Small unit of capacity prepared for the ground (4-5)

'small' is the definition.
(thesaurus)

'unit of capacity prepared for the ground' is the wordplay.
I cannot really see how this works, but
'unit' could be 'pint' (pint is a kind of unit) and 'pint' is found within the answer.
'capacity' could be 'size' (I've seen this in another clue) and 'size' is present in the answer.
A single letter 'd' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?