From Sahih Bukhari (Hadith 2205):
Narrated Ibn `Umar:Allah's Messenger (ﷺ) forbade Al-Muzabana, i.e. to sell ungathered dates of one's garden for measured dried dates or fresh ungathered grapes for measured dried grapes; or standing crops for measured quantity of foodstuff. He forbade all such bargains
Reference: Bukhari 2205