Parsley can turn yellow for several reasons. If the soil was already waterlogged, it may mean that the roots need to dry out. Your plant may have developed a disease due to the moist conditions, such as crown rot. If the disease progresses, you may need to discard the plant. Do not water until the soil is semi-dry. Water sparingly for a while, only at the base; provide good air circulation and sunlight; and avoid abrupt changes in temperature. Hopefully, the plant will recover. Also check for signs of insects, which may have been drawn to the sickly plant.
Parsley can turn yellow for several reasons. If the soil was already waterlogged, it may mean that the roots need to dry out. Your plant may have developed a disease due to the moist conditions, such as crown rot. If the disease progresses, you may need to discard the plant. Do not water until the soil is semi-dry. Water sparingly for a while, only at the base; provide good air circulation and sunlight; and avoid abrupt changes in temperature. Hopefully, the plant will recover. Also check for signs of insects, which may have been drawn to the sickly plant.