There are total of three main Teej festivals associated with the months of Sawan and Bhadrapada namely Hariyali Teej (August 19), Hartalika Teej (September 18) and Kajri Teej (September 2).
The Hariyali Teej festival is also celebrated to remember the reunion of Shiva and Parvati, the day when Shiva accepted Parvati as his wife. Parvati fasted and was austere for many years and was accepted by Shiva as his wife in her 108 birth. Parvati is also known as Teej mata (lit. Teej mother)
You must eat only after doing the puja. Meals should be prepared with utmost cleanliness and food that is not allowed during fast like brinjal or masoor dal should not be consumed. Some rituals are similar to jyutiya and chhath.
Can unmarried girls do Teej?
It is believed that it was on the day of Hartalika Teej, Lord Shiva had accepted Parvati. Parvati was married to Lord Shiva with her father's blessing evetually. So every year Hartalika Teej is celebrated by both married and unmarried Hindu women.
Thus, the pious festival of Teej honors the devotion of Goddess Parvati who underwent penance for years to become the consort of Lord Shiva. Women seek her blessings for a happy married life and unmarried girls fast to attain an exemplary husband like Shiva