The jurists concur that no form of zakāh is due on anything that animals produce—except, potentially, honey. Even here they disagreed: the majority hold that honey carries no zakāh, while another group maintains that it does.
The source of the disagreement is their divergent assessment of the report transmitted on the subject. The Prophet ﷺ said: “For every ten skins of honey, one skin is due,” a ḥadīth related by al-Tirmidhī and others. Those who deem the report sound obligate zakāh on honey; those who do not, exempt it.
Turning to vegetation, after agreeing that zakāh is unquestionably due on the four kinds already mentioned, they differed over which other plants fall under the obligation.
• Some restricted zakāh to those four categories alone; this is the view of Ibn Abī Laylā, Sufyān al-Thawrī, and Ibn al-Mubārak.
• Others, among them Mālik and al-Shāfiʿī, held that zakāh is due on every storable crop that serves as a staple food.
• A third opinion, represented by Abū Ḥanīfah, imposes zakāh on everything the earth produces, save herbage, firewood, and reeds.
The first axis of disagreement—between those who confined the duty to the agreed-upon four kinds and those who extended it to all storable staples—turns on whether the obligation is linked to the kinds themselves or to an attribute they possess, namely their function as staple food. Whoever tied the ruling to the kinds themselves kept the obligation exclusive; whoever saw the cause in their being staples generalised the ruling to every staple.
The second axis—between those who limited zakāh to staples and those who imposed it on all produce except what consensus has excluded (herbage, firewood, reeds)—is the tension between analogy (qiyās) and the general purport of the wording.
The wording that conveys generality is the Prophet’s statement, “On what rain waters a tenth is due, and on what is irrigated by labour, half a tenth,” together with the Almighty’s words, “He is the One who produces gardens, trellised and untrellised…,” up to “and give its due on the day of harvest” (Q 6:141).
Analogy argues that the aim of zakāh is to relieve need, which in most cases is achieved only through staples. One who restricts the general wording by this analogy exempts non-staple crops; one who gives precedence to the general wording obligates zakāh on them as well, except for the items excluded by consensus.
Finally, even those who agree that zakāh pertains only to staples differ over particular crops: Are they truly staples, and may they be analogically linked to the items about which consensus already exists?