It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "The sale of fruits is not valid until they have ripened well."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 4869
Hadith Gradingحکم دارالسلام:حديث صحيح، م: 1535، وهذا إسناد حسن من أجل محمد بن عمرو