The two week long Nowruz celebrations end with Sizdah Bedar. Also referred to as Nature Day, Sizdah Bedar is an ancient Iranian festival of joy and solidarity; and part of Nowruz celebration rituals which is annually held on the 13th day of Farvardin (first month in Iranian calendar).
It is customary for Persians to celebrate this day by going outdoors to have a picnic and spend the day in nature. Picnic items are set out and kebabs are grilled. Music and chanting local songs are also common ceremonies of the day. The time spent outdoors with family members and friends is filled with joviality and happiness.
A ritual performed on this day is to throw away the 'Sabzeh’, Nowruz sprouts, in a running stream or river. The action of throwing away the Sabzeh symbolizes removing all the sickness, pain and ill fate.
Another tradition on this day is knotting of grass blades by unwed youths while making a wish to find a companion. The knotting of the grass represents love and bondage of a man and a woman.