1. Place the chopped cabbage, onion and daikon in a large bowl. Add sea salt and massage the vegetables with clean hands by giving them gentle squeezes for about one minute. Set aside for 30 minutes.
2. Add the rest of the ingredients and mix well.
3. Pack everything, including the liquid that has released from the cabbage, into a quart-size, wide-mouth mason jar.
4. Using a wooden spoon or rolling pin, pound down the mixture to help release more liquid. Firmly pack down the cabbage mixture until it's level with the shoulder of the jar, and that there is one inch (2.5 cm) of brine above the top of the vegetables.
5. Place Kraut Source onto the jar. Allow to ferment for 5 – 14 days in a cool spot, away from direct sunlight. Check every few days that there is water in the moat, and top off as needed.
6. Replace Kraut Source with the standard mason jar lid and ring. Transfer to the refrigerator.
Note: As Napa cabbage releases a lot of water, keep an eye on your kimchi during the first 24 - 48 hours. There should be about one inch (2.5 cm) of liquid above the top of the vegetables, so pour off excess if it looks like it will over flow.
For a traditional kimchi recipe using gochugaru, or Korean red pepper flakes, please visit this page.