Does the farmer pay the zakat on olives from their selling price after they ripen while still on the trees, or does he add the harvesting cost to that?

The obligation of Zakat (definition) on olives is a matter of scholarly disagreement. According to the view that it is obligatory, Zakat is not due unless the quantity reaches five wasqs (a wasq is sixty sa's, and a sa' is approximately 2040 grams of good wheat). The full tithe (one-tenth) must be given if the olives were irrigated by rain, and half the tithe (one-twentieth) if they were irrigated by artificial means. The farmer was originally obligated to give Zakat from the olives themselves before selling them. Since he sold them, he should purchase olives equivalent to the amount due and pay their Zakat from their oil, or he may pay it from the proceeds of the sale if that is more beneficial for the poor. In this case, he should pay Zakat from the entire proceeds and not deduct the harvesting cost.