Use the TROWEL in the dirt; use the SHARP NUTSHELL on the bag and take WAGON LOCK PIECE (A).
Place the WAGON LOCK PIECE in the slot (B) to activate a puzzle.
Slide the red lock to the exit.
Move the blocks in the direction of the arrows in this order: Red, Yellow, Green, Purple, and White (1-4).
Play the HOP.
You receive the FERTILIZER SACK (C).
Return to the Castle Ruins.