Cactus / caput-medusae seedlings

Germination of caput-medusae is easy and seedling grafting also same.
I am not sure why but own-rooted seedlings are picky.
I can collect seeds from my grafted plants and can sow a lot of seeds.
I lost a lot of seedlings so far. It may dislike repotting.

I repotted 100 seedlings this morning.