Hey friend,
Thrips aren't the worst so thats good. I know they love onions, and some other outdoor plants so be mindful of carrier plants nearby.
My best success with killing them dead and gone, was a combination of first using a spinosad spray at dusk, and a dr bonners/water spray bottle.
The soap spray is perfect in health to the earth and plants and living things so be free and liberal with it. Dr Bonners is Castille soap so in my opinion safer and more effective than when I've used dawn dish soap. But any soap will do.
Good luck and do a few applications a few days apart until you see lower numbers.
Happy growing