Small fruit put underground, by the sound of it (5)
I believe the answer is:
berry
'small fruit' is the definition.
(I've seen this in another clue)
'put underground by the sound of it' is the wordplay.
'put underground' becomes 'bury' (I've seen this before).
'by the sound of it' indicates a 'sounds like' (homophone) clue.
'bury' is a homophone of 'BERRY'.
(Other definitions for berry that I've seen before include "Small succulent fruit" , "Smal pulpy fruit" , "Word linking black or blue" , "Small juicy fruit" , "Pulpy edible fruit" .)