The best way to prevent weeds is to use polymeric sand, which hardens and blocks weed growth when activated with water. If you're using regular sand, you'll need to refill and compact it more often. Keeping the surface clean and free of debris can also help prevent weed seeds from settling in the joints.

Johnsongrass and crabgrass are invasive weeds that can overtake your lawn. Crabgrass is a low-growing grass most often seen in lawns, flower beds, and vegetable gardens. While you may find Johnsongrass growing in your lawn, it will also grow in pastures, crop fields, and the edge of the road. Johnsongrass is much coarser than crabgrass. If left alone, Johnsongrass can grow up to 8 feet tall. 

Whether a one-time spray treatment to control mosquitoes is enough depends on multiple factors. Often, you’ll notice a big difference after one application. However, mosquitoes are likely to return if you don't reduce attractive standing water habitats. This usually takes four to eight weeks if it’s still prime mosquito season.

If possible, you should prioritize pulling weeds up by hand. However, be sure not to use your bare hands, as many weeds are sharp or otherwise irritating when they come in contact with skin. Always don thick, protective gardening gloves to protect your hands when you pull up weeds.