I have a Harsch, but I haven't made sauerkraut, yet. I have fermented mixtures of cruciferous vegetables, cabbage included, and carrots. It starts bubbling a few days after I start,(usually three) and continues for a week. I don't open the crock for three weeks. You can open it to check.

Fermentation will be slowed by cooler temperatures. Depending upon how cool your basement is, the fermentation process may not yet be "there."

If the sauerkraut is smelling good and there are no signs of mold or spoilage, it's all good. These natural processes go by their own schedule.

Carol

No, do not take the lid off and keep checking. You introduce oxygen and tempt the purification critters when you do that. Take the top of near the end of the process and taste - trust your instruction book on that.
I don't sit and watch my bubbles when I ferment, but I do know that at the right temperatures, in 13 or 21 days I will have some good stuff.
The above assumes a temperature of 65 to 72 degrees F. for the first few days and then not exceeding 80 degrees F. for the balance of the time.
It is summer so unless you are in Greenland or the Arctic, I assume your basement temp. are in warmer ranges. Foods will ferment at 45 degrees F. but I believe for kraut, that extends the usually 21 days to 6 months or so.
Hope this helps.
Jim in So Calif