The Prophet ﷺ forbade selling grapes until they turn black and selling grain until it hardens.
حدثنا الحسن بن علي حدثنا أبو الوليد عن حماد بن سلمة عن حميد
أن النبي ﷺ نهى عن بيع العنب حتى يسود وعن بيع الحب حتى يشتد
Its chain is daif.Tirmidhi transmitted it in the Book of Sales, Chapter on the dislike of selling fruit before its soundness becomes evident, hadith no. 1228, from Hasan bin Ali, and he said it is hasan gharib. Ibn Majah also narrated it, hadith no. 2217. Hakim graded it sahih according to the criterion of Muslim, 2/19, and Dhahabi agreed with him. Humayd Tawil is a mudallis and he narrated using the word "an" (indicating possible concealment of the chain).