The traditional Iranian Nowruz picnic held on the thirteenth day is called Sizdah Bedar.
Sizdah Bedar takes place on the thirteenth day of Farvardin, the first month of the Iranian Solar Hijri calendar. Families traditionally leave their homes for parks, countryside or other outdoor spaces, where they picnic, socialize and spend the day outdoors. It is widely regarded as the closing celebration of the Nowruz holiday period.
A well-known custom is taking the sprouted greens from the Haft-sin display outdoors. Some people tie the shoots before releasing them into flowing water, although practices vary and environmental concerns have encouraged more responsible disposal.
Sizdah means thirteen, while bedar is commonly interpreted in the phrase as “getting rid of” or “out in nature.” It is different from Chaharshanbe Suri, the fire-jumping observance held before Nowruz, and from Yalda, the winter-solstice celebration.