Light Light is probably the most essential factor for indoor 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. Indoor plants can be classified according to their light needs by high, medium, and low light requirements. The direction the windows in your home face will affect the intensity of natural sunlight that plants receive. A southern exposure is the warmest, eastern and western are less warm, and a northern exposure is the coolest.