Lawn material (3)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">lawn material</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for sod that I've seen before include "A lump of turf (3)" , "Piece of peat or grass" , "A lulmp of turf" , "Surface layer of ground with grass roots" , "A piece of sward." .)