Amazingly, onions from seed I actually do okay with. I really struggle with basil though. I wonder if climate has anything to do with it. Back in England my parents always used sets rather than starting from seed.
I'm fascinated by the toothache plant. I usually use cloves, but not sure if I could grow that here.
My grandmother used cloves. I had a toothache as a teenager and the clove burned the soft tissue in my mouth SO BAD. I had a sore for a while. It did have some pretty good antiseptic quality.
The scientific name for toothache plant is Acmella oleracea. Maybe you can find some on that side of the world. :)