Is this normal? Vachellia tortillis

[Marowak]

I have been growing these for 4 months and now I moved them inside as it is getting in The low 5 degrees celsius at night they are in an ikea greenhouse with led lights from 9-10 am to 18-19pm . I read that They can get a shock is this what is happening The one with The most mature wood is looking The worse. No idea what to do or if its normal.

 

[fredman]

I don't know much about growing them under lights. They do well in an unheated garage during winter.
The most matured one might just be sensing the autumn first...hence getting ready to shed its leaves. Only time will tell though.
They are very hardy and drought resistant. They should be kept on the drier side...especially during dormancy. Good drainage is essential.
They do tolerate cold well. Where they naturally grow, the temp can go down to freezing at night. I remember they can tolerate frost once they are a few years old.

 

[dbonsaiw]

I’m growing vachelia caven and just brought mine in under lights. Some needles will brown and fall off, but the tree acclimates. Mine are otherwise in leaf all year long.