Introduction to Houseplant
Houseplant, a potted plant that is easily grown indoors. Houseplants provide decoration for the home and a hobby for the indoor gardener. Many varieties of foliage (leafy) plants, flowering plants, and succulent plants are suitable as houseplants.
Some of the many popular foliage plants grown for their attractive and often unusual leaves are palms, the rubber plant, the Chinese evergreen, the fiddle-leaf fig, ivies, and philodendrons. Many foliage plants, such as the dracaenas, dieffenbachias, and calatheas, have variegated (patterned) leaves. Among those whose leaves are splashed with color are caladiums, coleus, and crotons.
African violets, azaleas, gloxinias, geraniums, begonias, cyclamens, and the shrimp plant are flowering plants popular for their colorful seasonal or year-round blossoms. The group of houseplants known as succulents includes the aloes, crassulas, echeverias, houseleek, sedums, and the many species of thorny and spiny cacti. Succulents are grown most often as ornamental curiosities because of their unusual forms and their thick, odd-shaped, fleshy leaves or stems. Many succulents also bear blossoms.
Unlike plants grown outdoors, house-plants must be provided with all of their basic needs—light, appropriate temperature, humidity, water, soil, and food. It is important that the indoor gardener acquire certain simple skills—a knowledge of methods of potting, propagation, and pruning.
Basic Needs of Houseplants
LightAll houseplants need a certain amount of light each day for growth, the amount varying with different plants. Some plants need full sunlight—day-long exposure to the sun—while some require only partial sunlight. Flowering plants require sunshine for the development of buds, and plants with colored leaves need it to retain their bright colors. Most foliage plants, on the other hand, grow well in indirect light or shade.
Houseplants are usually kept near windows to give them the best possible exposure to light. Generally, windows facing south receive full sunlight during the day, and east and west windows receive partial sunlight—that is, sunlight during the morning or afternoon only. Some of the plants that do well in full sunlight are azaleas, cacti, geraniums, and the shrimp plant. Such plants as African violets, begonias, and coleus grow better in partial sunlight. Many green-leaved, non-flowering plants—such as Chinese evergreen, ivies, philodendrons, and the rubber plant—will grow well in the shade or in north windows, which receive indirect light.
Certain houseplants can grow well in basements and other areas without natural light if placed under a combination of fluorescent and incandescent light for 14 to 16 hours a day. However, maintaining the proper temperature and humidity in these areas is often difficult.
Temperature and HumidityMost house-plants grow best at temperatures between 60° and 70° F (16° and 22° C). Fresh air is good for plants, but they should not be exposed to sudden changes in temperature. Cold drafts from open windows and doors, as well as excessive heat from radiators, can harm them.
Almost all plants grow better in an environment of high (5O to 60 per cent) humidity. Since most heated homes become rather dry in winter, some steps can be taken to provide additional humidity for plants. One way is to spray the plant's foliage once a day with a fine mist of water. Another way is to place a potted plant atop pebbles contained in a saucer filled with water. As the water evaporates, vapor will rise to the leaves of the plant.
WaterHouseplants can die from over-watering as well as from under-watering. Too much water will cause a plant's roots to rot; when this happens there is little chance of reviving the plant. The lower leaves of an overwatered plant fade and drop off, while a plant given too little water will have a noticeable droop in its leaves and stems. A good rule to follow is to water plants when the soil appears grayish and feels dry when rubbed between the fingers.
Once the soil is ready for water, it should be completely soaked. When the plant is watered from the top, excess water will seep out through the drainage hole in the bottom of the pot. It should be collected in a saucer or other container, which should be emptied as soon as the seepage stops; a watered plant should not continue to sit in water.
A plant can also be watered from the bottom; this is done by continually filling a saucer underneath until no more water is taken up into the pot. A third watering method is possible when clay pots are used. Clay is porous and easily absorbs moisture, so the plant can be watered by soaking the pot in a container of water filled to about one inch (2.5 cm) from the rim of the pot. The pot should be removed from the water when the surface soil becomes moist.
SoilMost houseplants will do well in a potting soil mixture of equal parts of builder's sand, peat or sphagnum moss, and loam (topsoil). Builder's sand is coarser than beach sand and promotes better drainage of water. Peat and chopped sphagnum moss are fibrous vegetable materials that absorb water and keep the soil moist. Loam contains plant nutrients and provides the weight and body needed to support the plant and hold it upright.
