Sayyiduna Jabir bin Abdullah (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) said: "There is no zakah on a Muslim man's grapes or grain so long as it is less than five wasqs (20 maunds)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7472