Will vinegar, salt, and soap kill the grass?

Absolutely

Yes, it will.

Yes it definitely will kill grass too.

Hi Georgia,

Yes, the salt will kill anything that it gets near including the soil. If you want a natural weed killer, mix a few drops of Dawn with plain white vinegar in a spray bottle. Spray each weed at close range to keep most of if off the grass although plain white vinegar shouldn't kill the grass if you just get a small amount on it. Some recipes use the strong industrial vinegar. That will kill weeds and grass due to it's strength. I hope this helps you. Wishing you the best.

yes. Grass does not like acid. Vinegar is an acid. However, you will not be able to grow other plants there either. It will poision the soil. Salt is a deterrent, but not much of one. It never stops the grass from growing on roadsides in states like Michigan that use salt all winter.

Yes.

This article looks at all the common natural weedkillers and is really helpful

https://www.hometalk.com/diy/outdoor/pest-repeller/the-truth-about-natural-weed-killer-exposed-33053043