Sayyiduna Mu'adh (may Allah be pleased with him) said: When the Messenger of Allah (peace and blessings be upon him) sent me to Yemen, he instructed me to collect a tenth (1/10) of the produce as zakat from those fruits that grow with the moisture of the land, and to take a twentieth (1/20) as zakat from those irrigated by camels.
Brief Explanation
(Hadith Explanation 1704)
Maulana Waheeduz-Zaman sahib rahimahullah has written: The creed of the Ahl al-Hadith is that zakat becomes obligatory on wheat, barley, millet, dates, and grapes when their quantity reaches five wasq or more. Apart from these, there is absolutely no zakat on other things such as vegetables and fruits, no matter how much they may be.
Qastallani has said: Among fruits, zakat is only on dates and grapes, and among grains, zakat is on every type of grain that is stored, such as wheat, barley, millet, lentils, mung beans, bajra, chickpeas, beans, etc.—zakat is due on all of these. According to the Hanafis, there is no restriction of five wasq; whether the amount is little or much, zakat is obligatory on all. And Imam Bukhari rahimahullah has brought this hadith to refute their view. In summary, when the mentioned crops reach five wasq, if they are irrigated by rainwater, river, etc., then one-tenth is due as zakat; and if the crops are irrigated by well water, or by water drawn by camel or ox, then upon reaching five wasq, half of one-tenth (i.e., one-twentieth) is due as zakat. And this is a very just system of the religion of mercy, in which there is nothing but goodness and blessing.