Musannaf Ibn Abi Shayba 35:157

Ya'la ibn 'Ubayd narrated to us, Fudayl ibn Ghazwan narrated to us, from Ibn Abi Nu'm, from Abu Hurayrah, that the Messenger of Allah (may Allah bless him and grant him peace) forbade the selling of fruit until its ripeness becomes apparent. And he mentioned that Abu Hanifah said: "There is no harm in selling it while it is still green (balah)," and this is contrary to the tradition (athar).