Mrs. Steen/ Mrs. Detert
Biology/ English 10
Coleus and Terrariums
Coleus is a very beautiful plant that consists of over 150 different species. It is best known for its colorful foliage. Coleus can grow well in any soil above 55 degrees Fahrenheit. The pretty plant can grow in terrariums. Terrariums are gardens under glass which means that they are jars or glass boxes that can be filled with soil and other things that plants need to grow. They dont have to be watered so once they are finished, all there is to do is to sit and look at the plant. Will coleus grow faster in a large, small, or medium sized terrarium?
Coleus plants are durable and easy to grow. They are best known for their bright colors and variety of foliage forms. Although they are technically a tender perennial (even the slightest frost will cause them to die), they are most often considered to be an annual plant by growers and seed producers. Coleus plants may be grown in the garden in bright, indirect light, or in partial shade. The lower growing dwarf varieties (six to twelve inches) will create a colorful border, or the taller (three foot) types can be used as a dramatic background plant. Most coleus plants will survive full sun exposure. The foliage color, however, is often enhanced when they are grown in shade. Coleuses are also quite striking when they are planted in a container and grown as a houseplant. By removing the flower spikes as they develop and keeping the plant pinched back, the coleus can be kept in a perennial state for several seasons. Although these plants are members of the nettle family, they are a mint. They do not have the stinging properties of the nettle.
A coleus makes a nice houseplant as long as it receives sufficient light and food. The coleus should be planted in a light, quick draining planting soil. It should be placed where it will receive several hours of bright light (south window) each day, or provide artificial grow lighting for best leaf color, and fullest plant. Coleus plants will adapt to a wide range of temperatures above 55 degrees, but will grow best when they are kept between 70 and 85 degrees. The soil should be kept evenly moist, but never soggy. The coleus plants should be fed monthly with a diluted (50% mix) liquid houseplant fertilizer. Flower buds must be pinched off as soon as they develop to prevent the plant from producing seeds. (The flower spikes are very insignificant.) Once a coleus is allowed to go to seed, it has completed its life objective, and it will usually die. Pinching may also be necessary to prevent leggy growth. Any time that the tip growth is removed, the plants energy will be diverted to the lateral side growth, creating a much bushier plant. Coleus are very durable, so it can be cut back severely if needed (almost back to the soil level). (Coleus, Illustrated Encyclopedic, 75)
Coleus plants should not be set into the landscape until the minimum outdoor temperature is 50 degrees F. Although coleus plants will usually survive in full sun, the foliage color tends to intensify in light shade when they are grown outdoors. They should be planted twelve inches apart in rich, moist, well drained soil with a neutral or slightly alkaline pH. It should be fed monthly with a liquid all purpose (10-10-10) fertilizer. The center stem should be pinched out when the plants are four to six inches tall to induce bushier growth, and the flower spikes should be picked as they form as they form. If the soil is allowed to dry out, the foliage will wilt, but normally will recover quickly when additional water is provided. The plants should be watered thoroughly at planting time, and then the entire bed should be mulched to conserve moisture. The mulch will also help to heat up and retain the heat in the soil, thereby helping the plants to get established in their new home. (Coleus, Academic, 105)
Expanding any persons coleus collection is quite easy. Seeds are inexpensive, readily available, and can be sprouted and showing their first colors in as little as two weeks. Another advantage to growing coleus this way is that each packet of seeds will contain many different colors of plants. From this, preferred varieties can be chosen for cloning for the future by taking cuttings. If the intent is to grow the coleus as a houseplant, the seed may be sown indoors at any time of the year. If the seedlings are destined for a garden location, they should be started indoors at least ten weeks before the last expected frost so that the plants will be well developed when it is time to plant them outdoors. Coleus seeds are very small. They should be sown onto a layer of moistened, sterile potting soil in a shallow tray and then covered with a thin layer of fine soil. The tray should be covered with a pane of glass or sheet of plastic to retain moisture until the seeds have sprouted. The tray should be kept in a warm (65-75 degree F.), bright (NOT full sun) place. When the seedlings are large enough to handle easily, they should be