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
Soak seeds in warm water for 12–24 hours.
When to Sow
• Indoors: 56–70 days (8–10 weeks) before your last frost date.
• Outdoors: Direct sow after frost danger has passed, though indoor sowing is strongly preferred for uniform germination.
How to Sow Indoors
• Surface sow — press gently into soil without covering in a moist, well-draining seed mix.
• Cover very lightly with soil or fine vermiculite—do not bury.
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.
• Use grow lights to maintain 12–16 hours of light per day.
Germination
• Optimum Temperature: 20–22°C (68–72°F). Use a heat mat to maintain steady temperatures.
• Time to Germination: up to 35 days
Post-Germination Care
• Transplant seedlings carefully into individual pots once they have 2–3 true leaves.
• Harden off before planting outdoors.
• Final Spacing: 20–30 cm (8–12 in) apart.
• Type: Annual vine (tender perennial in frost-free zones).
• Mature Height: 1.8–3 m (6–11 ft) with support.
• Provide trellis, netting, or other support for climbing.
Growing Tips
• Prefers full sun but tolerates light shade.
• Thrives in rich, well-draining soil.
• Regular watering encourages continuous blooms.
• Pinching tips encourages bushier growth.
More guides at: bloomoutlet.com/seed-guides