Last year I began an experiment of growing some of my own Scots pine material for bonsai at home. After 1 year of growing them the trunks are now 15mm thick and the roots are well established. The needle length has at least doubled.
After 1 year they are too stiff to bend so if you want movement on the trunks then they should be wired and shaped in the first year. I see everything over 20cm on these as sacrifice and want it to grow as quickly as possibly. One of the lower shoots will be trained as the actual trunk - I have plenty of choices there and I am in no rush.
The pots are standard hydroponic issue 6.5 litre pots.
They took a long time to take root and be stable in their new pots due to the small cell root system they had when I got them. The wind was a real problem last year - they need to be sheltered and staked. Some had substantial disturbance of their roots by blowing over and having the pots falling over. All 4 are now free standing and stable through the winter outdoors.
They went through most of the year on organic fertilisers. As the temperatures warm up they will go onto them again this year.
Where possible I try to use rain water on them - but quite often I am pressed for time so it's tap water. They don't seem to be bothered at all by the hard London tap water. I think Beech trees may not like the hard water much - something I am trying to understand.
They are of quite variable vigour. Some are extremely vigorous - especially the ones grown in the coco coir. This one seems to have budded from every bud on it from the ground up.
I am very pleased that none of my pines have any flowers this year. This means that they are not starving or stressed. So many Scots I see at bonsai shows are covered in flowers that it makes me doubt myself. Not sure how they deal with the bald patches.
On the apex I had so many large candles that I have already had to remove several - and more will need to be removed. I will work through each tree over the coming weeks and remove a lot of buds and candles as there are far too many at the moment.
Here is how they started 1 year ago with a tiny cell grown root system.