thinned out and transplanted into individual pots. (Seedlings should always be held by a leaf, never by the stem!) When all danger of frost is past, the plants may be set out in the garden. Propagating the coleus by cuttings is equally as easy. Taking softwood stem cuttings at any time of the year can clone a coleus plant. A sharp, clean knife should be used to cut the stem just below a leaf node. The lowest leaves should be removed and then the cut end should be dipped into a rooting hormone and insert it into some fresh, sterile potting soil. These cuttings will be ready to use as a bright garden accent by early June. They will also root quickly when set in moist sand or vermiculate or even in a glass of room temperature tap water. (Coleus, New Encyclopedia, 231)
Cuttings should be taken in the fall, prior to a killing frost, and the coleus should be grown as a houseplant to brighten the winter months. (Coleus, Encyclopedia, 450) In February or March, again take several cuttings and cultivate them for transplant into a garden when the weather warm. Propagation by cuttings will do a lot toward renewing older plants, but the cloned baby will quickly become the better plant. (Herwig, Coleus, 110)
Terrariums are miniature gardens enclosed in glass or clear plastic. Any type of houseplant can be grown in a terrarium arrangement. The humid microclimate inside the container is the ideal solution to dry, centrally heated rooms which can be harmful to plant health. The one exception to this is the family of cacti and succulents, which are prone to rot in humid environments. These are better kept in open dishes. Terrariums require a minimum of care if they are kept sealed. The moisture that plants absorb from the soil is given off through the leaves by the process of transpiration. This condenses on the glass walls and runs down to moisten the soil again. The atmosphere also remains balanced through the combined plant processes of photosynthesis and respiration. A well-constructed terrarium requires only light and warmth to flourish. (Terrarium, World Book, 176)
Any clear or tinted glass or plastic container can be used if it will admit light and allow plants to be seen. Fish tanks, brandy snifters, pickle jars, and casserole dishes all make attractive displays. If they do no come equipped with a lid, a sheet of clear plastic or glass makes a suitable cover. Small openings on the top of the container are acceptable, but there may be a need for water from time to time. The container must be clean. Bacteria, fungi, and algae thrive on soiled surfaces in warm, moist environments. (Terrarium, Illustrated Encyclopedic, 520)
Most plants recommended for terrarium and bottle gardens are moisture-loving types which never become large. Because most houseplants are of tropical or subtropical origin, they thrive in the terrarium environment. Apart from cacti and succulents, the selection is nearly unlimited. Plants with similar requirements for temperature, light, and water, should be chosen. For example, mosses and ferns, which thrive in poorly lit areas, are incompatible with coleus or crotons which need strong light to remain healthy. Miniature flowering plants fit particularly well into terrarium arrangements, including miniature African violets, roses, and geraniums. For a woodland effect, mosses, lichens and small ferns can be gathered from a nearby forest and planted. Small stones, pinecones or bits of wood create a natural effect. Grass seed sprouts easily to make an attractive groundcover. (Terrarium, New Encyclopedia, 519)
When the terrarium or bottle garden is planted, they should be watered if necessary. Then it should be covered and placed in a shaded area until plants become re-established. They should be watched carefully for a few days. If water condenses on the glass inside the container, the lid should be removed for several days so excess moisture can evaporate. If plants wilt, and no condensation forms, add a small amount of water. After about one week, place the terrarium in a well-lit area, but never in direct sun. Glass seems to magnify the effect of the suns rays and temperatures within the terrarium build up to dangerous levels. Well-constructed terrariums do not need to be watered because plants recycle the moisture they use. Over-watering is the most common mistake made by terrarium owners. Of course, if there are openings in the top, watering will sometimes be necessary, usually not more than two to three tablespoons per month. Fertilizing is not recommended. Large, rapidly growing plants are undesirable in this case. You may need to prune certain plants when they become too large, or remove damaged or dead leaves occasionally. Otherwise, terrariums demand little attention and will grow successfully on their own for several years. (Terrarium, Encyclopedia, 518)
In conclusion, coleus is a very easy plant to grow, and a terrarium is a very easy way to grow plants. Coleus in a terrarium should turn out to be a very attractive experiment.