Sunflower Soil Needs

Soil

• The crop adapts to a wide variety of soil types including sand and clay but perform best in sandy loam. Though the plant has a lower requirement for soil macronutrients as compared to potato, wheat or corn, medium to high levels of macronutrients are required for good growth. A well-drained ground is important for plant health. Sunflower is poorly tolerant of soil salt and moderately tolerant of flooding. Adequate levels of soil moisture are critical for healthy seed germination.

Seeding Time

• There is a great variation of possible planting dates for the crop especially in regions with long growing seasons. Using quick-maturing cultivars allows for multiple planting in the same year. In other geographical locations of the world that barely experience winters, sunflowers are harvested throughout the year. Plant in early spring in the northern areas of the United States, preferably between May 1 and 20. In the southern regions, plant between the middle of March and early April. Avoid planting near frost dates in the north as seedlings are sensitive to frost, especially in the six-leaf stage.

Weed Management

• Control weeds early and regularly to reduce competition with crop for light, nutrients and water. Though sunflower resists weeds well, unkempt weeds are likely to reduce yields. Common weeds that require early control include both annual and perennial weeds. Use cultural and chemical control options. More than two-thirds of sunflower cultivation in the United States are treated with herbicides for weed management.

Disease

• Sunflowers are prone to a number of often potentially dangerous diseases. Even though new cultivars have considerably higher resistance to disease, the damage is rapid once an infection occurs. Diseases that can seriously reduce yields include verticillium wilt and sclerotinia stalk/head rot. Less serious but still frequent fungal disorders include downy mildew, rust and phoma. Disease management starts with early identification of symptoms and timely application of curative fungicides.