Is it permissible to lease land to someone who will grow drugs on it, given that there is no other tenant?

If you know that the tenant will plant drugs on the land, then it is not permissible for you to rent it to him, because that is aiding in sin and transgression. Allah Almighty says: (And cooperate in righteousness and piety, but do not cooperate in sin and aggression). Your disavowal of what he will plant on it, despite your knowledge of the drugs, will not benefit you.