As for what sprouts from the earth other than grains and fruits, these are quick-yielding crops whose benefit is enjoyed immediately, their quantities are usually small, and they are cultivated for comfort and enjoyment. Supporting this is the report: “As for cucumbers, melons, pomegranates and cane, the Messenger of Allah ﷺ pardoned them.” Even though the hadith is weak, it agrees with the established principle that no zakat is imposed on matters left unspoken; therefore, they are deemed exempt.
The Prophet ﷺ said: “He has kept silent about certain things as a mercy to you, not out of forgetfulness, so do not ask about them.” Reported by al-Tabarani in al-Awsat (8938) and by al-Daraqutni (4/298). Al-Nawawi and al-Samʿani graded it hasan, while al-Hakim declared its chain sound; other narrations support its wording and meaning.
The produce on which zakat is due has been determined by its legal measure, whereas fruits, vegetables, legumes and the like are reckoned by count, and thus are not included in what carries the obligation of zakat.
Al-Khattabi said that hadith 508 indicates zakat is not due on any vegetables, fruits, and the like, and this is the view of the vast majority of scholars. The fact that the Prophet ﷺ himself refrained from taking it, and his successors likewise—despite such crops being grown alongside them and no zakat being taken—demonstrates that it is not obligatory; indeed, leaving it untaken is the sunnah to be followed.
The two Imams, Malik and al-Shafiʿi, hold that zakat on fruits applies only to dates and raisins, and on grains only to what is a staple food.
Imam Ahmad, however, considers it obligatory on every fruit that is measured by volume and can be stored, and on all varieties of grain, even if they are not staple foods.
Shaykh al-Islam Ibn Taymiyyah has previously stated that the decisive factor for zakat on agricultural produce is its storability, for that is the rationale that justifies levying zakat on it. Measuring by volume is merely an estimate, and weighing comes under the same category.