Ruling 1882
If the owner of some wheat, barley, dates, or grapes dies after zakat on them has become obligatory, the zakat on them must be given from his estate. However, if he dies before zakat on them becomes obligatory, each of the heirs whose share reaches the niṣāb must give zakat on their share.
-Ayatullah Sistani, Practical Laws of Islam, Alms Tax (Zakat)