Over or under watering...?

[JLee9706]

So I think one of the recent heat waves (113-117*) and smoke in the air (El Dorado Fire) had me over watering for a while. But now I can’t tell if I am i over watering or this is from previous under water from the sudden heat. This is happening to two of four of my junipers. One that is not brown is in a bonsai pot, the other is still in the nursery bucket that I cut down. I was told to wait until late winter to repot these.
Ideas in what to look out for?

 

[BrianBay9]

What kind of soil are they in? With fast draining, mostly inorganic soils it's almost impossible to over water.

 

[JLee9706]

The one in the bonsai pot is in bonsai soil mix. To be honest, I’m not sure about the others. I can assume in a good mix for the pot they are in. I picked them up at a reputable bonsai nursery. I’m going this weekend as well.

 

[BrianBay9]

The one in the bonsai pot is in bonsai soil mix. To be honest, I’m not sure about the others. I can assume in a good mix for the pot they are in. I picked them up at a reputable bonsai nursery. I’m going this weekend as well.

Take the tree along with you and get some first hand advice.

 

[sorce]

Underwatering for sure.

Lotta bullshit in ash that you'd want to keep flushed out too.

Sorce

 

[Shibui]

It is almost impossible to work out whether under or over watering from the symptoms above ground. Given your hot summer and your concern about over watering being a problem I would bet the tree has been too dry. I suspect this is often the case but people still blame over watering and the myth continues.
Best way to check is leave a wood chopstick or skewer in the soil and check it to gauge moisture content below the surface.
If in doubt more water in summer is safer. I water twice a day in summer rain, sun or smoke (and we also get plenty of that here in summer). Well drained bonsai soils are just that - well drained. Excess water does not hang around to cause problems.

Very good idea to take the trees back to get on the spot advice.