Buzz
Coleus, also referred to as painted nettle, flame nettle, or painted leaf, is grown for its beautifully patterned foliage. The leaves of the coleus plant display a vibrant array of colors, including white, yellow, red, pink, purple, dark brown, copper, and various shades of green. Coleus adds a striking visual appeal both indoors and outdoors, though in tropical climates, it’s advisable to bring the plant inside during winter.
Steps
Growing Coleus from Seeds
Prepare seeds in early spring. For optimal results, start growing the plant indoors about 8–10 weeks before the last frost is expected in your area. If planting out of season, you can sow the seeds in late spring or summer, but the plants may not grow as vigorously or healthily.
Prepare small pots with loose soil. Place seed trays or small pots indoors and fill them with loose potting soil or indoor plant mix. Coleus thrives in well-draining, loose soil, so consider adding peat moss or a similar material to loosen the soil if it’s too compact.
Sow the seeds on the soil surface. Spread the seeds evenly over the soil and cover them with a thin layer of soil, about 3 mm deep. Avoid burying the seeds too deeply, as they require light to germinate.
Keep the soil moist. Water lightly but regularly to maintain soil moisture without waterlogging. If the environment is dry, cover the tray or pot with plastic wrap to prevent the soil from drying out.
- Remove the plastic wrap as soon as the seeds sprout.
Keep the seeds in a warm area with indirect light. Maintain the seed tray at a temperature of 21°C in a spot with indirect sunlight.
Transplant the seedlings into larger pots. Remove the plastic wrap once the seeds sprout. When the seedlings develop small cotyledons and two true leaves, they can be safely transplanted into larger pots or directly into the ground. Refer to the care instructions below to continue growing your coleus plant.
Growing Coleus from Cuttings
Take cuttings from a mature plant or purchase them. To take coleus cuttings, select a stem without flowers or buds at the tip. Cut just below a leaf node, ensuring the cutting is about 10–15 cm long. Cuttings can also be purchased directly, often with small root balls already developing.
- You can take cuttings of 5–8 cm from smaller coleus plants.
Remove the leaves. Depending on the length of the cutting, one or two leaf nodes—areas where leaves grow from the stem—should be planted underground. Trim off the leaves from the lowest nodes to prevent them from rotting when buried.
Dip the lower end of the cutting in rooting hormone (optional). Coleus typically roots quickly on its own, but store-bought rooting hormone can speed up the process. If using this method, follow the instructions on the label to prepare the hormone solution, then dip the lower end of the cutting into it.
Grow in water (optional). Most coleus cuttings thrive in a glass of water. Change the water daily, place the cutting in indirect light, and transplant it into soil once roots develop. The soil method described below can also be used for further growth.
Plant the cuttings in moist soil. Place each cutting in a small indoor pot. Use nutrient-rich, well-draining soil and moisten it before planting. If the soil is too compact to insert the cutting directly, use a pencil to create a hole, then place the cutting inside. Ensure the leafless end of the cutting is buried in the soil.
Cover the newly planted cuttings with a plastic bag. Since the cuttings lack roots, they cannot replenish water lost through their leaves and stems. To prevent this, cover the entire pot and coleus plant with a plastic bag to retain humidity. Use sticks or straws to keep the plastic from touching the cuttings directly.
- Remove the bag once new growth appears, typically after 1–4 weeks.
Keep the room warm and avoid direct sunlight. Maintain the pot in a room with a minimum temperature of 21°C. Provide plenty of indirect light. Once the plant develops roots and leaves, follow the care instructions below. You can keep the plant indoors or move it outdoors if you live in a warm climate.
- Cuttings bought from nurseries are often grown in greenhouses and may not be accustomed to direct sunlight. Gradually acclimate them by moving the pot from shaded areas to sunnier spots.
Caring for Coleus Plants
Move the coleus plant outdoors. To transplant the plant outside, choose a well-draining garden spot with full sun or partial shade. Dig a hole twice the size of the root ball and plant it at the same depth as it was in the pot. Fill the hole with soil and add about 5 cm of compost around the root ball. Space coleus plants approximately half a meter apart.
