1. Preparation
Slice 1 medium Napa cabbage in half lengthwise and then into quarters. Rinse it thoroughly under cold water and drain.
Sprinkle 1/2 cup of coarse sea salt over the cabbage, making sure to distribute it evenly between the layers.
Let the salted cabbage sit for 1-2 hours, tossing it occasionally to ensure even salting.
While the cabbage is resting, prepare the other ingredients: peel and julienne 1 medium Korean radish and slice 3 green onions into 1-inch pieces.
In a mixing bowl, combine 1 tablespoon of grated ginger, 4 cloves of minced garlic, 2 tablespoons of sugar, and 1/2 cup of Korean red pepper flakes (gochugaru).
Add 1/4 cup of fish sauce to the mixing bowl and stir until well combined to form the kimchi paste.
2. Mixing
After the cabbage has salted for a couple of hours, rinse it thoroughly under cold water to remove the excess salt and drain well.
In a large mixing bowl, combine the drained cabbage, julienned radish, and green onions.
Add the kimchi paste to the bowl and use your hands (wearing gloves to avoid skin irritation) to mix everything together until all the vegetables are coated with the paste.
3. Fermentation
Pack the kimchi mixture tightly into a clean glass jar, pressing down to remove air bubbles.
Leave some space at the top of the jar to allow for expansion during fermentation.
Seal the jar with a lid and leave it at room temperature for 1-3 days, depending on your desired level of fermentation.
Check daily; if you see bubbles, it’s fermenting. Once it reaches your preferred taste, transfer the jar to the refrigerator.