Adding vinegar to your lawn increases the acidity of the area, which can kill quack grass present above the ground. However, putting vinegar in your yard will also kill the grass. Unfortunately, the below-ground quack grass rhizomes remain very much alive in the presence of vinegar and will soon sprout again.

You should add 1 to 4 inches of mulch, depending on your garden type and needs. Keep in mind that no amount of mulch can completely prevent weeds, but a heavier coverage (closer to 4 inches) can suppress weeds enough that you are only seeing them sprout every few weeks. Finer mulch prevents weeds more effectively than large mulch, so if you’re using mulched leaves or shredded bark, 1 to 2 inches will likely suffice, while 3 to 4 inches is best for larger mulch, like bark chips or straw.

If you spray a DIY vinegar solution that contains high salt, it can disrupt the soil's structure and make it difficult for plants to grow. That's why it's vital to avoid spraying vinegar solution on areas where you are trying to grow plants and flowers. When using a mix of vinegar and soap, some say you can plant a few days after the vinegar dries. 

Yellow patches, poor growth, or widespread weeds indicate a need for treatment. Soil testing can confirm nutritional deficiencies that require intervention.