Soluble Salts Light, water, temperature, humidity, ventilation, fertilization, and soil are chief factors affecting plant growth, and any one of these factors in incorrect proportions will prevent proper plant growth indoors. Light Light is probably the most essential factor for house plant growth. The growth of plants and the length of time they remain active depend on the amount of light they receive. Light is necessary for all plants because they use this energy source to photosynthesize.
Light intensity influences the manufacture of plant food, stem length, leaf color, and flowering.
A geranium grown in low light tends to be spindly and the leaves light green in color. A similar plant grown in very bright light would tend to be shorter, better branched, and have larger, dark green leaves. House plants can be classified according to their light needs, such as high, medium and low light requirements. The direction the windows in your home face will affect the intensity of natural sunlight that plants receive. Southern exposures have the most intense light, eastern and western exposures receive about 60 percent of the intensity of southern exposures, and northern exposures receive 20 percent of a southern exposure.