Plant hormones (also known as phytohormones) are chemicals that regulate plant growth. Plant hormones are signal molecules produced within the plant and occur in low concentrations. Hormones regulate cellular processes in targeted cells locally and move to other functional parts of the plant. Hormones also determine the formation of flowers, stems, leaves, the shedding of leaves and the development and ripening of fruits. Plants, unlike animals, lack glands that produce and secrete hormones. Instead, each cell is capable of producing hormones. Plant hormones shape the plant, affects the seed growth, time of flowering, the sex of flowers, senescence (the process of deterioration with age) of leaves and fruits. They affect the tissues which grow upward and downward, leaf formation and stem growth, fruit development and ripening, plant longevity and even plant death.Hormones are vital to plant growth. If plants are hormone deficient, they would become a mass of undifferentiated cells. Hence plant hormones are also known as growth factors or growth hormones.