Tu B’Shevat, which translates literally as the 15th day of the month of Shevat, is the Jewish New Year for Trees. Mentioned in the Talmud, the holiday marks the tithing of fruits grown in Israel.
In the 16th century, Jewish mystic Rabbi Isaac Luria and his disciples developed a seder for the holiday that focused on the symbolism of the fruits and trees of Israel. Like the Passover seder, the Tu B’Shevat one includes four cups of wine, each representing a different sphere in kabbalah. The first glass of wine is all white; the fruit is inedible on the outside and edible inside. The second glass of wine is equal parts white and red wine; the fruit is edible outside and inedible inside. The third glass wine is mostly red and some white; the fruit is completely edible. The last glass of wine is all red; the fruit is “spiritual sustenance.”
The celebration of this holiday has experienced resurgence recently, celebrated as a Jewish Earth Day.