From Sahih Bukhari (Hadith 2203):
Narrated Nafi', the freed slave of Ibn 'Umar:If pollinated date-palms are sold and nothing is mentioned (in the contract) about their fruits, the fruits will go to the person who has pollinated them, and so will be the case with the slave and the cultivator. Nafi' mentioned those three things
Reference: Bukhari 2203