Place to plant hit in stomach — it hurts to fight (6,3)
I believe the answer is:
window box
'place to plant' is the definition.
(place where plants may be planted)
'hit in stomach it hurts to fight' is the wordplay.
'hit in stomach' becomes 'wind'.
'it hurts' becomes 'ow' (expression of pain).
'to fight' becomes 'box' (boxing is a kind of fighting).
'wind'+'ow'+'box'='WINDOW-BOX'
(Other definitions for window box that I've seen before include "where flowers may be found" , "Narrow container for plants" , "Plant container on sill" .)