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
Step 1. Scarification: Gently rub seeds with sandpaper or nick them with a sharp knife to help water penetrate the seed coat.
Step 2. Soaking: Soak seeds in lukewarm water for 12 hours before planting.
Step 3. Cold Stratification: Place seeds in a moist paper towel inside a sealed plastic bag and refrigerate for 2–3 weeks (14–21 days) before planting.
Check weekly: If seedlings sprout in the fridge, remove them gently and plant immediately.
When to Sow
Indoors: Start indoors 6–8 weeks (42–56 days) before your last expected frost date.
Outdoors: Can be direct sown in fall or early spring in mild climates where natural stratification can occur.
Germination Temperature: Optimum: 20–22°C (68–72°F)
Germination Time: 10–30 days (after stratification) under ideal conditions
Light Requirements for Germination
Use grow lights to maintain 12–16 hours of light per day.
How to Sow Indoors
Sow seeds on the surface or lightly cover with a thin layer of soil or fine vermiculite (1–2 mm). Use seed-starting mix in pots or trays. Maintain even moisture without saturating.
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.