The jade plant pictured spent most if its life indoors. Then, at the start of the pandemic, it moved to a house where it could be placed outside during summer day, rotating on a daily basis. It thrived and grew thick, healthy leaves everywhere.
In winter, it has been indoors where it receives from overhead bright direct light through a skylight (that is tinted but not colored) and receives lots of indirect light through clear glass all day. (That is, the room is bright with natural light.)
Earlier in the winter, the plant started dropping interior leaves, those shaded by other leaves (and I posted about this and received helpful feedback). Because the outer leaves were, and are, healthy, or seem so, I didn't worry about this. But now the interior loss has become enormous. It seems that almost any leaf even slightly in the shadow of another leaf has dropped, more than half of the total leaves, I'd estimate. Now I'm worried that the plant is dying.
It has been colder in the house during the winter than in the summer or fall, particularly in the last week when the furnace failed. But the temperature never reached freezing and so I doubt that's the cause.
My watering routine has not changed: soaking the soil once every two to three weeks. The pot is clay (and although it looks deep, most of the bottom of it is filled with rocks and shards of the previous clay pot.) I have stopped fertilizing for the winter, but wonder whether I should start again even before spring.
Finally, the grow lights in the pictures are new, just put there a few days ago in the hope of dealing with leaf-drop problem and so could not have caused it. And even though the problem has gotten worse in the days since the lights were put on, I can't imagine that they are the problem as they are set for only 8 hours a day (during daylight outdoors).
Have been growing this plant for a decade and so would be sad to lose it. So, any advice would be welcome. Such as should I water more? Less? Use fertilizer even though it's winter? Get rid of the lights? Move the plant to another window (which would be inconvenient but possible.) Also, assuming the plant is not dying, will the scars where the leaves have fallen (some pictured below) grow stems in spring and summer? That would be a great outcome, but I don't know. Thanks in advance.
