HO-39
Indoor Plant Care
HOME YARD & GARDEN • COOPERATIVE EXTENSION SERVICE
DEPARTMENT OF HORTICULTURE • PURDUE UNIVERSITY • WEST LAFAYETTE, IN
by Juliann Chamberlain

Indoor plants help create a pleasant home environment. Small plants add color and scenery to windows or tables, while larger ones soften and blend with groups of furniture. As a part of the "indoor landscape," plants create a cool, spacious feeling, even in the warmest weather.
If you have been puzzled as to why some indoor plants thrive while others refuse to flourish, this publication is for you. Most indoor plant problems can be easily corrected and even more easily prevented.
First, realize that most of the foliage plants known as house plants are native to tropical areas. This is why, for instance, most indoor plants prefer a humid atmosphere and indirect light. Of course, there are exceptions, and these are also discussed. Keep in mind that sound cultural methods, preventive care, knowing your plant’s requirements, and careful attention are the best substitutes for a green thumb.

Light
This publication includes a partial guide to the light requirements of some common indoor plants. Use it as a guide for the selection and placement of your plants. See Tables 2-4.
Plants vary considerably in their light requirements. For example, plants such as the croton need direct sunlight, while philodendrons will grow under lower light intensities. If plants are not receiving enough light, their leaves turn yellow and die.
Most people depend on natural window light for the growth of their plants. Natural light may be adequate if plants are close to windows. However, the amount of natural light a plant receives, decreases dramatically the farther it is placed from the window or its source of light. Usually, plants must be located close to windows to receive enough light for them to grow and flourish.
If window sill space is in short supply, hang basket planters, make glass shelves, or build a "bay window greenhouse" by extending the window and adding shelves for plants that require higher light
intensities. Light from reading lamps is also beneficial, but the new "broad spectrum" fluorescent lights are usually better. Generally, artificial, fluorescent light 10 to 14 inches above the plants will provide sufficient light for plants requiring medium light intensity, such as the pothos. A combination of one warm white to one cool white light is best. If your plants appear spindly, they need more light, should be closer to artificial light, or your fluorescent light bulbs are too old to produce the proper wavelength for growth and should be replaced. For even growth, turn the plants once a week so they receive light on all sides.

Temperature and Ventilation
Most indoor plants grow well between 60 and 75° F. They may become spindly if kept warmer. Always keep plants away from hot or cold drafts, warm appliances, and heat registers. Flowering plants will retain blossoms longer if lower temperatures are provided. Temperatures above 75°F hasten the death of flowers and make plants spindly as well as less resistant to disease and insect attack.
Some plants will thrive in hot and dry conditions. Table 1 cites examples of such plants.
Proper ventilation is necessary for good plant growth. In most homes, ample fresh air is provided. However, guard against escaping fumes from gas appliances or furnaces.

Humidity
Most plants require a higher humidity than that of the average home. Any means of increasing humidity will be beneficial to your plants. Today many heating systems are provided with humidifiers, which should be kept full of water. Sprinkling or syringing plants with water is not effective as the water evaporates rapidly. Fittonia (Fittonia verschaffelti), baby’s tears (Helxine soleiroli), and strawberry begonia (Saxifraga sarmentosa) will tolerate high humidity conditions. Growing plants together in a terrarium or setting them on a tray of gravel with moisture in the tray are good ways to raise humidity.