For optimal germination rates, initiate seed propagation indoors under controlled conditions—unless the species exhibits a high sensitivity to root disturbance. This approach allows precise regulation of temperature, humidity, and light, improving germination consistency and seedling viability. Do not skip any recommended seed treatments, as they are essential for uniform and successful germination.
Seed Treatment (Before Planting)
Step 1: Soak seeds in warm water for 12–24 hours.
Step 2: Cold stratify by placing soaked seeds in a moist paper towel inside a sealed plastic bag. Refrigerate for 10–14 days (10–14 days).
Check weekly—if seeds sprout in the fridge, plant them immediately.
When to Sow
Indoors: Start indoors 6–8 weeks (42–56 days) before the last expected frost.
Outdoors: For natural stratification, sow in late fall—seeds will overwinter and germinate in spring.
Light Requirements for Germination
Requires light to germinate. Do not cover seeds.
Use grow lights to maintain 12–16 hours of light per day.
Humidity
Use a humidity dome or clear cover to maintain consistent moisture during germination.
Open the dome briefly once per day to allow fresh air in and reduce mold risk.
Remove the dome entirely once seedlings emerge.
Optimum Germination Temperature: 18–22°C (64–72°F)
Germination Time:
Germinates in 14–45 days (after stratification) under ideal conditions.
How to Sow Indoors
- Press seeds gently onto moist seed-starting mix.
- Do not cover—light is essential.
- Keep soil surface moist, not soggy.
- Maintain warm temperatures and bright light throughout.
Post-Germination Care
- Transplant outdoors after last frost when seedlings are sturdy.
- Final spacing: 20–30 cm (8–12 in) apart.
- Type: Tender perennial (commonly grown as an annual).
- Mature height: 45–60 cm (18–24 in).
- Prefers full sun and well-drained, sandy or loamy soil.
- Water moderately; once established, plants are drought-tolerant.
Growing Tips
- Excellent for cut and dried arrangements—retains shape and color well.
- No need to deadhead, but pruning spent stems helps maintain shape.
- Avoid overly rich soil to prevent floppy growth.
- Can be grown in containers or open beds with good drainage.