I have a gravel driveway that has grass growing through it and it looks pretty bad now. I am hesitant to try a commercially available weedkiller as I don't want it to eventually seep down into my well water (don't know if that's a possibility but why take the chance?). So I'm wondering, does anyone have an idea for a homemade weed killer that will work on grass? And no, I don't want to pour oil or gas on it... lol

vinegar WORKS

Just straight vinegar? I'll try it. Thanks

I buy it by the gallon and put it in a spray bottle.

Almost all commercial weed killers only react with chlorophyl bearing plants. They will decompose with soil contact. That's why you can see new weeds popping up even if you spray. Look at the ingredieent list and the dilution ratio, mostly water. Unless you are using agent orange, you will not have well issues.