Most plants require a certain amount of light (intensity and duration) to maintain old leaves and produce new ones of the same size and color. Reduced leaf size, increased internode length, changes in stem orientation, and loss of old leaves are some of the signs that more light is needed.
In general, too much light causes plant stunting. Even with no superficial symptoms, internal damage may occur that produces this. Leaves curl and may appear pale, edged with red. Plants that have been allowed to dry are susceptible to sunburn. Excessive heat and light break down chlorophyll, bleaching leaf tissues. Some plants may suffer leaf discolorations. Pruning damaged leaves, reducing light, and watering properly restore good growth.