Something dug up in the garden? (4)
I believe the answer is:
peat
But I can't explain it at all! Could you help me understand?
(Other definitions for peat that I've seen before include "Organic fuel" , "Vegetable matter in bogs, like turf" , "Tape (anag.)" , "Fuel or compost (but no longer to be used as such!)" , "Partly carbonised vegetable matter, turf" .)