Good variety in farm (6)
I believe the answer is:
grange
'farm' is the definition.
(grange is a kind of farm)
'good variety' is the wordplay.
'good' becomes 'g' (abbreviation).
'variety' becomes 'range' (I've seen this before).
'g'+'range'='GRANGE'
'in' acts as a link.
(Other definitions for grange that I've seen before include "US lodge" , "Country house with outbuildings" , "Ganger in country house with farm buildings" , "Country-house" , "Country house with attached farm buildings" .)