The best defense against crabgrass is to maintain a healthy and dense turf. Ensure that your lawn is mowed to the proper height (usually around 3-4 inches) to promote thick grass and shade the soil, which helps prevent crabgrass from germinating. Regularly feeding your lawn and adequate watering also supports healthy grass growth, making it more competitive against weeds like crabgrass
Environmental friendly solutions:
1) If the infestation is small, hand pulling can be effective. This should be done when the soil is moist to make it easier to remove the roots. Make sure to dispose of the pulled plants properly to prevent reseeding
2) pour boiling water on patch (will also kill good grass)
3) spray with vinegar (not cooking strength--need 20% - may need to spray several times
4) Mulching: For garden areas, applying a 2-3 inch layer of mulch can suppress germinating weed seeds, including crabgrass, by blocking sunlight.

Chemical solutions (Must follow the instructions on the label) 5) Applying a preemergent herbicide before the crabgrass seeds germinate is one of the most effective chemical controls. It's best to apply this in early spring when soil temperatures consistently reach about 55°F for several days.
or, use a post-emergent herbicide (not necessarily safe for children or pets). For example, Image All-in-One Lawn Weed Killer; Image Herbicide; Scotts Spot-Weed Control for Lawns.
6) If crabgrass is already established, a postemergent herbicide can help control it. Apply these products to young crabgrass plants before they mature. It's essential to follow label instructions carefully since some herbicides can damage desired grass species
To prevent crabgrass and other other weeds:
1) Mow you lawn at the proper height for your grass type
2) Feed regularly (e.g., 6-2-4) or put down thin layer of compost
3) Deep water your lawn (shallow, frequent watering encourages shallow root growth which allows for weed growth.
It's vital to monitor your lawn regularly for new crabgrass growth and take action promptly. Correct identification and timely management can significantly reduce crabgrass populations over time.
Hope this helps