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