Chinese elm - not producing many leaves + very small leaves

[merdenoms]

Hello
I've been struggling to keep leaves on Chinese elm since the time I bought it from the Bonsai Shop.
Tree not producing many leaves plus they are small and quiet quickly they become dry and then fall. First I thought this was due to over watering the tree so I've reduced watering using chop stick technique. This at last reduced of amount of leaves getting dry and falling however I do struggle now with the size of the leaves plus there is not many of them growing. Not sure what I'm doing wrong, I've been using bonsai fertiliser now and then but this seems to not making any difference..I've attached the photo below.
I've been keeping tree in the same place partly sun /shade away from the radiator
Please help

 

[crab apple]

Another indoor tree problem, they are designed to be outdoors. Some ppl can grow trees indoors but there are some high level technical details that the averave Joe is never gonna be able to pull off.

 

[Shamino]

Another indoor tree problem, they are designed to be outdoors. Some ppl can grow trees indoors but there are some high level technical details that the averave Joe is never gonna be able to pull off.

It would help to add your zone to your profile so people can give you advice based on where you are. I live in zone 5 and have lost a couple of Chinese Elm by wintering with my Shimpaku in my garage. I'm fairly certain they died from the cold (which can get pretty nasty here in Maine.) So I bring my one remaining Elm indoors for winter (from mid Nov. to March). When indoors, it does exactly what you're seeing in yours. In spring, new buds appear and it comes back. If you scratch the bark in a small spot with your fingernail and you see green, you're good for now. However, where you live will make a difference as to handling the tree. As said above, it's basically an outdoor tree...but where you live makes all the difference.

 

[merdenoms]

It would help to add your zone to your profile so people can give you advice based on where you are. I live in zone 5 and have lost a couple of Chinese Elm by wintering with my Shimpaku in my garage. I'm fairly certain they died from the cold (which can get pretty nasty here in Maine.) So I bring my one remaining Elm indoors for winter (from mid Nov. to March). When indoors, it does exactly what you're seeing in yours. In spring, new buds appear and it comes back. If you scratch the bark in a small spot with your fingernail and you see green, you're good for now. However, where you live will make a difference as to handling the tree. As said above, it's basically an outdoor tree...but where you live makes all the difference.

Big thank you
I'm from South Wales United Kingdom. We don't get very cold winters here the worse scenario is -5 C / 23 F. Doesn't snow here.
From what I've understood Chinese Elm is an outdoor tree. Would it be ok to take tree out now or should I just leave it indoors ( away from the radiators and in the sunny place ?

 

[Shamino]

This may help...https://www.bonsainut.com/threads/chinese-elm-questions-and-wintering.41715/

 

[merdenoms]

This may help...https://www.bonsainut.com/threads/chinese-elm-questions-and-wintering.41715/

Thank you very helpful