I asked Ibn ʿUmar about Salam for dates. Ibn ʿUmar replied, "The Prophet ﷺ forbade the sale (the fruits) of date-palms until they were fit for eating and also forbade the sale of silver for gold on credit." I also asked Ibn ʿAbbas about it. Ibn ʿAbbas replied, "The Prophet ﷺ forbade the sale of dates till they were fit for eating, and could be weighed." I asked him, "What is to be weighed (as the dates are on the trees)?" A man sitting by Ibn ʿAbbas said, "It means till they are cut and stored."
نَهَى النَّبِيُّ ﷺ عَنْ بَيْعِ الثَّمَرِ حَتَّى يَصْلُحَ وَنَهَى عَنِ الْوَرِقِ بِالذَّهَبِ نَسَاءً بِنَاجِزٍ وَسَأَلْتُ ابْنَ عَبَّاسٍ فَقَالَ نَهَى النَّبِيُّ ﷺ عَنْ بَيْعِ النَّخْلِ حَتَّى يَأْكُلَ أَوْ يُؤْكَلَ وَحَتَّى يُوزَنَ قُلْتُ وَمَا يُوزَنُ قَالَ رَجُلٌ عِنْدَهُ حَتَّى يُحْرَزَ