Most likely, if your basil plant is wilting, it was probably overwatered. If basil plants receive either excessive or insufficient water, they typically wilt. It is likely to start decaying and the leaves start to fall off if you irrigate a basil plant that has been improperly overwatered. Wilted leaves are a sign that something is amiss with the plant. Though less frequent than overwatering, underwatering does happen occasionally. By looking at the dirt near the base of the stems of your basil plant, you may determine if it is underwatering. Your plant may be experiencing under-watering if there is any standing water close to the stem's base.