Here is the full list of all 31 Garden In! achievements.
Pet a plant in need of love
Unlock a new room
Unlock a new seed
Disinfest an infested plant
Water a dry plant
Complete a research
Grow your first plant
Set two seeds into a hybridization vase
Open the Herbarium
Delete a plant
Move a plant in a different room
Delete an infested plant
Delete a dry plant
Change the color palette of a room
Unlock all ground plants
Unlock all air plants
Unlock all water plants
Take a picture
Pet 500 plants in need of love
Unlock 10 seeds
Unlock all vases
Unlock a camera filter
Water 500 dry plants
Disinfest 500 infested plants
Place 10 hybridization vases in the laboratory
Unlock all the rooms
Complete all the researches
Have 50 grown plants in the balcony
Place 30 copies of the same plant in the same room
Grow all 36 plants in the same room
Congratulations, you have unlocked all the achievements!