I'm concerned about our Picea glauca var. albertiana 'Conica' that we keep on the balcony in a pot. We bought it sometime in spring this year and had it in the pot shown below for some time now. Throughout summer it looked good and grew several layers of new needles, however since the end of summer we've noticed that more and more brown needles occur at the outer layer rather than on the inside.
I found an answer that describes a similar sympton in which the user states
Overwatering results in root death. Then, with roots unable to move water, the top shows the same symptoms as drought.
While from probing the soil with my finger I didn't get the impression that there is excessive moisture on the bottom, it might just be that it's already too much for this tree. As we've kept it near the edge of our balcony, I have the suspicion that it got too much rain water that wasn't able to drain quick enough in this arrangement.
Is root death the correct diagnosis here or are there other causes I should look into?
Can this spruce be saved? If so, how should we intervene?