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