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.
Keep soil evenly moist during germination. DO NOT LET IT DRY OUT—once seeds begin absorbing water (imbibition), drying can kill the seed embryo, and even brief dryness after sprouting can kill seedlings.
Seed Treatment
Cold Stratification: Place seeds in a moist paper towel inside a sealed bag and refrigerate at 35–40°F (1–4°C) for 7–10 days.
Check regularly: If seedlings sprout in the fridge, remove them gently and plant immediately.
When to Sow
- Indoors: Start 6–8 weeks before your last expected frost.
- Outdoors: Direct sow in early spring once the danger of frost has passed, or in late fall to allow natural stratification.
Sowing Depth
- Surface sow — seeds need light to germinate.
- Use a folded paper to sow evenly or press gently into the soil without covering.
- Use grow lights to maintain 12–16 hours of light per day.
- Maintain steady temperatures of 60–70°F (16–21°C). Use a heat mat if necessary.
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.
Watering
- Keep soil consistently moist until seeds sprout.
- Once seedlings are established, water at the base.
Germination: up to 28 days AFTER stratification
Spacing: Thin or transplant seedlings 6–9 inches (15–23 cm) apart.
Growing Tips
- Produces charming, snapdragon-like flowers in a range of bright colors.
- Prefers well-draining soil, even poor or sandy types.
- Avoid overly rich soil, which can reduce flowering.
- Ideal pH: 6.0–7.5
- Best in full sun (6+ hours daily).
- Tolerates light shade but may flower less abundantly.
- Blooms from late spring through summer, especially if deadheaded regularly.
- May self-seed lightly in favorable conditions.
- Best grown as a cool-season annual in most climates.
More guides at: bloomoutlet.com/seed-guides