Weeds are pretty hardy and fast-growing plants. They can turn any lawn into a real mess in a short time. The same goes for crabgrass, which can displace all other beneficial grasses on your yard over time. If you see an adult plant on your lawn, you should immediately use the best crabgrass killer to stop it from multiplying. It can produce about 150000 seeds in just one season. Once weeds germinate and start to grow, no amount of pre-emergents or preventers will destroy them. That is why you need a killer. Fortunately, crabgrass is annual, so your chances of eradicating it are high.