Imam Ad-Daraqutni related on the authority of Mu'adh (RAA), 'As for cucumbers, watermelons, pomegranates, and sugar-cane, the Messenger of Allah (ﷺ) has exempted them from Zakah.' It is transmitted with a weak chain of narrators. (AR)
English reference (AR): Book 4, Hadith 639 (AR)
Arabic reference (AR): Book 4, Hadith 617 (AR)