Puree carrots, garlic, habanero, salt, lime juice and 1 cup water in a blender on high speed, until completely smooth and no large chunks remain. Transfer to a 1-qt. jar or a nonreactive container and cover loosely with plastic wrap and poke a few holes in the plastic to allow the hot sauce to breath. Let sit at room temperature for at least 24 hours before serving and up to 3 days.
Do Ahead: Hot sauce can be made 1 week ahead; chill after 3 days.
Cooks note: The longer this hot sauce ferments, the better it’s going to taste. If you’re new to fermenting, this is an easy recipe to start with, and you can taste the difference in flavor every day. Sure, it’s great as a fresh sauce, but by day 3, you’ll see what we mean.