Japanese black pine needle browning

[roshanrosareo]

I had potted this seedling in the pot last year in a bonsai soil(alp). It has been growing well in spring and summer. In fall, I started noticing few needles browning in the lower branch and the bud not so aggressive. I have seen the diagnosis chart and couldn't find the exact issue. I suspect the browning could be due to either over fertilizing or under or over watering related, or if got burnt due to under watering. It is currently dormant. Can you please help with the issue related to it? I live in zone 5 illinois. I will plan to repot in early spring anyway, but would like to rectify the issue.

 

[Shibui]

The photos are not clear enough for an accurate diagnosis.
Also very difficult to differentiate between under and over watering as the physical symptoms are virtually the same - dehydration of living foliage. The only real difference is seen in the roots.
The fact that this showed up in fall would tend to indicate overwatering as a possibility, especially if you had not reduced water as temps and rain changed.
I doubt that fert will be the problem.

There's probably little you can do now but try to keep it on the drier side of damp until you can repot.

 

[Scorpius]

Drill some holes in the side of the pot to allow for some air exchange to the roots.

 

[Potawatomi13]

Where tree kept Summer, now also? Composition of substrate? Drained freely? How often watered? Please add location to profile for better help.

 

[Bonsai Nut]

I had potted this seedling in the pot last year in a bonsai soil(alp).

Though the seedling doesn't look bad to me, I am curious about the soil. It looks like 100% pine bark, or similar... and it looks unnaturally dark. It doesn't look like any bonsai soil that I am familiar with.

 

[Maiden69]

Though the seedling doesn't look bad to me, I am curious about the soil. It looks like 100% pine bark, or similar... and it looks unnaturally dark. It doesn't look like any bonsai soil that I am familiar with.

Looks like the black hardwood mulch I use to cover the side of the pots in winter and use for around the drip line of my house trees. Just as Shibui said, difficult to say if over or under water...