Cut the cabbage in half, lengthwise. Cut them again lengthwise. Cut them once again lengthwise. Cut the cabbage into big bite-size ( they will shrink after the salting process). Place the cabbage in a large bowl and soak them under cold water. 

In another large bowl, take some of the cabbage out of the water (No need to drain them well) and sprinkle about a couple of tablespoons of Korean coarse sea salt on top. Repeat the process until all the cabbages are sprinkled with salt. Pour about 1 cup of water on top. Let the cabbage salt for about 90 minutes. 

About after 90 minutes, mix the cabbage around. It is perfectly normal to see a large amount of water collected at the bottom of the bowl. Try to place the cabbage that was soaked under the water to the top and bring cabbages they were on top to be submerged on the bottom. This ensures all the cabbage pieces to be salted evenly. Continue to salt the cabbage for additional 45-60 minutes. 

Cut the daikon into small pieces. In a medium-size bowl and pour about 1/2 cup of the salted water that was collected on the bottom of the cabbage. Soak the daikon for 15-20 minutes. Drain the daikon and set it aside.

Prepare your kimchi sauce. Boil about a cup of water. Once the water comes to a boil, turn off the heat and place the dried kelp/kombu in the water. Let it steep for 10 min. Take the kelp out of the water and add 2 tablespoons of flour and whisk until you no longer see the clumps of flour. Turn on the heat to medium and let it simmer for a couple of minutes until it thickens. After a couple of minutes, turn off the heat and let this mixture comes to room temperature. 

Either using an immersion blender or regular blender, blend the garlic cloves, onion, apple, and flour mixture until smooth. Transfer this mixture to a bowl and mix together Korean red pepper flakes, sugar, and 1-2 tablespoon of Korean coarse sea salt. Set aside.

Grab a piece of salted cabbage (the white stem part of the cabbage) and try to bend the piece. If the piece bends without breaking, it is ready. Rinse the cabbage under cold water a couple of times. Squeeze out the water from the cabbage and transfer them into a large bowl. 

Gently toss together (don’t be rough with the vegetables) your daikon, cabbage, carrots, and half of the sauce until all the veggies are well coated with kimchi sauce. Taste your kimchi and adjust the sauce. If you want it to be a little spicier, add more. 

Transfer the kimchi into a big container. You can enjoy the kimchi right away. If you want your kimchi to be sour, let your kimchi sit on the countertop for a day or two until it ferments to your liking. Keep in the fridge afterward.