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