When to Plant Sunflowers in Sacramento

Site and Soil

• Sunflower seeds and plants require six to eight hours of sun every day, so choose the sunniest site in the yard in which to plant the seeds. Remove weeds and other vegetation to reduce competition for soil nutrients and moisture. Add ½ cup of starter fertilizer, such as 8-24-6, for each 100 square feet of planting area. Scratch the fertilizer into the top 6 inches of soil to get the seeds off to a healthy start.

Planting

• Wait until the soil temperature is at least 50 degrees Fahrenheit to plant. Water the soil to a depth of 6 inches, allow it to drain until it’s moist and not saturated, then plant the sunflower seed 1 inch deep and 6 inches apart. If you’re growing particularly tall varieties, space them 1 foot apart; giant sunflowers should be planted 2 feet apart. The seeds will germinate within five days in warm soil. Give them an extra few days if the soil is cool.

Care

• Sunflower seeds need lots of moisture to germinate and until they are established. Don’t allow the soil to become swampy, but ensure that it is evenly moist at all times. Once the plant is 4 to 6 inches in height, start allowing the top inch or two of soil to dry out before watering again. Fertilize the sunflower with 1/3 cup of 32-0-0 mid-season, applied as a side dressing. Dig a 2-inch-deep trench alongside the row of sunflowers, but 5 inches away. Sprinkle the fertilizer into the trench and cover with soil and water to a depth of 4 inches.

Harvest

• Harvesting sunflowers for their seeds is one of the best features of growing them. The birds will try to beat you to the seeds, so protect the flower heads by covering them with hole-studded paper bags, tied lightly to the stem with string. Check the flowers periodically and cut them from the plant when the seeds are gray or they have black stripes and the disk at the back of the flower turns brown. Rub the seeds out with your hands or remove them by rubbing two sunflower heads together.