Add salt for some time (6)
I believe the answer is:
season
I believe this is a double definition.
'add salt' is the first definition.
(I've seen this before)
'some time' is the second definition.
(I've seen this before)
'for' is the link.
(Other definitions for season that I've seen before include "Flavour food with salt, pepper etc" , "instruction in recipe" , "spring, perhaps" , "One of four periods" , "such as 'Summertime'" .)