Leaves turn yellow because of lack of water and insects. Chlorosis, root issues, lack of nutrients and lack of sunlight are also culprits that cause yellow leaves.
If the location of the plant with yellow leaves is indoors, the soil surrounding the plant may be dry, indicating that it is in need of water. This is solved by placing the plant pot on a small plate or a pie pan to catch access water. This helps the plant roots absorb the water when needed. Plant leaves and stems should be inspected for signs of insects. Different bugs are attracted to different types of plants and have the ability to cause yellow leaves. If insects are found, an insecticide can be applied as long as it is safe for use on the specific type of plant. Insecticides and plants that have been treated with them must be kept out of reach of children and animals. Chlorosis is a condition which occurs when yellow leaves lack the green pigment known as chlorophyll. Roots which show signs of compaction, such as roots that protrude from the bottom of the pot, do not get the proper nutrients to feed the plant. These can be placed in a larger pot, leaving some soil around the roots, and filled with new soil. Plants that do not receive adequate sunlight also produce yellow leaves; revive the plant by placing it in a location that receives more sunlight.