Took up tot found in grass (7)
I believe the answer is:
resumed
'took up' is the definition.
('resume' can be a synonym of 'take up')
'tot found in grass' is the wordplay.
'tot' becomes 'sum' (synonyms).
'found in' is an insertion indicator.
'grass' becomes 'reed' (I've seen this before).
'sum' inserted into 'reed' is 'RESUMED'.
(Other definitions for resumed that I've seen before include "Once again picked up" , "Carried on again" , "Restarted" , "came into play again" , "got to work on again" .)