the Messenger of Allah ﷺ forbade selling fruits until they have changed the color, and selling grapes until they have turned black, and selling grains until they have hardened.
أَنَّ رَسُولَ اللَّهِ ﷺ نَهَى عَنْ بَيْعِ الثَّمَرَةِ حَتَّى تَزْهُوَ وَعَنْ بَيْعِ الْعِنَبِ حَتَّى يَسْوَدَّ وَعَنْ بَيْعِ الْحَبِّ حَتَّى يَشْتَدَّ