[Machine] Narrated by the Prophet that he allowed the sale of wheat in its stalks when it turns white, and he said, "As for it, it is a type of gharar (uncertainty)." Because it goes through a transformation that cannot be seen. If this narration from the Prophet is established, then we say it is permissible. This ruling was derived from a specific situation that occurred during a particular year. The Messenger of Allah prohibited selling gharar, but he allowed this.  

عَنِ النَّبِيِّ ﷺ أَنَّهُ أَجَازَ بَيْعَ الْقَمْحِ فِي سُنْبُلِهِ إِذَا ابْيَضَّ فَقَالَ أَمَّا هُوَ فَغَرَرٌ؛ لِأَنَّهُ مَحُولٌ دُونَهُ لَا يُرَى فَإِنْ ثَبَتَ الْخَبَرُ عَنِ النَّبِيِّ ﷺ قُلْنَا بِهِ وَكَانَ هَذَا خَاصًّا مُسْتَخْرَجًا مِنْ عَامٍّ؛ لِأَنَّ رَسُولَ اللهِ ﷺ نَهَى عَنْ بَيْعِ الْغَرَرِ وَأَجَازَ هَذَا