Harita is a form of Goddess Gauri, the consort of Shiva, when she becomes the mother of Lord Ganesha.
Legend has it that Goddess Parvati chose Shiva as her husband, even after hearing the contrary decision of her father, to get her married to Vishnu. To achieve her goal, she left her house and observed vrata (penance) in the forest, along with her friends. The firm resolve and true devotion made her achieve her goal. The day on which Gauri observed her vrata is worshipped and celebrated as Haritalika, which falls on the third day of Bhadrapada month.
Another legend says that Gauri decorated herself with haritala (turmeric) and so she is called Harita Gauri. The day on which she removed her turmeric application and cast it into an idol was birth of Ganesha. It is celebrated as Ganesh Chaturthi.
The name Harita is also found in scriptures where she is identified as the power of Hari (Vishnu). She is also worshipped as the Goddess of prosperity, greenery and vegetation.
Harita is the Goddess of verdant vegetation and her presence is felt all through the month of Bhadrapad (sometime around August – September) in lush green fields.