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.

It usually takes between two weeks and a month for weeds to fully die off after you spray them with herbicide, but they will start to wilt within the first week. Different weed sprays produce different results, with some working more quickly and effectively than others. Similarly, some weeds are killed more easily than others. Consult your weed removal pro for an exact timeline based on their weed removal method.

There are organic herbicide options that will kill grass but not flowers, including white vinegar or a dish soap solution. Commercial selective herbicides can also target grass over other plants, but read the instructions carefully to avoid damaging your garden. Herbicides that kill grass but not flowers usually include ingredients like clethodim and sethoxydim. Otherwise, your best bet will be to weed by hand.

Crabgrass is very resilient, and homemade solutions like vinegar may not be strong enough. Typically, hand-weeding is the most effective option that doesn’t involve harmful chemicals. You can use corn-meal gluten as a natural pre-emergent herbicide, but it’s not as effective as chemical weed killers.