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