The Root of the Problem is an achievement that requires the player to harvest a limpwurt root from the Farming patch in the Western Ruins in the Wilderness.
Add a supercompost to the Farming patch to decrease the chances of the limpwurt plant from getting diseased and dying. Then add the limpwurt root seed to the patch. If a limpwurt plant was already planted prior to the Wilderness achievements update, the limpwurt plant can be simply be picked to complete the achievement.