Japanese black pine advice needed

[Shibui]

According the information of the shop this soil has "additional micronutrients fertilizers in small concentration". Does that mean I don't need to fertilize during this year at all? I've bought biogold original couple of years ago and I was thinking to use it when needed.

Commercial potting soil has a minimum amount of fertilizer added because fert costs money. The nutrients in the soil will usually just feed the plants for 3 months. Definitely add more fertilizer during the growing season to get better health and better growth rates.

Do not worry about long needles on pines as they grow. Needles only live for 3 years so will be well gone by the time this seedling gets to be a bonsai. When the pine is developed more we change to a different pruning regime and old needles are removed each year so in real bonsai needles are only ever 1 year old. The pine management techniques aim to get the trees to grow only short needles but all that is way in the future for this little tree. For now you need to concentrate on growing a thicker trunk but still retain some low shoots which will eventually be your actual bonsai branches and canopy. As mentioned you will find some good advice and inspiration in the six year pine contest threads.

 

[Juzzi77]

Thank you all for advice and help so far.

So.. Here we go again. This time I forgot my pines in a closed greenhouse. So they received excessive heat for approximately two hours. Temperature was something like 40°C - 50°C. (104F - 122F).

Looks like luckily only one JBP has some grey / brown needles.
I suspect this damage is caused by heat. Or can it be something else? It is there anything I can do for it?
Can it heal damaged needles or does it matter if I remove them?
From now on I planned to keep it away from high temperatures and just mist it daily..

 

[Deep Sea Diver]

Not sure I see anything to be concerned about…. am I missing something?
Cheers
DSD sends

 

[Shibui]

Pines can cope with 40-50 C. We routinely have ambient temps above 40C and my pines are all in full sun all day all summer.
You have some scorched ends on some leaves. Nothing to worry about.
The brown ends could be from heat but more likely they did not have enough water to cope with that heat.
Damaged parts of needles will not recover but the parts that are still green will continue to provide valuable food for the seedling. I would not even bother to cut any but if the brown ends distresses you you can cut them off without hurting the plant.

Misting may not be the best for a pine. Just water properly when the soil is starting to dry.