Chop or shred the cabbage. Sprinkle with salt.
Work the cabbage with clean hands or masher until there is plenty of liquid and the cabbage is a bit mushy. Takes about 10 minutes.
If using whey, add the whey and mix well.
Stuff the cabbage into the fermenting container, pressing the cabbage underneath the liquid. If necessary, add a bit of water to completely cover cabbage.
Culture for 3 to 10 days at room temperature.