Description
The sunflower (Helianthus annuus) is a vibrant and cheerful flower known for its striking golden-yellow petals and large, sunny center. It is primarily cultivated worldwide for oil extraction. Sunflowers can be grown from seeds and are available in various colors and sizes, typically reaching heights of about 6 feet, although some varieties can grow anywhere from 2 to 15 feet tall. Their impressive stature and bright appearance make them a popular choice for gardens, adding warmth and joy to any landscape.
Planting requirements
Planting season: March to April and End of October to early November
Planting conditions:
| Propagation | Seeds |
|---|---|
| Planting method | Plant seeds 1 to 2 inches deep. Space smaller varieties 6 inches apart and taller varieties 12 inches apart. Thin seedlings as they grow, and keep rows 2 to 3 feet apart |
| Soil | Sunflowers can grow in sandy soils and hard soils with moderate clay content but are unsuitable for acidic soils with poor drainage for commercial cultivation |
| Water | Adequate soil moisture is crucial during the flowering period (7-8 weeks after emergence), so weekly supplemental irrigation is recommended to support rapid growth |
| Light | Full sunshine (at least 6 hours of direct sunlight) |
Growing conditions:
| Temperatures | Moderate temperatures are preferred during seed germination and early growth, while hot conditions are essential during flowering and maturation |
|---|---|
| Soil | Well-drained, fertile soil is essential. Sunflowers prefer sandy loam with a pH between 6.5 and 7.5. If soil pH is too low, lime can be added to improve it. The soil should also retain moisture without becoming waterlogged |
| Water | Adequate soil moisture is critical during the flowering period (7-8 weeks after emergence), requiring weekly supplemental irrigation due to rapid growth |
| Pruning | Not Applicable |
| Weed Control | Apply plenty of mulch to supress weeds |
Harvesting
Can be harvested within 10-11 weeks. Once the flowers mature, petals will shed and the head becomes brownish color. Harvest individual flowers using a knife.
Curing
After harvesting, allow the seeds to dry in the sun for about 2-3 days. Then peel off the seeds from the head and sundry the seeds to reduce the moisture content up to 10%.
Storage
Store dried seeds in an airtight container in a cool, dark place. Stored properly, sunflower seeds can last up to a year.
Protecting your plants
Pest control
Pest type:
- Leaf-footed bugs
- Stink Bugs
- Caterpillars
- Aphids
- Birds
Symptoms:
- Leaf-footed bugs: Damage to plant stems, leaves, and flowers.
- Stink Bugs: Severe damage to plants and crops due to piercing and sucking mouthparts.
- Caterpillars: Devoured leaves and flower petals.
- Aphids: Feeding on plant sap, found on most plants in gardens.
- Birds: Eating of sunflower seeds.
Control method:
- Spray neem oil
- Apply insecticides if needed but be cautious.
- For birds: Use spinners, scarecrows, or owl decoys.
Disease Control
Disease type:
- Alternaria leaf spot
- Phoma leaf spot
- Rhizopus head rot
- Rust
- White mold
- Powdery mildew
- Downy mildew
Symptoms:
- These diseases can cause both yield and quality reduction of sunflowers.
- Powdery mildew and downy mildew appear at later growth stages.
Management:
- Practice crop rotation
- Deep plow crop residue
- Ensure proper spacing
- Cultural practices can often reduce disease severity without the need for fungicide spray
- In severe cases, fungicide application may be necessary
