Coleus, made popular as Victorian-era bedding plants, have made a huge comeback thanks to the all-season color the lovely foliage offers, whether it's planted in full sun or shade. Coleus plants are characterized by square stems and leaves situated directly opposite one another. Though it produces tiny blue to white flowers, they are insignificant and are often pinched off to conserve the plant's energy. The foliage can vary widely in shape, style, and color. Breeders regularly produce new introductions with even more unusual colors and patterns.
Soil
Coleus prefers consistently moist, rich, well-draining soil. Before planting, amend the soil with compost or another organic material. For potted plants, any good-quality potting mix will work fine. Make sure to choose a container with drainage holes.
Container-grown coleus loves the loose texture of potting soil, and it always helps to start with a quality mix with a slightly acidic to neutral pH of 6.0 to 7.0. Provide drainage in the pot to ensure the soil isn't constantly wet, which can lead to root rot.
Water
Coleus plants grow best in soil that is consistently moist but not soggy. The soil should not remain wet all the time, but long dry spells will slow the plants’ growth, and the leaves will start to turn brown around the edges. Let the soil dry out a bit between waterings, and water when the top inch of soil feels dry to the touch.
Indoor plants need water only when the top inch of soil feels dry to the touch.
Temperature and Humidity
As a tropical plant, coleus thrives in hot, humid conditions. In temperate climates, the barest hint of frost will spell the end of the plants. Move plants indoors or protect them on chilly nights when temperatures dip into the 50s. If growing outside, make sure to take cuttings for propagation before the weather turns cold.
Keep indoor plants away from air conditioner vents and other cold spots. In dry climates, the plants will like some humidity from a humidifier or a bathroom environment. To take potted plants outdoors in spring, wait until the temperature is 70 degrees Fahrenheit or warmer.
Fertilizer
Feed container-grown plants once a month with a water-soluble fertilizer. Container plants generally need more feeding than garden plants because frequent watering washes nutrients from the potting soil.