Determine the amount of sunlight. The more sunlight coleus receives, the more vibrant its colors become. If possible, place your coleus in morning sun and afternoon shade. However, ensure the plant is in a shaded area during the hottest part of the day.
- If your coleus is losing leaves, it may need more sunlight.
- According to the USDA, the hardiness zones for coleus vary slightly by species, but most thrive in zones 9–10, especially if brought indoors during winter.
Keep the soil moist but not waterlogged. Coleus requires consistently moist soil but will suffer if left in standing water. In hot or windy conditions, water daily or even twice a day to maintain soil moisture. Increase watering if the pot dries out, the plant wilts, or its colors fade.
- Water directly at the soil level, as wet leaves can lead to disease.
Fertilize (optional). If you want faster growth, apply a moderate amount of 10-10-10 balanced fertilizer. Over-fertilizing can cause weak or uneven growth, so follow one of these methods to keep the plant healthy:
- Fertilize as directed on the label, only once per season.
- Or dilute the fertilizer to half or quarter strength and apply every two weeks.
Prune the coleus plant. Trim some branches to prevent the plant from becoming top-heavy and to maintain an attractive appearance. Here are common pruning techniques for coleus:
- To encourage upward growth, trim side branches but avoid cutting leaves growing from the main stem. This method creates a tree-like shape rather than a bushy one.
- Once the coleus reaches the desired height, prune the main stem tip to promote outward growth and a fuller appearance.
Remove flowers. Cut off flowers as soon as they appear to help the plant focus on developing strong roots and dense foliage rather than producing seeds. If you prefer flowers, remove most blooms and leave only a few in prominent locations.
Provide support for the plant if necessary. If the plant becomes top-heavy or leans to one side, gently tie it to a support stake using soft materials or ties. This method is particularly suitable for potted plants to minimize handling time.
- Prevent the plant from leaning by regularly rotating it towards the light source.
Protect Plants from Cold, Pests, and Diseases
Grow lemon balm indoors during cool weather. Bring the plant inside when frost is expected, as even a single frost can be fatal. Some lemon balm plants can tolerate nighttime temperatures consistently below 16°C. When grown indoors, keep the soil moist and stop fertilizing.
- Throughout winter, gradually increase shade for the plant until it is fully shaded. Sudden changes can cause leaf drop.
Eliminate mealybugs. Mealybugs are among the most common pests affecting lemon balm. They appear as white, cottony clusters on stems and leaves and can be wiped away with alcohol-soaked cotton swabs.
Control whitefly infestations. Whiteflies appear as swarms of tiny white insects and/or clusters of white eggs under leaves. For outdoor plants, purchase ladybugs or Encarsia parasitic wasps to combat whiteflies. For indoor plants, use sticky traps or homemade traps to catch them.
Dealing with other pests. For most insects, such as aphids, you can spray them with water or wipe them off with a cloth. Some pests require specific methods to eliminate:
- "Spider mites" can be deterred by increasing humidity. Place a water tray nearby and cover the affected area.
- Tiny black spots hovering over the soil are "fungus gnats," which can be managed by adding a 6 mm layer of gravel on the soil surface or reducing watering and improving ventilation.
- Deter slugs by using a barrier of beer or copper, or purchase specialized slug control products.
Prune or treat diseased leaves. Circular spots with fuzz, black marks, or unusual shapes are often signs of fungal disease. Remove the affected leaves immediately, then sterilize your scissors or pruning tools with boiling water or rubbing alcohol to prevent spreading the disease.
- Fungicide sprays are available at garden supply stores if the infection continues to spread.
Tips
- If the frost has passed but you haven’t started growing lemon balm seedlings indoors, you can sow seeds directly in the garden. If doing so, transplant seedlings that grow too close together. You can plant them in pots 5 cm or wider.
- If you want to grow lemon balm with uniquely colored leaves, remove seedlings with ordinary green leaves. Wait until the true leaves (the second set of leaves) mature before making a decision.
