Match plants to specific conditions. All plants need light to manufacture food, but the amount needed varies from one plant to another. Most houseplants thrive in moderate to bright, indirect light. Flowering plants and those with colored leaves usually need higher light levels than plants with green leaves. And a select group of plants, including the popular Chinese evergreen and cast-iron plant, will tolerate very low light levels.
Plants show signs of stress when light levels are too low or too high.
Weak, spindly growth indicates insufficient light. Variegated foliage will lose all or part of its markings. Signs of too much light are bleached or wilting leaves on plants like scheffleras, philodendrons, ferns and peperomias. In this case, move plants farther from the glass or filter light with a sheer curtain. Most houseplants originate in tropical or semitropical regions, where the air is moist.