Italian White Sunflower Seeds

Sow Helianthus Debilis seeds straight into the garden after your last frost, once the soil reaches at least 60°F. Plant each Italian White Sunflower seed half an inch deep and space them 12 to 18 inches apart to ensure every plant has enough space for branching, or 8 inches apart if you want tighter, smaller blooms for cut-flower work. Italian White Sunflower seeds germinate in 7 to 10 days at 70 to 75°F. You can start indoors White Sunflower seeds for planting in biodegradable pots 3 to 4 weeks before the last frost, but we don’t recommend it, as plants grow weakly and bloom count significantly drops.

White Sunflower plants need full sun, at least 6 hours a day, to produce strong stems and a proper bloom. They handle a wide range of soils, but they perform best in well-drained loam with moderate fertility and a pH between 6.0 and 7.5. Water plants deeply once or twice a week depending on heat. Once established they tolerate dry stretches, so you may reduce watering frequency.

Pinch out the central growing tip when plants reach 18 to 24 inches if you want a bushier shape with more flowers. Feed White Sunflower seeds with compost or a balanced fertilizer once at planting and again at first bud, and skip anything high in nitrogen, which only pushes leafy growth and delays blooming. For cut flowers, harvest in the early morning when one or two outer petal rows have opened, strip the lower leaves and drop the stems straight into cool water. Italian Sunflowers live in a vase for 7-10 days if you change the water every two days and recut the stems each time.