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.
Keep soil evenly moist during germination. DO NOT LET IT DRY OUT—once seeds begin absorbing water (imbibition), drying can kill the seed embryo, and even brief dryness after sprouting can kill seedlings.
Seed Treatment
Soak seeds in warm water for 2-4 hours before planting.
When to Sow
Indoors: Start 10–12 weeks (70–84 days) before your last expected frost date.
Outdoors: Not recommended—requires warm, stable conditions to germinate.
Optimum Germination Temperature: Use a heat mat to maintain steady temperatures of 70–75°F (21–24°C)
Germination Time: Up to 28 days
Light Requirements for Germination
Light is required. Do not cover seeds with soil.
Use grow lights to maintain 12–16 hours of light per day.
How to Sow Indoors
- Use a sterile, well-draining seed-starting mix.
- Gently press seeds onto the surface—do not bury.
- Mist lightly with water to avoid seed displacement.
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.
Post-Germination Care
- Once seedlings have 2–3 true leaves, transplant into individual cells or pots.
- Harden off before transplanting outdoors after all danger of frost has passed.
- Final spacing: 8–12 inches (20–30 cm) apart.
- Type: Tender annual in most climates.
- Mature height: 10–16 inches (25–40 cm).
Growing Tips
- Prefers partial shade to filtered sunlight.
- Keep soil consistently moist but not soggy.
- Feed every 2–3 weeks with a balanced liquid fertilizer.
- Deadhead spent blooms to encourage continuous flowering.