Seed Treatment
Step 1: Scarification
Lightly nick the seed coat with a nail file or sharp blade or soak in warm (not boiling) water for 12–24 hours to soften the seed coat.
Step 2: Cold Stratification
Wrap soaked seeds in a moist paper towel, seal in a plastic bag, and refrigerate for 14 days. Check weekly—if seeds sprout, plant them right away.
When to Sow
Indoors: Start 28–42 days before the last expected frost
Outdoors: Sow in early spring or late fall for natural stratification
Optimum Germination Temperature: 15–21°C (60–70°F)
Germination Time: 14–42 days after stratification
Light Requirements: Not light-dependent for germination. If growing indoors in low light, use grow lights to maintain 12–16 hours of light per day.
How to Sow Indoors
- Sow seeds 0.6–1.2 cm (¼–½ inch) deep in well-draining seed-starting mix
- Keep soil evenly moist, not soggy
- Final spacing: 30–45 cm (12–18 inches) between plants
- Indoor Tip: Lupines dislike root disturbance—start in deep biodegradable pots or root trainers to transplant with minimal disruption
Humidity
Use a humidity dome or clear cover to maintain consistent moisture. Open the dome briefly once per day to allow airflow and reduce mold. Remove the dome entirely once seedlings appear.
Post-Germination Care
Type: Perennial
Mature Height: 60–120 cm (2–4 ft)
Sunlight: Full sun to partial shade
Soil: Well-drained, slightly acidic to neutral
Watering: Moderate—water regularly until established
Fertilizer: Not necessary; lupines fix nitrogen naturally
Staking: Helpful in windy areas
Deadheading: Encourages longer blooming and reduces reseeding
Transplanting Tip: Handle seedlings gently and avoid disturbing roots