The coleus, also known by the term "painted nettle", is cultivated for the spectacularity of the leaves that grow with showy colors, such as white, yellow, red, pink, purple, brown, copper and a wide range of greens. This plant adds an interesting touch to the interior, but also to the exterior, although, with the exception of tropical climates, it is necessary to keep it indoors during the winter.
Steps
Part 1 of 4: Planting the Seeds
Step 1. Germinate the seeds in the spring
For best results, you need to plant the seeds indoors 8-10 weeks before the last frost is expected in your region. If needed, they can also be started in late spring or summer, but be aware that this way they cannot grow very quickly or healthily.
Step 2. Prepare small containers with fertile, loose soil
Arrange a seed tray or small pots indoors and fill them with potting soil. Coleus thrives in rich, well-draining soil, so mix in some peat or other similar material if the soil is particularly dense.
Step 3. Sprinkle the seeds in the soil
Distribute them in the potting soil by covering them with a light layer (3 mm) of the same. Don't bury them too much, as they need light to germinate.
Step 4. Keep the soil moist
Water the seeds lightly, but often, so the earth stays consistently moist without getting too soggy. If the seedlings are in a dry environment, cover the trays or jars with cling film to prevent them from drying out.
- To water the seedlings in a small pot, soak the pot with water. The water will gradually move into the land. This method is less aggressive with seedlings.
- When the seedlings begin to sprout, remove the plastic wrap.
Step 5. Keep the seeds warm, in indirect sunlight
Make sure that the trays are exposed to a constant temperature of about 21 ° C and leave them in a bright area, but not in direct sunlight.
Step 6. Transplant the new seedlings into a larger container
Remove the plastic wrap, if any, as soon as you see the seedlings begin to sprout. When the first, small "leaf" and two pairs of adult leaves appear on the plant, it is time to safely transfer it to your pot or directly to the garden. Follow the instructions in the section of this article that deals with caring for an adult coleus plant.
Part 2 of 4: Growing Coleus from Cuttings
Step 1. Take cuttings from adult plants or buy them
If you want to grow a coleus from a cutting, choose a branch that has neither a flower nor a bud at the tip. Cut it directly under a leaf knot, so that the cutting is 10-15 cm long. Eventually, you can also buy it directly in a nursery or garden center; those available on the market, usually, have already developed a small root ball.
If you want, you can also take cuttings of about 5-7.5 cm from smaller coleus varieties
Step 2. Remove the leaves
Depending on the length of the cut, the presence of one or two leaves, or the area where the leaves grow from the stem, the cuttings should be planted at a certain depth below the soil surface. Cut the leaves that grow from these lower nodes, otherwise they rot under the soil.
Step 3. Dip the cut end into rooting hormone (optional)
Coleus usually develops roots quickly on its own, but if you want to speed up their development, you can use a rooting hormone, which is easily found in garden stores or nurseries. If you decide for this solution, follow the instructions on the package to prepare the product, then briefly dip the end of the cutting into it.
Step 4. Grow the cutting in water (optional)
Almost all coleus cuttings grow easily with this technique as well. Make sure you change the water daily, keep the plant in a bright, indirect sunlight, and transplant it into a pot when you notice the roots starting to grow. In any case, the soil cultivation method, explained below, also works just as well.
Step 5. Plant the cuttings in moist soil
Insert each individual cut into its own little pot indoors. Use a rich, well-draining soil and wet it a little before placing the seedling. If the soil is not sufficiently loose to be able to insert the branch directly, use a pencil to create the hole and facilitate entry. Plant the coleus so that the leafless nodes are under the soil.
Step 6. Cover the young cuttings with a plastic bag
Since they have not yet developed the roots, they are not yet able to compensate for the hydration they lose from the leaves and stem. To counteract this phenomenon, completely cover the pot and the coleus cut with a plastic bag, to retain the humidity in the air. Use sticks or toothpicks to keep the bag from touching the cutting directly.
Remove the bag when you notice new growth on the cutting, usually after 1-4 weeks
Step 7. Keep the seedling in a warm room in indirect sun
Place the pot in a room with a constant temperature of at least 21 ° C, leave it exposed to a lot of sunlight, but indirect. Once the plant has developed roots and leaves, you can continue caring for them by following the directions in the next section of this tutorial. You can decide to keep the plant indoors or move it to the garden if you live in a warm climate.
Cuttings purchased in nurseries are almost always grown in greenhouses and are not used to full sun. If you decide to place them outdoors, transfer them gradually, moving the pot from an area in full shade to others that are more sunny
Part 3 of 4: Caring for the Coleus
Step 1. Transplant the coleus outside
To move the plant outside, choose an area of your garden where the water drains properly, in the sun or partially in the shade. Dig a trench twice as large as the original root ball and plant the coleus at the same depth as the pot. Replace the soil around the plant. You may also want to sprinkle some mulch all around. Space the plants about 12 inches apart if you have more than one.
