Sunflowers are an iconic picture of summertime. You can find them short with small flowers, or over 10 feet tall with gigantic seed heads. No matter which type of sunflower suits your style, they all follow the same basic planting instructions. You can plant sunflower seeds directly into the ground, or start them indoors for an earlier bloom. Be aware that if you start the seeds indoors, sunflowers do not adapt well when transplanted. Using peat pots that are biodegradable, and can be planted directly into the soil with the seedling, is one way to minimize transplant shock.
Planting Directly Into Ground
Select a location for your sunflowers that receives full sun and has good drainage. Sunflowers are not picky about soil type, and will grow in anything from sandy soils to heavier clay soils. Plant sunflower seeds in spring, as soon as the soil can be worked, and after the danger of frost has passed.
Dig a shallow trench. If you soil is loose and sandy, dig it 2 inches deep. If it is hard and clay-like, dig it 1 inch deep. Once you have dug the trench, water it with 1 inch of water and let the water drain before putting the seeds down.
Insert the seeds into the soil, spacing them 12 inches apart, and cover with 1 to 2 inches of dirt. If you are planting giant sunflowers, they should be spaced 24 inches apart. Germination takes place within 10 to 14 days.
Starting Sunflowers Indoors
Purchase biodegradable peat pots that are at least 2 inches tall by 2 inches in diameter.
Place the peat pots in a leak-proof plant tray, and fill with a seed starter potting soil mix. Once the pots are filled, water them until they are moist, but not soaking wet.
Insert the sunflower seed 1 1/2 to 2 inches below the soil and then cover the pots with a sheet of plastic wrap. Place the pots in a warm, sunny window. Germination should take place within 7 to 10 days. Once the seedlings have developed two leaves, remove the plastic wrap.
Set the seedlings in a sunny area during the day, and then bring them in at night. Do this for a week before you plant them directly into the ground, as it helps them adapt to outdoor weather and temperatures.
When you plant them, plant the entire pot into the soil. Plant the pots just as you would a seed, but make your trench deep enough to cover the entire pot when you cover it. If you have a 2-inch pot, you should work a trench that is 3 inches deep. When you plant pots, water them from above ground after you have planted them. You may need to water them with 2 inches of water, every other day, until the sunflowers get rooted in the soil, which may be up to 10 days.