This is in Denver in an amended clay soil. We have had several weeks of 100+ temps daily. The bok choy have not grown beyond about 2 inches tall for the past 3-4 weeks. They aren't dying but also not growing stronger. Solutions?
Bok Choy Seedlings Do Not Grow Beyond 2nd Set of Leaves
Certified GKH Gardening Expert
It is the heat. They will likely bolt. They simply cannot grow properly in those kinds of temperatures. You can try to keep their roots cool, and that may help. But mostly likely, even this will not work in that heat.
In the future, try growing bok choy only in the spring or fall. Over summer, they cannot take the heat.