Aubrieta deltoidea, commonly known as Purple Rock Cress, is a low-growing mat-forming perennial from southeastern Europe that produces abundant lilac to purple flowers in spring. Seeds require light to germinate and benefit from a cool stratification period over winter to break dormancy. This species germinates readily within 10-30 days under proper light and moisture conditions, making it an excellent choice for spring-sown seed programs.
Before sowing
Sowing
What to expect
Tips
Surface sow seeds on soil without covering, as light is essential for germination. Water gently from below using a diffuser to prevent seed displacement. Maintain soil moisture consistently but avoid waterlogging. Ideal germination occurs at temperatures of 15-20°C (59-68°F). For indoor sowing, start seeds 6-8 weeks before the last frost date. After germination, provide bright indirect light. Once seedlings develop true leaves, acclimate them gradually to sunlight before transplanting. Space transplants 10-12 inches apart. Cold stratification over winter (30-90 days at 4°C) can enhance germination rates for outdoor spring sowing.
Sources: Gardeners HQ, Gardening Know How, Everwilde Seed, PFAF Plant Database, Royal Botanic Gardens Kew, Wikipedia
