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:
• Store seeds in the refrigerator (not freezer) until ready to sow.
• Do not store at room temperature for extended periods, as seeds lose viability quickly outside of cool conditions.
• Before sowing, soak the seeds in room temperature water for 24 hours to rehydrate and soften the seed coat.
When to Sow:
• Spring is best for stored seed, particularly in cooler climates.
• Sow once the risk of frost has passed and soil temperatures are consistently above 65°F (18°C).
Sowing Instructions:
• Sow in deep trays (minimum 10 cm) using a mix of 50% river sand + 50% fine compost.
• Sow thinly, as seedlings will remain in trays for their first year.
• Lightly press seeds into the surface and barely cover with a thin layer of soil or vermiculite—they need light to germinate.
• Keep the medium moist but not soggy and place in semi-shade or under grow lights.
• Germination takes 30 to 120 days (4 to 17 weeks), sometimes longer under suboptimal conditions.
Light Requirements:
• Seeds require light to germinate. Use Full-spectrum LED or fluorescent grow light for 12–16 hours/day if sowing indoors.
• Keep lights 10–15 cm (4–6 inches) above the soil surface.
• Temperature: Maintain 21–28°C (70–82°F)
• 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.
• Maintain bright, indirect light for young seedlings.
• Mature plants thrive in full sun to partial shade.
Soil Requirements:
• Prefers well-draining, sandy or loamy soil, enriched with organic matter.
• Ideal pH: 6.0–7.5.
Watering:
• Keep soil evenly moist during germination.
• After germination, allow the topsoil to dry slightly between waterings.
Spacing & Transplanting:
• Year 1: Leave seedlings in trays.
• Year 2: Transplant into individual pots.
• Year 3: Move to final location—garden beds or containers—spaced 12–18 inches (30–45 cm) apart.
Growing Tips:
• Flowering begins in the third or fourth year from seed.
• Known for stunning flower umbels on tall stalks.
• Excellent for containers, borders, and Mediterranean-style gardens.
• Hardy in USDA Zones 8–11—in colder zones, overwinter indoors.
? More information: https://pza.sanbi.org/agapanthus-praecox