Narrated Abu Bakhtari at-Tai:I asked Ibn `Abbas about Salam for (the fruits of) date-palms. He replied "The Prophet (ﷺ) forbade the sale a dates on the trees till they became fit for eating and could be weighed." A man asked what to be weighed (as the dates were still on the trees). Another man sitting beside Ibn `Abbas replied, "Till they are cut and stored." Narrated Abu Al-Bakhtari: I heard Ibn `Abbas (saying) that the Prophet (ﷺ) forbade ... etc. as above.
حَدَّثَنَا آدَمُ، حَدَّثَنَا شُعْبَةُ، أَخْبَرَنَا عَمْرٌو، قَالَ سَمِعْتُ أَبَا الْبَخْتَرِيِّ الطَّائِيَّ، قَالَ سَأَلْتُ ابْنَ عَبَّاسٍ ـ رضى الله عنهما ـ عَنِ السَّلَمِ، فِي النَّخْلِ. قَالَ نَهَى النَّبِيُّ صلى الله عليه وسلم عَنْ بَيْعِ النَّخْلِ، حَتَّى يُؤْكَلَ مِنْهُ وَحَتَّى يُوزَنَ. فَقَالَ الرَّجُلُ وَأَىُّ شَىْءٍ يُوزَنُ قَالَ رَجُلٌ إِلَى جَانِبِهِ حَتَّى يُحْرَزَ. وَقَالَ مُعَاذٌ حَدَّثَنَا شُعْبَةُ، عَنْ عَمْرٍو، قَالَ أَبُو الْبَخْتَرِيِّ سَمِعْتُ ابْنَ عَبَّاسٍ ـ رضى الله عنهما ـ نَهَى النَّبِيُّ صلى الله عليه وسلم مِثْلَهُ.
Bukhari
Sales in which a Price is paid for Goods to be Delivered Later (As-Salam) • Hadith 9