Plant FoodThe nutrients in the small amount of soil in which potted plants live are continually absorbed by the plant or washed away by waterings. Therefore houseplants need feedings about every two weeks with ordinary garden fertilizer or commercially prepared plant food. Commercial plant foods are available in liquid, powdered, granulated, or tablet form. All plant foods contain three primary ingredients—nitrogen for the healthy growth of leaves and shoots; phosphorus for the development of flowers, fruits, and seeds; and potassium for strengthening stems.
Newly potted or purchased plants should not be fed for at least six weeks, nor should plants be fed during their dormant periods. Most plants become dormant between October and March; during this time they stop producing new growth and do not benefit from feedings. Plant food should be given sparingly because too much will burn the roots. Watering a plant just before feeding will protect the roots from the chance of being harmed by too strong a concentration of fertilizer.
Cultivation of Houseplants
Pots and PottingSeveral types of pots are commonly used for houseplants—the clay pot, the glazed pot, and the plastic pot. Clay pots are porous, permitting the soaking method of watering, but allowing the soil to dry out faster in heated rooms. Glazed ceramic and plastic pots are nonporous and tend to hold moisture longer under such conditions. No matter which pot is used it should have one or more drainage holes in the bottom; without proper drainage, plants will not live long.
Houseplants need repotting when they become top-heavy in their pots; when their roots become a crowded, tangled mass (an indication of this is when new leaves grow smaller and farther apart than normal); or when the roots begin to grow out of the drainage hole. The plant is removed for repotting by placing the stem (or stems) between spread fingers, turning the pot upside down, and gently rapping the sides of the pot against the edge of a table or bench to loosen the plant from the pot. If the plant's roots are tightly matted, they can be gently loosened with the fingers.
The new pot should be about one inch (2.5 cm) larger in diameter than the old one. The drainage holes should be covered with shards (broken pieces of pottery) and these covered with gravel or small pebbles. Next, a thin layer of sphagnum moss should be added to prevent the potting soil above from washing into the gravel layer and out of the pot. Enough potting soil should be added so that when the plant is centered on top of the soil, the beginning of its stern comes to about 3/4 of an inch (2 cm) below the top of the pot. (The empty space at the top prevents overflow when watering.) More soil is then added so that the roots are completely covered. The plant should be watered immediately after potting.
PropagationThere are several relatively quick and easy ways to propagate house-plants without growing them from seed. By these methods mature plants can be the source of smaller, young plants in a short time. The most common methods are by using leaf and stem cuttings, by dividing the roots, and by air layering.
The leaves and stems of many common houseplants will develop roots and new shoots if placed in water or a rooting medium (such as perlite, vermiculite, or sand that is kept moist). The leaf cutting method works with plants such as African violets, gloxinias, echeverias, and sedums, which have fleshy or succulent leaves. Stem cutting can be used with most plants having upright or creeping stems. Propagating plants by dividing their roots is effective with plants that grow in clumps or form more than one crown of leaves; for example, African violets, begonias, the Chinese evergreen, and echeverias. They can be pulled apart so that a few roots will adhere to each section.
The air layering method is usually used for large plants such as the rubber plant, which often grows tall and whose stern grows only a tuft of leaves at the top. By this method a shorter plant can be made from the leafy top portion of the original plant.
First, a small notch is cut in the bare stem a short distance below the last leaf. Moist sphagnum moss is then wrapped around the cut and a piece of plastic is firmly tied around the moss to permit it to retain its moisture. After 7 to 10 weeks, a mass of roots can be seen growing in the moss. The stem should then be cut just below the plastic wrapping. The wrapping is then removed and the newly rooted upper portion of the plant is potted. In many instances the bare, potted stem that remains will grow a new leafy top if watered sufficiently.
PruningHouseplants often thrive so well that their growth becomes overabundant and unattractive and should be controlled by pruning—cutting back the plant with a pair of sharp shears. Plants also need pruning when they lose their bushiness to tall spindly growth. A gentle form of pruning, called pinching, consists of removing the growing tips of the stems with the fingernails. Pinching can encourage lower, fuller growth; when used on flowering plants in their budding stage, it generally produces larger and longer-lasting flowers. (The reason is that the buds receive additional nourishment—that which would have gone into the growing stem tips.)
Controlling Insect PestsHouseplants are occasionally attacked by such pests as aphids, mealybugs, mites, red spiders, and scale insects. These pests thrive in the dry, warm air of heated rooms. Certain species can be discouraged from attacking plants by frequently sponging the leaves or spraying the plants with lukewarm water. Aerosol insecticides or miticides can be used on plants already infested. Most insects lay their eggs under the leaves, so the undersides of leaves as well as the tops should be sprayed.