Here is the full list of all 13 TumbleSeed achievements.
Beat the Forest Mountain
Reach the Desert Biome
Reach the Jungle Biome
Reach the Forest Biome
Reach the Snow Biome
Plant every type of seed at least once
Complete all quests
Cleanse the mountain
Cleanse the mountain in under 15 minutes
Save the mountain
Beat the Jungle Mountain
Beat the Desert Mountain
Beat the Snow Mountain