Hi guys I just bought a cotoneaster bonsai and within a week the leaves on the lowest part of the tree is yellowing some falling off. No brown leaves.
I have two 50W led grow lamp turned on for 8 hours at night. I am watching the soil moisture very closely each day.
Is this normal at all that the leaves are yellowing only at the lowest level?
Any ideas if there are some problems?

.. let me get this straight: you keep your tree indoors and have lights on it at night?...
Without a picture it is very hard to say anything

The problem could be that it is indoors

Is it bad to have light on at night?

The tree is in my mini zen garden, the pot has holes so water can exit.
I have some pictures

It is bad to have it inside.

While the sun shines, plants perform photosynthesis. In this process, the plants convert sunlight, water and carbon dioxide into stored energy in the form of long chains of sugar, called starch. At night, the plants burn this stored starch to fuel continued growth.

Keeping a tree in constant light makes them store a lot of starch, but give them no time for growth. This is very stressful for the tree.

and growlights are not a substitute for sunshine

Tropfrog wrote: While the sun shines, plants perform photosynthesis. In this process, the plants convert sunlight, water and carbon dioxide into stored energy in the form of long chains of sugar, called starch. At night, the plants burn this stored starch to fuel continued growth.

If you copy paste from other websites, please include the source. www.seeker.com/plants-do-math-to-survive...ight-1767604177.html

Thanks for your input everyone, I will try to adjust the light schedule. The whole point of me getting the bonsai is to keep it in my mini zen garden indoors. I know some people have been able to keep their bonsai healthy indoors. I'm just hoping that part of the reason it has some yellowing leaves is that it is reacting to the change in environment and will adapt with proper grow light schedule and water. I will probably try some liquid fertilizer too.

Wxc821 wrote: I know some people have been able to keep their bonsai healthy indoors. I'm just hoping that part of the reason it has some yellowing leaves is that it is reacting to the change in environment and will adapt with proper grow light schedule and water. I will probably try some liquid fertilizer too.

Sorry. But no. You will not be able to keep it healthy indoors.Bonsai is not a species. This plant species does not stay alive indoors. Ficus are the most suitable plant family to keep indoors and with added light might do OK.