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 (Before Planting)
Cold Stratification: Mix seeds with moist sand or a damp paper towel, seal in a plastic bag, and refrigerate at 40°F (4°C) for 4–6 weeks.
Check weekly to ensure moisture is maintained — not soggy — and if seedlings sprout in the fridge, remove them gently and plant immediately.
Sowing Instructions
When to Sow:
Start in spring or early summer, after the last frost.
Soil:
Use a rich, sterile, well-draining mix — peat moss, perlite, and compost are ideal. pH 5.5–6.5.
Light:
Use grow lights to maintain 12–16 hours of light per day.
Sowing Depth:
Surface sow — press seeds gently into the soil without burying.
Optional: Dust with a light layer of vermiculite or fine sand.
Spacing:
Space plants 12–24 inches (30–60 cm) apart for good airflow and bushy growth.
Watering:
Keep soil moist but not soggy. Mist gently to avoid shifting 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.
Germination Temperature: Use a heat mat to maintain a steady temperature of 68–75°F (20–24°C)
Germination Time: 1 to 3 months — sometimes longer, so stay patient!
Aftercare
Thinning/Transplanting: Once seedlings have a few sets of true leaves, transplant to larger pots or their outdoor location.
Fertilizer: Use a diluted liquid feed every 2–3 weeks to support healthy growth.
Mulching: Apply light mulch to conserve moisture.
Pruning: Pinch back tips to encourage fuller, bushier plants.
Hardening Off: Once seedlings are over 6 inches tall, gradually introduce them to outdoor conditions before planting permanently.
With a bit of patience, you’ll enjoy stunning red and white blooms that attract hummingbirds and brighten any shaded garden space!