It is narrated from Hazrat Abu Saeed (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "There is no zakat on silver less than five uqiyah, no zakat on camels less than five, and no zakat on wheat less than five wasq."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 11030