Marigolds are popular garden plants because they come in a wide range of color combinations and sizes, and they grow quickly and easily. You can also grow marigolds indoors as house plants.
Marigold varieties can range from 6 inches to 4 feet in height, and 6 inches to 3 feet in width. For indoor growing, you should choose a smaller variety such as dwarf French marigolds, which are smaller than 12 inches fully grown.
You can plant marigold seeds in shallow seed trays to begin with, and move the plants to pots or planters once they've begun to grow. Or you can plant the seeds directly in the pot you'd like to display the plant in. Seeds should be placed 1/8 inch to1/4 inch deep in good potting soil, and kept moist in a warm, sunny spot.
Indoor marigolds will grow best in a sunny, south-facing window. If you don't have a window that receives full sun, marigolds will also respond well to a grow light.
While many people consider marigolds a warm-weather plant, marigolds can be grown indoors year-round. Their bright flowers make them a good choice for an indoor winter flower garden.
Marigolds do have a strong odor that some people find objectionable, so keep this in mind if you'll be growing the plants in a small space. There are a few odorless varieties of marigolds, but seeds can be difficult to find.