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!
25 times, purchase 15% of the energy
Face the monsters 50 times
Take a mud bath 20 times
Break 100 barriers
Drive by 10 times on the sand
Dive into the water 20 times
Disable 50 monsters
Scare the dogs 20 times
Scare the cats 15 times
Eliminate robot
Use a bomb
Eliminate multiple monsters in less than 1 second
Scare the birds 50 times
Gather up energy when there is less than 5% left
Make the first purchase
Cut 1000 squares with grass
Eliminate quadcopter
Get wet in the rain
Immerse the first box
Complete the first level