Tu B’Shvat is a Jewish holiday in the Hebrew month of Shevat, usually in late January or early February, that marks the "New Year of the Trees". Tu B’Shvat is one of four New Years mentioned in the Mishnah. (Normally, we only hear about Rosh Hashanah!) Customs include planting trees and eating dried fruits and nuts, especially figs, pomegranates, dates, almonds, and carob.
In the 1600s, the mystic kabbalist Rabbi Isaac Luria, of Safed, and his disciples instituted a Tu B’Shvat Seder in which the fruits and trees of Israel were given symbolic meaning. The main idea was that eating ten specific fruits and drinking four cups of wine in a specific order while reciting the appropriate blessings would bring human beings, and the world, closer to spiritual perfection.
The mystical kabbalistic Tu B’Shvat Seder has been revived, and is now celebrated by many Jews, religious and secular. Special haggadot have been written for this purpose. In many communities, Tu B’Shvat has become the Jewish Earth Day and a time to reflect on environmental issues, our earth, our food sources and the human connection to our surroundings.