The seedling overwintered for the first time, and it was not too bad when spring came. But accidentally, I fell the pot down, and the seedling completely thrown out from the pot, also a few petioles fell off.
However, the root was long and healthy enough, thus I put the plant back with more soil packed more firmly, then kept it in the partial shade. I also kept watering minimum since it was in the monsoon season raining everyday, less sun shine and the humidity was high.
Curry leaf plant is quite strong and solid once good root is established. The seedling is now 15cm tall with new petioles.
Therefore, even though you might find your seedling gets harmful insects or got some accident like I had. As long as the root is healthy, there is good possibility to revive the plant as long as you pay some attention not to over water and over dose the fertilizer.
During hot summer like right now in Tokyo, good watering is also important.
It is best to hold the pot when it is dry and just learn how heavy it is by feel. When you water, water it until excess water runs out from the bottom of the pot.