Here is the full list of all 9 Reach for the Sun achievements. It takes around 2-3 hours to unlock all of the achievements on Windows.
Purchased all four plants.
Grew all possible squash parts.
Purchased all plants and all upgrades.
Purchased all garden upgrades.
Grew all possible lilac parts.
Grew all possible sunflower parts.
Grew all possible toad lily parts.
Fruited a flower without growing any extra leaves.
Beat the tutorial.