Know of any natural herbicides to prevent weeds from growing on a walkway?

Boiling water kills weeds on walkways. So does vinegar.

You may have to apply it several times, but it'll work.

If salt runs off into garden areas, it'll have long-lasting toxic effects on anything you may want to grow there in the future.

Your local garden centre will stock what's legal in your area.

I use boiling water to kill the weeds on my paths.

there are a few extracts you can get from plants such as black walnut, sunflowers, sagebrush and spotted knapweed. however im not exactly sure how easy it is to do yourself

and a side note

garlic and onion...where did you get that one from....

Salt works well.

garlic and onion