Can You Plant Marigolds in September?

Transplants

• Gardeners in areas with short growing seasons, or those who do not have the time to plant and nurture seeds, buy marigolds at nurseries and garden centers. These plants are then transferred into the garden, where they serve as border or bedding plants, or are interred in window boxes and containers. Transplants are normally interred as soon as the ground is workable, but can be planted at any time. In the southern hemisphere, the month of September is a good time to plant marigolds, but in the northern hemisphere, the month of September is late in the growing season. Waiting until the end of the growing season to purchase and plant marigolds is risky, as high-quality marigolds may not be available and the life of the plant, even a healthy one, is limited.

Seeds

• When growing marigolds from seed, allow 3 to 5 days for germination. Soil temperatures should be within 65 to 75 degrees Fahrenheit for seeds to germinate. Once germinated, marigolds take an additional 12 to 15 weeks to mature. The plants require minimum temperatures of 60 degrees in order to flower. Cooler temperatures will kill off the plant. If you choose to sow seed in September, ensure that your climate conditions are favorable for both germination and mature flowers.

Climate

• In many regions of North America, the first frost date occurs during the months of October and November. If you choose to transplant fully grown marigolds into your garden during the month of September, you can reasonably expect to enjoy your flowers for up to 2 months before they succumb to winter's chill. In warmer parts of the country, however, September-planted marigolds can persist for as long as temperatures remain above 60 degrees Fahrenheit. Be aware, however, that marigolds, like all plants, have a life cycle. Once the flowers fade and the seeds have dropped, your annual plant will die, regardless of planting time and climate.

Indoor Growing

• Greenhouse production creates a steady supply of both African and French marigolds throughout the year. These plants are sold commercially though nurseries and garden centers. Amateur and home gardeners are able to grow marigolds indoors as well. Sow seeds in a moist growing medium -- preferably one with a coarse texture. The seedlings will germinate at the same rate as they would when sown outdoors under similar temperature and moisture conditions. The seedlings are ready to transplant within 3 weeks of germination. Transfer them to larger pots at this time. French marigolds flower up to 14 days before African varieties begin to bloom. Marigolds are capable of being grown indoors at any time of year.