- Cut the radish into 2.5cm (1 inch) by 2.5cm squares, each about 3mm (eigth-of-an-inch) thick.
- Cut the cabbage leaves into similar 2.5cm by 2.5cm squares.
- Wash the cabbage leaves and radishes together, drain, then sprinkle thoroughly with 3 tablespoons of salt. Let sit for about 30 minutes.
- Cut the green onions (and watercress if you are adding it) so their length is about the same 2.5cm as the cabbage leaves and radishes.
- Mix the green onion, chopped garlic, chopped ginger, and red pepper powder.
- Thoroughly rinse the cabbage leaves and radishes.
- Now thoroughly mix the radishes and cabbage leaves with the seasoning mixture from Step 5. Let sit for 30 minutes, then place into a storage container.
- Heat the water until lukewarm, then mix it with the rest of the salt (2 tablespoons).
- Pour the salty water into the storage container with the rest of the kimchi. Store in a cool place for a day or two until fermented and ready.
- If you are adding the watercress, don't add it until a day or so into the fermentation - this will help keep it green and crunchy.