Hours in ground showing support (7)
I believe the answer is:
nourish
'support' is the definition.
(I've seen this before)
'hours in ground' is the wordplay.
'ground' indicates an anagram (grind the letters ).
'hours'+'in'='hoursin'
'hoursin' anagrammed gives 'NOURISH'.
'showing' is the link.
(Other definitions for nourish that I've seen before include "Provide with materials for life and growth" , "Provide with sustenance for growth" , "I rush on (anag.)" , "Nurture, sustain" , "encourage growth" .)