[header] How to make weed killer [title] Start with 2 c (400 ml) of white distilled vinegar. [step] Vinegar contains acetic acid, which effectively kills weeds. Keep in mind that vinegar is non-selective and will kill any living plant it touches, not just weeds. 
White vinegar can be used alone, or you can add additional ingredients to the vinegar to make an even stronger solution. [substeps] Avoid using vinegar on or near your lawn, since it will kill the grass.