Is it permissible to sell fruit crops before they ripen, provided that the price per kilogram of fruit is determined after full ripening and delivery?

The mentioned case is not permissible, and the sale is void because it is a sale of fruit before its ripeness becomes apparent, which is a prohibited form of gharar (excessive uncertainty). This is based on the hadith where the Prophet (peace be upon him) forbade the sale of fruits before their ripeness becomes apparent.

It is permissible to sell the fruit of the entire orchard once its ripeness becomes apparent, even if only on some trees, provided that watering is the responsibility of the seller. If the fruit is afflicted by a blight before harvest, the price is forfeited, and the seller is not allowed to take anything.

Alternatively, a salam contract can be concluded. In this type of contract, the buyer pays a known price in advance, and the seller delivers a known weight of a specific fruit after a known period. It is not a condition for the fruit to exist at the time of the contract, but rather for it to be available at the time of delivery. The permissibility of salam is supported by the hadith narrated by Ibn Abbas (may Allah be pleased with him), where the Prophet (peace be upon him) said: "Whoever pays in advance for something, let him pay for a known measure, a known weight, to a known term."