Right on call the writer gets refinement in gardening (12)
I believe the answer is:
horticulture
'gardening' is the definition.
(I know that gardening can be written as horticulture)
'right on call the writer gets refinement' is the wordplay.
'right on call' becomes 'hort' (I can't justify this - if you can you should believe this answer much more).
'the writer' becomes 'I' (where the crossword setter is 'Bartland').
'gets' says to put letters next to each other.
'refinement' becomes 'culture' (I've seen this before).
'hort'+'i'+'culture'='HORTICULTURE'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for horticulture that I've seen before include "after grasses etc" , "What gardener does" , "Science of gardening" .)