Marigolds are a very versatile flower. They enjoy full sun and hot days and grow well in dry or moist soil. This hardiness is one of the reasons that they are often used as bedding plants and container plants. Once marigold flowers are planted, they need little care. If they are plannted in the ground, you only need to water them if the weather has been very dry for more than two weeks. If they are in containers, water them daily as containers will dry out quickly. Water-soluble fertilizer can be given to them once a month, but to be honest, they will do as well without fertilizing as they do with it. You can greatly increase the number of blooms and the blooming time length by deadheading spent blossoms. Dried, spent blossoms can also be kept in a cool, dry place, and the seeds inside these flower heads can be used to grow next year's display of fiery orange, red, and yellow marigold flowers.