Garden center bagful (4)
I believe the answer is:
soil
'garden center bagful' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for soil that I've seen before include "Top layer of the surface of the earth" , "Loose upper layer of earth" , "In which plants grow" , "Dirty - dirt" , "Sully with earth" .)