Thick scattering of seed round the end of the garden (5)
I believe the answer is:
Here is my best explanation:
'thick' is the definition.
('dense' can be a synonym of 'thick')
'scattering of seed round the end of the garden' is the subsidiary indication.
'scattering of' is an anagram indicator (I've seen this in other clues).
'round' means one lot of letters goes inside another.
'the end of' indicates one should take the final letters.
The last letter of 'garden' is 'n'.
'seed' is an anagram of 'dese'.
'dese' enclosing 'n' is 'dense'.
(Other definitions for dense that I've seen before include "Close - compact - stupid", "Not very bright", "Slow-witted", "Thick as undergrowth may be", "Crowded together", "Closely-spaced", "Thick, compact or crowded", "Closely packed", "Thick, impenetrable" and "Tightly packed - stupid".)