My ornamental Kumquat is losing its leaves

Question

It’s just been put into the green house after wintering indoors

Answer 1

There can be several reasons for leaf drop, but this is likely do to a change in environment. Make sure you are gradually making the transition to full sun. Under a shade cloth for the hotest part of the day.

https://www.gardeningknowhow.com/edible/fruits/citrus/leaves-falling-off-citrus-tree.htm