Thick scattering of seed round the end of the garden (5)
I believe the answer is:
dense
'thick' is the definition.
('dense' can be a synonym of 'thick')
'scattering of seed round the end of the garden' is the wordplay.
'scattering of' indicates anagramming the letters (I've seen this in other clues).
'round' means one lot of letters goes inside another.
'the end of' says to take the final letters.
The last letter of 'garden' is 'n'.
'seed' anagrammed gives 'dese'.
'dese' going around 'n' is 'DENSE'.
(Other definitions for dense that I've seen before include "Close-knit" , "Thick as undergrowth may be" , "Not very bright" , "Tightly packed - stupid" , "Closely packed" .)