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 in warm water for 8 hours before sowing.
When to Sow Indoors
Start seeds indoors 42–56 days (6–8 weeks) before your last expected frost.
When to Sow Outdoors
Direct sowing is not recommended, as seedlings are frost-sensitive and germinate less reliably outdoors.
How to Sow Indoors
- Fill trays or pots with a fine, well-draining seed mix.
- Surface sow the seeds; press gently into the soil but do not cover. Seeds need light to germinate.
- Mist to settle seeds.
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. - Use grow lights to maintain 12–16 hours of light per day.
Optimum Germination Temperature: Use a heating mat to maintain steady temperatures of 20–24 °C (68–75 °F).
Germination Time: up to 28 days.
Post-Germination Care
- Transplanting: Move seedlings into individual pots once they have 2–3 sets of true leaves.
- Spacing: Plant outdoors 25–30 cm (10–12 in) apart after frost risk has passed.
- Type: Tender perennial, usually grown as an annual in temperate climates.
- Mature height: 45–75 cm (18–30 in).
- Prefers full sun and well-draining soil.
- Pinch back tips to encourage branching and more blooms.
Growing Tips
- Avoid overwatering—allow the top of the soil to dry slightly between waterings once plants are established.
- Deadhead faded flower spikes to extend blooming season.
- Attracts pollinators such as bees and butterflies.
More guides at: bloomoutlet.com/seed-guides