Hi all first time posting here,

I recently bought a Japanese elm bonsai tree from B&Q, at the moment I haven’t reported it.

I noticed the tree is dropping some leaves, at first the ones dropping were yellow and some were crispy so assumed I was under watering.

But now green leaves are dropping, I know some bonsáis she’d leaves in the winter due to temp changes.

I have also found these really small red bug/spider looking things in its soil, I think their spider mites but they haven’t made their way to the leaves they are just in the soil, there’s no webs either.

What can I do to get ride of them? Is isopropyl alcohol (diluted) safe to put on the roots, or maybe dish sop diluted?

Little red bugs do not say much. They are definitely not spider mites as they live on the leafs, not in the soil. I have a hunch they are soil mites. Small arachnoids that live on decaying matters. Not a threat to your tree as long as the general care keeps the tree healthy. Quite the opposite actually. They turn organic matters into fertilizer awailable to the tree.

Oh yes...Elms are decidious. Loosing leafs in winter is natural. Not loosing leafs may be a serious issue.