Good players make bloomers too (5)
I believe the answer is:
'good players' is the definition.
'seeds' can be an answer for 'players' (seed is a kind of player). I am unsure of the 'good' bit.
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for seeds that I've seen before include "nuts" , "Pips" , "Initiates the growth of" , "Small hard fruit" , "Favoured entrants in a knock-out competition" .)