Here is the full list of all 18 Grow Up achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Bounce on a Youch 7 times without touching the ground
Discover the bull and the sheep
Discover letter block P
Complete a challenge holding a Critter
Ride two Sporchids simultaneously for 400m
Throw 100 seeds whilst gliding
Blast a Critter 100m
Take a Critter to the moon
Collect all crystals
Complete the game 100%
Plant 10 Champolines on top of each other
Complete all challenges
Unlock all Telerouters
Orbit the entire planet in BALL mode
Rescue MOM
Flower all STARPLANTS
Unlock all seeds
Visit all biomes