Get matched with top weed maintenance pros in Wheatland, CA

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.

No, it's not really possible to completely prevent weed growth. Weeds are incredibly resilient—all they usually need is a tiny bit of dirt to sprout, so their eventual appearance is pretty much inevitable. However, you can definitely keep them at bay by getting rid of weeds as soon as you notice them. The longer you let them sit and grow roots, the more they'll spread.

Yes, Johnsongrass is a hard weed to kill. It has the ability to grow fast and spread even quicker, so it requires a detailed plan and thorough application to eliminate it. The best plan of action is to kill Johnsongrass while the weed is establishing itself by hiring a lawn care professional or following the steps above. 

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.