Step 2. Determine how much you want to expose it to sunlight
Know that the more sun it receives, the more vivid its colors will be. If you can, make sure you keep the coleus in the sun throughout the morning and in the shade in the afternoon. Otherwise, keep the plant in partial shade constantly.
- If you notice that it sheds its leaves, it probably needs more sun.
- You can grow coleus in areas with different climatic conditions, but it generally thrives best in those regions where minimum temperatures never drop, on average, below -5 ° C, as long as it is kept indoors in winter.
Step 3. Keep the soil moist, but don't soak it too much
This plant needs constant moist soil, but it rots if it remains soaked with water. If the climate is particularly hot or windy, it may be necessary to water it every day or even twice a day, to keep the soil at the right degree of humidity. Increase the amount of water if you notice signs of withering, dry brown spots or if the color fades.
Water the soil directly because, if they get wet, the leaves become vulnerable to disease
Step 4. Fertilize (optional)
If you want to accelerate the growth of the plant, you can use a universal fertilizer, such as a 10-10-10 solution. Fertilizer may promote wild or weak growth, so do one of the following to make sure you apply the right amount:
- Apply a slow-release fertilizer and follow the instructions on the package, but only once per growing season.
- Or make a mixture diluted with 50% or 25% liquid fertilizer and apply it once every 2 weeks.
Step 5. Prune the coleus
It is a good idea to cut off some branches of the plant to prevent it from becoming too heavy on the tips and to give it a graceful shape. Here are the basic pruning techniques used most often for this plant:
- To encourage coleus to grow tall, cut the side branches slightly, but not the leaves that grow directly from the trunk. Follow this procedure if you want the plant to take on a more "tree" appearance instead of a large bush.
- Once the coleus has reached the desired height, snap the upper central shoot of the plant with your fingers to stimulate it to spread out and thicken.
Step 6. Break the flowers
Pinch the tips of the flowers as soon as they appear, so the plant focuses its energy on growing strong roots and thick canopy, rather than creating seeds. If you like flowers, try to remove most of them and leave only the most visible ones.
Step 7. Support the plant if necessary
If you see that it gets heavy on top or tends to bend in one direction, gently tie it to a garden stake with twine or other soft material. It would be best to do this during the repotting process to minimize the number of times the plant is stressed.
Eventually, you can prevent the indoor plant from bending by turning it regularly so that all sides are exposed to sunlight
Part 4 of 4: Protecting the Coleus from Cold, Pests and Diseases
Step 1. Keep coleus indoors in cold weather
If your plant is outdoors, move it indoors whenever there is a danger of frost, since even a single, light frost is often enough to kill it. Some varieties of this plant can suffer even when the temperature at night regularly drops below 16 ° C. When keeping it indoors, make sure it is away from drafts and stop any form of fertilizing.
- During the winter, gradually expose it to more and more shade until it is completely in full shade. Sudden changes can cause leaves to drop.
- When you bring the plants indoors they will lose a few leaves. This happens because they adapt to the new conditions. Keep an eye on their humidity, temperature and sun exposure during the first few weeks.
Step 2. Kill the mealybugs
These are among the most common parasites that can infest coleus. They usually appear as clumps of white fluff on the stem or leaves and can be wiped off with an alcohol-soaked cotton swab.
Step 3. Watch out for a possible whitefly infestation.
These pests appear as clouds of small white insects and / or many white eggs on the underside of the leaves. If the plant is outdoors, get ladybugs or Encarsia formosa bugs to kill these pests. If the plant is houseplant, hang some traps for whiteflies that you find on the market or build them yourself.
Step 4. Deal with any other infestations
Most other insects, such as aphids, can be eliminated by simply spraying water or wiping the plant with a cloth. If you want to get rid of certain types of parasites, however, sometimes it is necessary to use more specific techniques.
- The small red "spider mites" can be removed by increasing the humidity. Place a container of water nearby and lightly mist the entire infested area.
- If you see small black dots fluttering near the ground, know that these are "mushroom flies", which can be treated by adding 6 mm of gravel on top of the soil or by reducing irrigation and increasing air circulation.
- Get rid of snails by placing a beer or copper barrier or purchasing a specific product to eliminate them.
Step 5. Prune or treat diseased leaves
If you notice black, fuzzy patches, ring-shaped spots or other abnormalities, they are usually the result of fungal diseases. In this case, immediately cut the affected leaves and then sterilize the scissors or shears with boiling water or alcohol to avoid spreading the disease to other plants.
You can find anti-fungal sprays at garden stores if the disease continues to spread
Advice
- If the danger of frost has passed, but you have not started the seedlings indoors, you can spread the seeds directly in the garden. If you follow this method, transfer any seedlings that grow too close together. You can plant each plant in a pot with a diameter of 5 cm or larger.
- If you are growing coleus for its original colorful leaves, weed out those seedlings that grow with common green leaves. Wait, though, until the true adult leaves have grown (the second set of leaves) before making a decision.
