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: Cold stratify seeds in a moist paper towel inside a plastic bag in the refrigerator for 21–30 days.
Step 2: After stratification, lightly press seeds into the soil surface.
When to Sow
Indoors: Start seeds 6–8 weeks (42–56 days) before your last expected frost.
Outdoors: For natural stratification, sow seeds outdoors in late fall (after the first few frosts) so they experience winter chill. Scatter seeds on the soil surface and gently press them in — do not cover. Germination will occur in spring as temperatures warm.
How to Sow Indoors
Use a seed-starting mix in trays or pots. Press seeds into the surface—do not cover, as light is required to germinate.
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: 14–28 days after stratification
Post-Germination Care
Once seedlings have true leaves, transplant into individual pots if needed. Harden off before planting outdoors. Final spacing: 30 cm (12 in) apart.
Type: Short-lived perennial often grown as an annual
Mature height: 45–60 cm (18–24 in)
Prefers full sun and well-draining soil. Tolerates drought once established. Deadhead to extend blooming.