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
Cold Stratification Required:
• Mix seeds with moist sand or peat
• Seal in a plastic bag and refrigerate for 4–6 weeks at 35–40 °F (1–4 °C)
• Check weekly: If seedlings sprout in the fridge, remove them gently and plant immediately.
• Check periodically to keep medium moist (not wet or moldy)
Best Time to Sow
• Outdoors: Late fall (natural stratification) or early spring after cold treatment
• Indoors: Start 6–8 weeks before last frost after stratifying
Optimum Temperature
• 15–20 °C (59–68 °F) for best germination
How to Sow
• Surface sow – press seeds into soil, do not cover (light needed)
• Use grow lights to maintain 12–16 hours of light per day.
• Mist soil gently to avoid displacing 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.
Watering
• Keep soil evenly moist during germination
• Avoid soggy conditions
Germination Time
• Typically in 3–6 weeks after stratification under ideal conditions
Spacing
• Thin or transplant seedlings 6–12 in (15–30 cm) apart
Growing Tips
• Full sun to partial shade
• Well-draining, loamy or sandy soil
• pH 6.0–7.5 (neutral to slightly acidic)
• Forms graceful clumps – ideal for borders, wildflower areas & rock gardens
• Low-maintenance and drought-tolerant once mature
• Attracts pollinators with star-shaped blue-purple blooms
More guides at: bloomoutlet.com/seed-guides