Q.Curry leaf plant
I bought 3 curry leaf plants in November 2917. They were doing well until recently – in fact started having a lot of fresh growth from around February. Then a couple of weeks ago one of the plants started dropping – it has lost all the new growth and most of its leaves. The other two plants are showing signs of the same thing happening. All three plants have been on a table by a sunny patio door. I have attached photos of all three. Please advise.

Certified GKH Gardening Expert
I believe this will need a larger container pretty soon. In such a small container, it is likely to run out of nutrients very quickly, which would produce the symptoms that are happening now.
I would repot into a larger pot, and add compost to the soil. This will feed the plant. When you start noticing signs of this happening again, just add more compost to the top, some dolomitic lime, and worm castings if you would like. This will boost it up again.
Container gardening can be tedious, but it has its obvious advantages as well. This article will give you more information on the care of these: https://www.gardeningknowhow.com/edible/herbs/curry/growing-curry-leaf.htm