Hades changed her name to Persephone and convinced her to eat the seeds of the pomegranite, which symbolized the consummation of their marriage.
Demeter was very distressed that her beloved daughter was missing and looked everywhere for nine days, but with no success. In despair, she finally paid a visit to the Sun god Helios, who told her that her brother Zeus had given her daughter to Hades.
This made Demeter furious. After wandering the Earth disguised as an old woman, she settled in her temple at Eleusis. Here she placed a curse on the Earth that it would no longer be able to produce any vegetation of any kind.
Zeus became frantic and sent her a message as to why she had done this. She told Zeus that the curse of no crops would continue until her her daughter was returned.
Zeus sent Hermes into the Underworld to find Kore-Persephone. Hades did not want to lose his new wife and reminded Zeus that she had eaten the pomegranite seeds. Upon learning of this trick, Demeter went into a great despair, until Zeus declared that Persephone-Kore would live with her husband during half of the year, and return to live with her mother during the other half.
Demeter was pleased enough with this arrangement that she lifted her curse so that Earth could again become green.
And this creates Spring at the time of her great joy when her daughter returns each year; and Fall at her time of great sorrow when her daughter returns to the Underworld to live with her husband, Hades.