Seed leaving red stain spoiled blue tent (5,3)
I believe the answer is:
betel nut
'seed' is the definition.
(betel nut is a kind of seed)
'spoiled blue tent' is the wordplay.
'spoiled' is an anagram indicator.
'blue'+'tent'='bluetent'
'bluetent' with letters rearranged gives 'BETEL-NUT'.
'leaving red stain' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for betel nut that I've seen before include "Seed of a palm chewed (with its leaves) as a narcotic" , "that's found on palm" , "supplies a narcotic" , "stimulant" .)