How To Grow Sunflowers From Seeds Indoors. When the growing season is long, wait until the soil temperature in the pot reaches 55 to 60 degrees f. Try to plant the seeds as soon as possible.
Sunflowers properly grow best in the locations with full sun. Sow two seeds per pot, cover with plastic to keep moist; In sandy soil, 2 inches deep is better.
Push the seed 1.5cm into the compost and water in.
Push the seed 1.5cm into the compost and water in. Place the sunflower seeds on one half of the towel, then fold it over to cover them. Sow one seed per 7.5cm pot. If growing sunflowers from seed indoors ahead of time, use peat pots, which are ideal for plants like sunflowers that don’t like to be transplanted.