Musannaf Ibn Abi Shayba 13:1850

Abu Bakr narrated to us, he said: Abu al-Ahwas narrated to us, from Abu Ishaq, from al-Aswad, who said: There is no *salam* (forward sale) in date palms until they turn yellow or red. And there is no *salam* in chicks until they reach maturity. And there is no *salam* in crops while they are green until they produce ears.