I usually do crushed up cookies and brown sugar or graham crackers for dirt and sand. What would you all use? i as thinking of mixing a tad bit of red terra cotta color to gram crackers??

coconut dyed redish?

Chopped up Strawberry laces?

oh yes maybe ill do the coconut! :) thanks great idea! Strawberry laces are super hard to find around here lol, thanks a bunch!! 

Shredded colored chocolate shavings? Maybe melt down some white chocolate that's been colored and cool into a chunk and then use a peeler to shave it into the size pieces you want. Never tried it but sounds like it might work. Good luck.

You could roll out some red mulch colored fondant very thin and let it sit over night to air dry. Then with a pastry cutter cut the now fairly dry fondant in very thin strips and then run the cutter through those to shred it. I made some hay in this manner and it was very effective. HTH

 Make some cookies the color you need.  Red velvet cookies, or sugar cookies tinted the right color.  After baking, crumble them up like dirt.  you could also mix in some crushed chocolate wafers or graham cracker crumbs for interest.  Most dirt isn't perfectly uniform in color.