Agastache rugosa (Korean Mint)

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 24 hours before sowing.

When to Sow

Indoors: Start 30–45 days (4–6 weeks) before your last frost date.
Outdoors (natural stratification): Surface sow in late fall; seeds will germinate in spring.

?️ Germination Conditions

  • Optimum temperature: Use a heat mat to maintain steady temperatures of 20–25 °C (68–77 °F)

  • Germination time: up to 28 days

  • Light requirement: Seeds need light to germinate. Surface sow—do not cover with soil.

  • Use grow lights to maintain 12–16 hours of light per day.

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.

How to Sow Indoors

  1. Fill trays or pots with a well-draining seed-starting mix.

  2. Surface sow seeds and gently press them into the soil. Do not cover.

  3. Mist lightly with water to avoid displacing seeds.

  4. Place under grow lights and maintain consistent moisture and warmth.

Post-Germination Care

  • Transplanting: Move seedlings outdoors after frost danger has passed. Harden off gradually.

  • Spacing: 30–45 cm (12–18 in) apart.

  • Type: Perennial herb, aromatic, pollinator-friendly.

  • Mature height: 60–120 cm (24–48 in).

  • Soil: Well-draining, moderately fertile soil.

  • Light: Full sun for best flowering.

  • Watering: Drought tolerant once established; avoid waterlogging.

Growing Tips

  • Pinch back young plants to encourage bushier growth.

  • Deadhead spent blooms to prolong flowering.

  • Attracts bees, butterflies, and hummingbirds.

Excellent for borders, herb gardens, and pollinator habitats.

? More guides at: bloomoutlet.com/seed-guides

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