How to Raise Marigolds

Start marigold seeds indoors about six weeks before the last frost. Fill a container with regular potting soil. Bury the seeds about 1/2 inch deep and water the soil to settle it and to moisten the seeds.

Cover the container with a plastic bag so the air stays humid and the soil stays moist until the seeds sprout. Keep the seeds in a warm and sunny spot that stays between 65 and 75 degrees Fahrenheit. Remove the plastic when they are about 1 inch tall and thin to one plant for every 2 inches.

Plant the seedlings outside after the soil has warmed to about 70 degrees in a spot where they will receive full sunlight. Although marigolds prefer dry, warm days, they need the rich, loamy soil usually found in a garden plot.

Keep the soil damp until the seedlings are large enough to reach water lower in the soil, or about the first three weeks after planting.

Weed around the plants to keep competing plants from robbing the soil nutrients or blocking the sunlight.

Mulch around the base of the plant with a mulch that contains nitrogen, such as grass clippings or shredded root. This conserves water in the soil for the hotter weeks of summer.

Deadhead the flowers by pinching them off once they start to wither and die, saving a few seedheads for the following year. This will keep the plant producing new blossoms throughout the summer.

Fertilize marigolds with a balanced fertilizer once a week if they are not growing rapidly and producing flowers. Use a few inches of well-rotted compost to increase the quality of the soil under the flowers anytime during the summer, unless you have applied decorative mulch.