Starting Coleus Indoors: A Colorful Winter Project

January's gray skies cry out for color, and coleus seedlings deliver it in abundance. Native to tropical regions of Asia, Africa, and Australia, these tender perennials (grown as annuals in temperate zones) bring a tropical vibe indoors when outdoor gardens sleep. Start seeds 10 weeks before your last frost date for spring transplants, or anytime for houseplants.

Growing from Seed

Coleus seeds germinate in 10–12 days in vermiculite or fine potting mix. Sow in a covered flat or low tray (any light-transmitting cover works) to retain moisture—don't seal tightly, or damping-off may occur. Keep warm, out of direct sun. In northern climates, January light is insufficient; fluorescent or LED grow lights are essential for strong, colorful seedlings. Once true leaves appear, transplant to individual pots.

Propagating from Cuttings

To preserve a favorite cultivar, take softwood stem cuttings just below a leaf node. Remove lower leaves, dip in rooting hormone, and place in sterile potting mix or moist sand. Water rooting also works: set stems in a vase of room-temperature water, changing it until roots form. Pot up rooted cuttings for garden transplanting in spring.

Quick Facts

• Scientific name: Solenostemon scutellarioides (formerly Coleus hybridus, C. blumei)
• Family: Lamiaceae (mint family)
• Zones: All as annual; perennial in tropics
• Light: Shade to full sun (red-leaved varieties tolerate more sun)
• Moisture: Ample; avoid waterlogging
• Pests: Aphids, mealybugs, whiteflies; stem/root rot if overwatered

Cultivar Highlights

Over 500 cultivars exist. A sampling:

Sun-loving: 'Alabama Sunset' (brick red), 'Blair's Witch' (burgundy/purple with yellow-green edges), 'Pineapple' (lime green with burgundy stems), 'Plum Parfait' (ruffled plum with pink borders), 'Solar Storm' (deeply sculpted red, green, off-white).

Partial shade: 'Dark Star' (near-black), 'Purple Emperor' (royal purple, ruffled), 'India Falls' (amethyst mounds, carpet type), 'Sunset' (jeweled garnet), 'Thumbelina' (compact green/burgundy).

Tips for Success

• Victorians adored coleus as "jewels of the garden."
• As plants age, they become leggy and colors fade—propagate fresh cuttings regularly.
• Bring indoors before frost for winter color.
• Full sun dulls some varieties; red-pigmented leaves handle sun best.