When does the prohibition on selling grain cease?
Chapter on Selling Assets and Fruits
Al-Mughni
Book of Sales
Primary text
The sale of grain becomes permissible absolutely, and with the condition of retention (tabqiyah), once the grain has hardened (ishtadda habbuhu). This is inferred from the Hadith stating the prohibition continues until it whitens, which signifies the end point of the prohibition, thus indicating permissibility thereafter. A narration in ms1850 specifies that the Prophet (peace be upon him) prohibited the sale of grapes until they darkened and the sale of grain until it hardened. The justification is that when the grain hardens, its readiness for use becomes apparent, equating it to fruit once its readiness appears.
Supporting text
If even a portion of the grain hardens, the sale of the entire yield of that type within the orchard becomes permissible, similar to the ruling concerning a tree where readiness has become apparent in one part of its fruit.