Can put up the price for fertiliser (7)
I believe the answer is:
nitrate
'for fertiliser' is the definition.
(I've seen this before)
'can put up the price' is the wordplay.
'can' becomes 'tin' (both are metal containers).
'put up' shows that the letters should be reversed in order.
'the price' becomes 'rate' (I've seen this in another clue).
'tin' reversed gives 'nit'.
'nit'+'rate'='NITRATE'
(Other definitions for nitrate that I've seen before include "following 28 [SILVER]" , "Tear tin up for fertiliser" , "Nattier (anag.)" , "Fertilizer" , "salt" .)