When is it permissible to sell dates while they are still on the palm trees?

It is permissible to sell dates on the palm trees after their ripeness becomes apparent, by turning red or yellow. This ripeness does not require complete maturity or that it be present in all the fruit. Rather, it is sufficient for ripeness to appear in part of a single fruit or on a single tree of the same type. Excluded from this ruling is selling the fruit with the tree, or selling it with the condition of immediate harvesting. In these two cases, selling is permissible even if ripeness has not appeared.