Sunan an Nasai
2485
Sahih+2

It was narrated from Abu Sa'eed Al-Khudri that the Prophet said:"No Sadaqah is due on grains or dates unless the amount reaches five Awauq, nor on less than five Dhawd, nor on less than five Awaq

SahihAbu Ghuddah
SahihAl-Albani