Grate the carrots in a food processor or by hand. Add them to a big bowl.
Add in the sea salt and grated ginger.
Using your hands, massage the sea salt and ginger into the carrots for about 5 minutes. Making sure to evenly distribute the salt and ginger.
Let sit for 10 minutes. The salt will draw out the liquid from the carrots making them limp and wet.
Pack the carrots tightly into a mason jar with your hands or use a vegetable stomper. The carrots will become submerged under the liquid. Continue packing in the carrots until they are an inch from the top of the jar. You can place a weight on top to keep them submerged under the brine or push them back down under the brine daily. Seal loosely with a lid so gases from fermentation can escape.
Let them sit in a dark place on your counter for 4-7 days. Make sure they are not in direct sunlight.
If any mold or scrum appears on the top of the carrots just scrape it off. This is common and the carrots under the brine are still good.
Taste them after 4 days. When they are tangy and you like the taste then put them in the fridge. They will store safely in the fridge for several weeks.
Notes
You can use pickling weights like these or a rock to keep the carrots submerged under the brine.
Recipe by Fermented Food Lab at https://www.fermentedfoodlab.com/raw-pickled-ginger-carrots/