Here is the full list of all 21 Grass Cutter trophies - there are 4 bronze, 8 silver, 8 gold and 1 platinum.
Good job! Completed all tasks!
Drive by 10 times on the sand
Break 100 barriers
Eliminate multiple monsters in less than 1 second
Gather up energy when there is less than 5% left
Scare the cats 15 times
Eliminate robot
Face the monsters 50 times
Scare the dogs 20 times
Make the first purchase
Disable 50 monsters
Use a bomb
Eliminate quadcopter
Cut 1000 squares with grass
Get wet in the rain
Dive into the water 20 times
25 times, purchase 15% of the energy
Scare the birds 50 times
Take a mud bath 20 times
Immerse the first box
Complete the first level