Sayyiduna Sahl bin Abi Hathmah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) forbade selling the fruit on the tree for dried dates and said: "That is usury (riba); that is muzabanah." But he granted a concession in the 'ariyyah sale, since the members of a household would take one or two date palms in exchange for dried dates by estimation, and then eat fresh dates.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10657