Small garden tool? It’s over a foot (4)
I believe the answer is:
shoe
'it's over a foot' is the definition.
(shoes are worn on feet)
'small garden tool?' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'garden tool?' becomes 'hoe' (tool used when gardening).
's'+'hoe'='SHOE'
(Other definitions for shoe that I've seen before include "Sandal or brogue?" , "pump, say" , "One of a pair to wear" , "Oxford, say" , "Plate nailed to underside of horse's hoof" .)