Sinking spades, kill plants (4)
I believe the answer is:
'kill plants' is the definition.
The answer and definition can be both to do with contact as well as being verbs in their -s form.
Perhaps you can see an association between them that I don't see?
'sinking spades' is the wordplay.
I cannot quite understand how this works, but
'spades' could be 's' (abbreviation in card games) and 's' is located in the answer.
The remaining letters 'lay' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for lays that I've seen before include "Places (bets?)" , "How Pertelote produces" , "Arranges" , "Minstrel's melodies" , "Produces an egg" .)