Grow Coleus

Coleus, also commonly known as painted nettle, flame nettle, and painted leaf, is grown for its ornate foliage. The leaves of these plants grow in eye-catching colors including white, yellow, red, pink, purple, maroon, copper, and a wide range of greens. Coleus makes an attractive addition indoors or outdoors, although outside of tropical climates you will need to bring any coleus indoors once the temperature drops below below 50º F (10º C).

Steps

Growing Coleus from Seeds

  1. Start the seeds in early spring. For best results, plant the seeds indoors, 8–10 weeks before the last frost is expected in your area.[1] In a pinch, seeds can be started in late spring or summer, but may not grow as quickly or healthily.[2]
  2. Prepare small containers of loose, rich potting soil. Keep a seed tray or small pots indoors, and fill them with seed starting soil or potting soil. Coleus thrives in rich, well-draining material, so mix in peat moss or a similar, loose gardening medium if the soil is dense.
  3. Sprinkle seeds over the soil. Spread the seeds onto the soil. Cover them with a thin, ⅛ inch (3 millimeter) layer of the same soil.[3] Do not bury them in the soil, as they require light to germinate.
  4. Keep the soil moist. Water the seeds lightly but frequently, so the soil remains moist without becoming soggy.[3] If the plants are kept in an arid environment, cover the trays or pots with plastic wrap to prevent them drying out.[4]
    • To water seedlings in small pots, soak the pot in water. The water will work its way up into the soil. This is less disruptive to the young plants.
    • Remove the plastic wrap as soon as you see seedlings emerge.
  5. Keep the seeds in warm, indirect sunlight. Keep the seed trays at 70º Fahrenheit (21.1º Celsius) at all times, in an area of bright, indirect sunlight.[4][3]
  6. Transplant to a larger container. Remove the plastic wrap, if present, as soon as the seedlings emerge. After a seedling has grown its first, small "seed leaf" and two sets of adult leaves, it can be safely transplanted to its own pot, or directly into the soil.[4] Refer to the instructions in the care section below to continue handling your coleus plant.

Growing Coleus from Cuttings

  1. Take cuttings from adult plants, or purchase them. To take a coleus cutting, choose a branch without a bloom or bud at the tip. Cut directly below a leaf node, so the cutting is 4–6 in. (10–15 cm) long.[4] Cuttings are also available for purchase directly, and typically come with a small root ball already developed.
    • You may take cuttings 2–3 in. (5–7.5 cm) from smaller coleus species.[5]
  2. Remove the leaves. Depending on the length of your cutting, one or two leaf nodes, or areas on the stem where leaves grow from, will be planted beneath the soil. Cut off the leaves growing from these lowest nodes, or they will rot when buried.
  3. Dip the cut end in rooting hormone (optional). Coleus usually roots quickly on its own, but rooting hormones from a gardening supply stores can be used to speed up their development. If you decide to go this route, follow the instructions on the label to prepare the hormone solution, then dip the cut end of the cutting into it briefly.
  4. Grow them in water (optional). Most coleus cuttings will grow in a glass of water. Change the water every other day, keep the plant in bright, indirect sunlight, and transplant the coleus to a pot once you notice root growth.[4] The soil method below works just as well.
  5. Plant the cuttings in moist soil. Plant each cutting in its own, small, indoor pot. Use a rich, well-draining potting soil, and moisten it before planting. If the soil is not loose enough to push the cutting into directly, use a pencil to create a hole for it.[4] Plant the coleus so the bare leaf nodes are under the soil.
  6. Cover young cuttings with a plastic bag. Because young cuttings have not yet grown roots, they are unable to make up for the water they lose from their leaves and stem. To counteract this, cover the entire pot and coleus cutting with a large plastic bag, to trap moisture in the air. Use sticks or toothpicks to prevent the plastic bag from touching the cutting directly.
    • Remove the bag once you notice new growth on the coleus, typically after 1–4 weeks.
  7. Keep in a warm room with indirect sun. Keep your potted coleus in a room with temperatures at least 70ºF (21ºC) at all times. Expose it to plenty of indirect sunlight. Once the plant has developed roots and foliage, you can continue caring for it using the instructions below. You may keep it as an indoor plant, or transfer it to your garden if you live in a hot climate.
    • Cuttings purchased from a nursery are typically greenhouse-raised, and not used to full sun. Transfer them outside gradually, moving the pot from areas of heavy shade to sunnier areas.[5]

