The Prophet ﷺ forbade the sale of grain ears until they whiten and are safe from blight. He forbade this for both the seller and the buyer.
حدثنا أحمد بن منيع، حدثنا إسماعيل بن إبراهيم، عن أيوب، عن نافع،
أن النبي ﷺ نهى عن بيع السنبل حتى يبيض ويأمن العاهة نهى البائع والمشتري.
Muslim also narrated it, see the previous hadith. On this topic there are also narrations from Anas [coming up: 1228], Ayesha [Ahmad: 6/70, 105], Abu Hurairah [Muslim, no: 538], Ibn Abbas [Bukhari, no: 2246 and Muslim, no: 1537], Jabir [Bukhari, no: 1487 and Muslim, no: 1536], Abu Saeed [Tabarani in al-Awsat, no: 6412], and Zayd bin Thabit [Abu Dawud, no: 3372 and Ahmad: 5/185, 190].