Coleus: Sowing, planting and harvest calendar
How do you sow coleus indoors?
Start coleus indoors in a warm, bright place. For summer planting outdoors, sow several weeks before the expected planting date, following your packet’s timing. A roof or an unheated shelter alone does not provide the warmth these seeds need. For a houseplant, sowing can be done at other times if you can provide sufficient light and warmth.
Fill a clean seed tray or small pots with fine, free-draining seed compost. Moisten it before sowing and firm lightly. Scatter the tiny seeds thinly over the surface and press gently into contact with the compost. Do not bury them under an opaque layer: they need light to germinate. Label the variety and date.
Around 20–25°C is a useful starting range; follow the seed packet’s advice. Keep the surface evenly moist, using gentle misting or careful watering from below. Drain excess water. A transparent cover can reduce drying, but ventilate it and keep the tray out of scorching sun. Germination commonly takes a few weeks and varies with the seed lot.
Once seedlings emerge, remove the cover gradually and provide good light to prevent stretched stems. When true leaves have developed and the seedlings are manageable, separate them into small pots, handling a leaf rather than squeezing the stem. Acclimatise them gradually before outdoor planting in reliably warm, frost-free conditions. Keep young roots moist without waterlogging.
How do you plant coleus?
When does coleus flower?
