In the garden, to sing for us is a good thing (5)
I believe the answer is:
humus
'in' is the definition.
The definition and answer can be both substances as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'garden to sing for us is a good thing' is the wordplay.
I cannot really see how this works, but
'sing' could be 'hum' (humming is a kind of singing) and 'hum' is found within the answer.
'us' is found in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'the' is the link.
Can you help me to learn more?
(Other definitions for humus that I've seen before include "Fertilising agent" , "Organic matter in topsoil" , "Organic "fertiliser"" , "Organic stuff" , "decomposing organic matter" .)