Why Are My Basil Plant's Leaves Drying Up?

Light and Heat

• Basil needs light and heat in order to grow properly. However, too much light and heat could cause basil leaves to dry out. The leaves may be brown or darker in color, withered and crumbly. In cases of overheating, dried leaves may litter the area surrounding the basil plant, also. The drying may extend to the basil plant's stem and flowers.

Water

• Basil is known as a heavy feeder, meaning it requires lots of water and fertilizer to keep up with its growing needs. While moist soil is preferable, basil is acclimated to growing in warm, dry conditions and can tolerate having its soil dry out slightly between waterings. If the soil becomes too dry, however, the basil plant begins to dry out, starting with its leaves. Other ways to determine if soil is too dry include looking to see if soil has pulled away from the sides of the container the basil grows in, or sticking your finger 1 inch into the soil to feel for dryness.

Pests

• Garden pests, such as insects, attack basil plants. Aphids, beetles and mites are all insects that feed off of the fluids inside the stems and leaves of basil. As the fluids are sucked from the plant by insects, the leaves begin to dry out and shrivel up. Protect your basil from pests by inspecting the plants regularly and plucking off pests when possible. Treat plants with insecticides or soap sprays to smother pests and keep your basil healthy.

Disease

• Just as it is not immune to pests, basil is not immune to plant disease. Fungal and bacterial disease spread by pests, other plants and the soil may cause leaves to dry out if left untreated. Other signs of disease on your basil include wilting, spotty or discolored leaves and rotten spots on the plants. Treat your basil for disease by using anti-fungal or antibacterial plant sprays. Another treatment option is to pour compost teas over the plants, as these kill disease and fertilize the soil the basil grows in.