Place the container with the French marigolds in an area with full sun at least six to eight hours a day. This keeps the marigolds blooming all season
Water the marigolds whenever the container’s soil dries out to about 1 inch deep. Add enough water to the soil that it runs out of the container’s bottom.
Fertilizer potted French marigolds once every two weeks with an annual flower fertilizer. Sprinkle 1 tablespoon of the water-soluble fertilizer into the watering can and fill the can with water. Pour the water over the marigolds until water drains out of the container’s bottom.
Pinching off the dead flowerheads when they occur keeps the plant blooming all season.