Caring for Coleus

  1. Transplant the coleus outside. To move the plant outside, choose an area in your garden that drains well with full sun or partial shade. Dig a hole that is twice the size of your root ball, and plant it at the same depth that it was planted in the pot. Replace the soil around the plant. You may want to spread an inch or two of mulch around the plant. Coleus plants can be planted about one foot apart from each other.
  2. Decide on a sunlight level. The more sun coleus receives, the more vibrant its colors will be. If possible, expose your coleus to sun all morning and shade in the afternoon. Otherwise, keep your coleus in partial shade.[3]
    • If your coleus is dropping leaves, it probably needs more sun.
    • USDA Hardiness zones vary slightly by species and variety, but most coleus plants thrive in zones 9–10, if they are kept indoors in winter and outdoors the rest of the year.[6]
  3. Keep the soil moist, but not soggy. Coleus plants require constant moist soil, but will rot if left in puddles. In very hot or windy conditions, you may need to water daily or even twice daily to keep the soil moist. Increase the amount of watering if you notice wilting, dry brown spots, or fading color.[5]
    • Water the soil directly, since wet leaves are vulnerable to disease.
  4. Fertilize (optional). If you want to speed up the plant's growth, use a general purpose fertilizer such as a 10-10-10 solution. Fertilizer can promote straggly or weak growth, so use one of the following options to keep it to beneficial levels:
    • Apply a timed-release fertilizer according to instructions, just once each growing season.[5]
    • Or dilute a liquid fertilizer to ½ or ¼ strength, and apply once every 2 weeks.[3]
  5. Prune the coleus. Removing some of the plant's branches is recommended to prevent the coleus becoming top-heavy, and in order to shape it attractively. Here are the basic pruning strategies commonly used for coleus:
    • To encourage coleus to grow straight, pinch off the side branches, but not the leaves growing directly on the stem. Do this if you want a more "treelike" appearance, instead of a wide bush.[7]
    • Once the coleus has reached the desired height, pinch off the top center shoot on the plant, to encourage it to fill out and become bushy.[2]
  6. Pinch off flowers. Remove flowers from the plants as soon as they appear, so the plant focuses on growing strong roots and thick foliage instead of creating seeds.[5] If you enjoy the flowers, consider removing most of them and leaving the ones in the most visible locations.
  7. Stake the plant if necessary. If the plant becomes top-heavy or leans in one direction, tie it loosely to a gardening stake using twine or another soft material. Ideally, do this during repotting to minimize the number of times you handle the plant.[7]
    • You can also prevent indoor plants from leaning by regularly adjusting which side of the plant is exposed to the light.[8]

Protecting Coleus from Cold, Pests, and Disease

  1. Keep coleus indoor in cool weather. Bring outdoor coleus plants inside whenever there is a risk of frost, as a single light frost is often enough to kill the plant.[3] Some coleus plants may even suffer if night temperature are regularly below 60ºF (16ºC).[5] While indoors, keep the plant away from drafts, and stop fertilizing the plant.
    • During winter, gradually increase the amount of shade the coleus receives, until it is in full shade. Sudden changes can cause leaf drop.[9]
    • When you bring the plants inside, they will drop a few leaves. This is because they are adapting to the new conditions. For the first few weeks, carefully monitor their moisture, temperature, and sunlight exposure.
  2. Kill mealy bugs. Mealy bugs are one of the most common pests found on coleus. These appear as tufts of white fuzz on the stem and leaves, and can be wiped off with a cotton swab dipped in alcohol.[5]
  3. Control-Whiteflies. Whitefly infestations show up as clouds of small white insects, and/or many white eggs on the undersides of leaves. For outdoor plants, purchase ladybugs or Encarsia species to kill the whiteflies. for indoor plants, hang up whitefly traps or Control-Whiteflies.
  4. Deal with other pests. Most other insects, such as aphids, can be sprayed off with water or wiped off with a cloth. Some pests require more specialized methods of control:[5]
    • Tiny red "spider mites" can be driven away by increasing the humidity. Place pans of water nearby and mist the affected area lightly.
    • Tiny black dots hovering near the soil are "fungus gnats," which can be dealt with by adding ¼ in (6 mm) fine gravel on top of the soil, or by reducing watering and increasing air flow.
    • Get-Rid-of-Garden-Slugs by using a barrier of beer or diatomaceous earth, or purchasing a specialized slug control product.
  5. Prune or treat diseased leaves. Fuzz, black or ringed spots, or other disfigurements are usually the result of fungal disease. Cut off affected leaves immediately, then sterilize the scissors or shears with boiling water or rubbing alcohol to avoid spreading the disease to other plants.[5]
    • Anti-fungal sprays are available at garden supply stores if the disease continues to spread.

Tips

  • If the danger of frost has passed but you did not start coleus seedlings indoors, you can sprinkle seeds directly into your garden. If you go this route, transplant any desirable seedlings that grow too close together. You can place each plant into a pot that is 2 inches (5 cm) or larger.
  • If you are growing coleus for its unusual, colorful foliage, weed out seedlings that grow ordinary green leaves. Wait until the true, adult leaves grow (the second set of leaves) before making your decision.
  • When the plants reach six inches tall, clip off the top bud to encourage the plant to grow more bushy foliage.

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