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