Marigolds are popular annual flowering plants that bloom in bright shades of yellow, orange and red. Generally used in borders and beds, marigolds add a colorful accent to hanging baskets as well. Marigolds enjoy warm temperatures and lots of sunshine. Start the seeds six to eight weeks prior to the last frost in your area.
Fill a seed flat with equal parts of potting soil and peat moss. Run room-temperature water over the mixture until it drains from the bottom of the flat. Allow the flat to sit until the water has completely drained.
Sprinkle the marigold seeds across the surface of the soil and cover with 1/4 inch of perlite. Use the misting bottle to lightly mist the top layer of soil until it is moist.
Place the seed flat on a heat mat set to 75 to 80 degrees F. Marigold seeds do not require light to germinate so place the flat in any convenient area. Use the misting bottle to keep the soil moist. The seeds should germinate within two weeks.
Reduce the heat mat temperature at night, when the seedlings first appear, to 70 degrees F, turning it back to the original temperature during the day.
Fertilize the marigold seedlings when they have their second set of leaves with a 15-0-15 diluted to one-quarter of the strength recommended on the package.
Remove the seed flat from the heat mat when the marigolds reach 2 inches in height.
Transplant the seedlings into a sunny location in the garden after all danger of frost has passed.