Most varieties bloom from early summer until hard frost in late fall. Marigolds require full sun and grow best in well-drained soil with plenty of organic matter. Prepare your flowerbeds by mixing in pine bark or leaf mold to 6 to 10 inches deep. Marigolds can be purchased as transplants or seeded directly in the garden. Start seed for transplants inside four to six weeks before planting out.
Most marigolds are hybrids.
If you save seed from last year's plants, they may not be the same as what you grew last year. Plant each plant slightly deeper than it was in the pack. Plant French marigolds 6 to 9 inches apart and African marigolds up to 18 inches apart. Keep a close check on water during the first 10 to 12 days. After that, water thoroughly once a week if it has not rained at least an inch that week.