedlings germinate and grow to 2 to 4 inches tall before being transplanted outdoors into a garden bed.

Marigold Development

• The quill-shaped black and white seeds of marigolds sprout within 7 to 10 days after being planted in evenly moist, warm soil. Depending on variety, the first flower buds occur on stem tips anytime after 6 to 8 weeks of growth in a warm, sunny location. Once of an age and size to flower, marigold plants continue to produce flowers over 10 to 15 weeks. Promptly removing old, waning flower heads--called deadheading--encourages plants to produce more flowers.

Types

• Even though native to Central America, marigolds are referred to as being either French or African. French marigolds (Tagetes patula) remain small at maturity, growing only 6 to 12 inches tall in a rounded, bushy habit. African or American marigolds (Tagetes erecta), by contrast, grow upright and taller, from 24 to 36 inches tall. Consult seed packets for specific variety information on marigolds, as some may mature more quickly and being producing flowers sooner than those that grow tall before the first buds appear.

Sowing Marigold Seeds

• Plant marigold seeds, regardless of variety, between 1/4 and 1/2 inch deep. If directly sowing into a row, space seeds every 4 inches in the furrow. Once plants germinate, you can thin out plants so they have ample space between them to grow to their mature sizes. Pulling up seedlings during thinning may be immediately transplanted into bare spots in the row to continue to grow.