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.
COLD STRATIFICATION (before sowing):
- Moisten a paper towel or small amount of vermiculite/perlite—just damp, not soaked.
- Place the seeds on the damp medium and fold gently.
- Insert into a labeled, resealable plastic bag or airtight container.
- Store in the refrigerator (not freezer) at 4–5°C (39–41°F) for 2–4 weeks.
- Check weekly: If seedlings sprout in the fridge, remove them gently and plant immediately.
- After stratification, remove seeds and sow immediately.
When to Sow
- Indoors: Start 6–8 weeks before the last frost.
- Outdoors (spring-summer): Sow in late spring to early summer after stratification, once the soil has warmed.
- Outdoors (fall): In mild climates, seeds can also be sown directly in fall. Cold winter conditions act as natural stratification and encourage spring germination. Choose a well-drained spot and avoid waterlogged soil.
- If winters are harsh (deep freezes with little snow cover), consider mulching lightly or opting for late winter or early spring sowing instead.
Soil & Location
- Prefers well-drained, alkaline to neutral soil (pH 6.5–7.5).
- Amend heavy soils with grit or coarse sand to improve drainage.
- Needs full sun for the best flowering display.
Sowing Instructions
- Do not cover seeds—light is essential for germination.
- Requires 12–16 hours of light per day (use grow lights)
- Press seeds gently onto the surface of moist soil.
- Spacing: Thin or transplant seedlings 15–30 cm (6–12 in) apart.
Watering & Germination
- Keep soil moist but not soggy.
- Use a fine mist spray to avoid washing seeds away.
- 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.
- Germination time: 14–28 days at 18–21°C (65–70°F) AFTER stratification.
Transplanting & Care
- Move seedlings outdoors after the last frost once hardened off.
- Water sparingly—Aubrieta becomes drought-tolerant once mature.
Trim lightly after flowering to keep the plant compact and vigorous.