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