How Long After Sowing Seeds Will a Sunflower Bloom?

Growth Rate

• Sunflower growth rates vary based on the variety and where they are planted, but most have relatively short growing periods. They usually go from seed to maturity within 90 to 100 days. In Missouri, for example, sunflowers planted in early June will be in bloom by early August. Sunflowers display rapid early growth that slows down significantly once they reach their full height.

Germination

• In the vegetative stages, sunflower seeds emerge from the soil and develop their true leaves. Seeds usually germinate within five days if the ground is warm and they are lightly covered with soil. Seeds that are buried too deeply or planted in cool soil conditions will not germinate as quickly. Ideal soil temperatures are 46 to 50 degrees F.

Problems

• Watch both seedlings and established plants for signs of disease. Sunflowers are most commonly affected by fungi, including sclerotinia stalk and head rot, downy mildew, rust, verticillium wilt, phoma black stem, leaf spot and powdery mildew. Common pests include several types of sunflower moth, beetles, midge and maggots.