Spring Planting

• Since sunflowers don't need a cold season to germinate, you can pop them right into the ground as soon as the winter ends. Wait until the ground thaws and threat of frost is over, usually around the end of April or early May in temperate climates. In milder climates, you can plant as early as the end of March. Sunflowers planted before the last frost are at risk of dying in the ground or freezing to death after sprouting. Young sunflowers are delicate and require warm soils and air temperatures to grow and flower.
  
  

Winter Starting

• Starting sunflowers indoors gives you hardier plants to put into the ground when spring arrives. For temperate climates with harsh winters, start the seeds in seed flats in early March. The sunflowers will grow to about a foot before the weather permits you to plant them in the ground. Place your flats under grow lights or in a sunny window on a seed flat heat mat. This ensures the sunflowers remain warm and get all the light they need.
  
  

Planting Location

• Choose a location for your sunflowers that remains in full sun for the entire day. The south side of your home or the inside of the north side of a fence works well because the structures act as a wind break. Young sunflowers may succumb to inclement weather and high winds if you plant them out in the open. Choose an area with moist, well-drained soil that is dark in color. Sunflowers can grow in a variety of conditions, but these are ideal. Waterlogged sunflowers or plants in poor soil will not grow to their full height or produce viable seeds.
  
  

Planting Method

• Push sunflower seeds into warm, prepared soil about 2 feet apart in parallel rows about 2 feet apart. Dwarf varieties, like the teddy bear sunflower, can grow as close as 1 foot from each other.
  
  Water the soil until it's moist but not muddy; about ½ cup per seed works well. Water seed flats this way every three days. Water in-ground seeds every other day; the sun will evaporate a lot of the water. Your sunflowers should spring up in about two weeks. Don't worry if you see an aphid infestation on them. They can't harm the seeds or the flowers.