The care information provided in this section represents the kind of practical advice is available for all the plants in this web site if you subscribe to the monthly customized newsletter Yardener’s Advisor.
Coleus is fairly easy to grow from seed, either indoors under lights or outdoors in the garden. If direct seeding is your choice for Coleus, sow seeds directly into the garden bed after all danger of spring frost is past.
Plant Coleus seedlings purchased at the garden center or nursery, or those you've started indoors, as soon as danger of frost is past and the soil is warm (when night time temperatures stay above 50 degrees). See Yardener’s Helper re: hardening off seedlings before planting outside. Space plants one to two feet apart depending on expected height of the variety you are planting.
If Coleus is growing in good soil containing lots of organic material, it wants only a light feeding in the spring when the seedlings are set out, about a half a tablespoon of slow-release granular fertilizer per plant. In poor soils use a bit more; one tablespoon of slow-release granular fertilizer per plant. That is all you need for the season. See Choosing Fertilizers in Yardener’s Tool Shed.
Optional task – Coleus grows best when mulched. As soon as the Coleus seedlings are tall enough, spread a 2 or 3 inch layer of some organic material such as chopped leaves, dried grass or wood chips on the soil around the plants. For more information see the file on Using Mulch
Coleus benefits from pinching off the flowers as soon as they appear to encourage more foliage. If the plants get leggy, pinching back the plant about one third of its height will improve the overall appearance of the plant.
Coleus, especially plants in containers, are vulnerable to drying out fairly quickly. In the heat of the summer keep the Coleus plants well watered during dry spells.
Coleus may be dug up and potted in late summer, then brought indoors for the winter as houseplants. Another way to keep plants is to take cuttings which root in water very easily. When the roots are well established transplant into a container with a good soilless mix. Keep Coleus in a window with good light and some sun. See Growing Plants In Containers and Containers For Plants in Yardener’s Tool Shed. Also see the Plant Propagation Equipment section of Yardener’s Tool Shed.
Your plants will die with the first hard frost. Remove them to the compost pile but keep the beds mulched right through the winter, ready for next year’s plants.
If you kept some Coleus over the winter as houseplants, in February or March you can take cuttings from those plants to produce more plants for spring planting outdoors. One trick is to give the plants a dose of liquid fertilizer which will cause it to produce sprouts that you can take for cuttings. See the Plant Propagation Equipment section of Yardener’s Tool Shed.