How Will Temperature Affect the Height of Marigolds?

Seed Starting

• Marigolds are warm weather plants, and the seeds will germinate in 3 to 5 days when the temperature is 75 to 80 degrees F. The soil, or germination medium, should be kept moist during initial germination. Once the marigold seedlings begin to emerge, reduce the moisture level and the temperature to 69 to 70 degrees F. As your marigold seedlings begin to approach transplant size, the temperature should be lowered to 60 to 65 degrees F.

Temperature

• In full sun, with higher temperatures than plants growing in partial shade, marigolds will flower profusely and grow to maximum height. The combination of light intensity and temperature will influence a marigold's development, growth and quality. When your marigold plants grow in high temperatures but low light levels, the plants will grow rapidly and high but will have weak stems, small flowers and limited foliage. For strong, lush foliage and abundant marigold flowers, grow them in full sunlight.

Care

• As seedlings or budding marigold plants grow, they will mature quicker when temperatures are 80 degrees F or higher. Marigold plants grown in daytime temperatures closer to 60 degrees F will take twice as long to reach maturity. Overnight temperatures should not drop below 60 degrees F for your marigold plants to thrive and reach maximum height. Deadhead spent flowers on your marigolds to increase flower budding and abundant blooms.

Uses

• For hot, dry areas of your landscape, marigold plants will grow fast with few problems. With a wide variety of marigolds to choose from, a gardener can grow the plant in containers or as a bedding plant, enjoying the colorful flowers throughout the growing season. Marigold flowers can also be used as long-lasting cut flowers. Dwarf varieties to tall -- up to 36 inches -- can be grown throughout your flower and vegetable gardens.