Seed Treatment
Soak seeds in lukewarm water for 2–4 hours before sowing.
Do not cover seeds with soil—light is needed to germinate.
Best Time to Sow
Indoors: Start seeds indoors 8–10 weeks before your last frost date.
Outdoors: Sow outdoors only after all danger of frost has passed and nighttime temps stay above 60°F (16°C).
Germination Conditions
Temperature: 70–75°F (21–24°C)
Light Requirement: 12–16 hours of bright light daily – use grow lights if sowing indoors.
Germination Time: up to 21 days
How to Sow
- Press seeds gently onto moist seed-starting mix; do not cover with soil.
- Mist the surface and cover tray with plastic wrap or a humidity dome.
- Keep in a warm, well-lit area with consistent humidity.
Watering
Keep soil consistently moist, not soggy. Mist to avoid washing away tiny seeds.
Post-Germination Care
- Remove humidity dome once seedlings emerge.
- Provide bright light or grow lights for 14–16 hrs/day to prevent leggy growth.
- Transplant when seedlings have 2–3 true leaves.
- Harden off before moving outdoors by gradually exposing to outdoor conditions.
Growing Tips
- Pinch tips regularly to encourage bushier growth.
- Coleus is frost-sensitive: bring indoors or overwinter as a houseplant in cold climates.
- Ideal as a border plant, container filler, or indoor color accent.
USDA Zones: Annual in zones 2–9, perennial in frost-free zones 10–11
Height: 12–36 in (30–90 cm) depending on variety
Light Needs: Partial shade to full shade outdoors; bright indirect light indoors