Bulbs
Flower Basics
Flower Beds & Specialty Gardens
Flower Garden
Garden Furniture
Garden Gnomes
Garden Seeds
Garden Sheds
Garden Statues
Garden Tools & Supplies
Gardening Basics
Green & Organic
Groundcovers & Vines
Growing Annuals
Growing Basil
Growing Beans
Growing Berries
Growing Blueberries
Growing Cactus
Growing Corn
Growing Cotton
Growing Edibles
Growing Flowers
Growing Garlic
Growing Grapes
Growing Grass
Growing Herbs
Growing Jasmine
Growing Mint
Growing Mushrooms
Orchids
Growing Peanuts
Growing Perennials
Growing Plants
Growing Rosemary
Growing Roses
Growing Strawberries
Growing Sunflowers
Growing Thyme
Growing Tomatoes
Growing Tulips
Growing Vegetables
Herb Basics
Herb Garden
Indoor Growing
Landscaping Basics
Landscaping Patios
Landscaping Plants
Landscaping Shrubs
Landscaping Trees
Landscaping Walks & Pathways
Lawn Basics
Lawn Maintenance
Lawn Mowers
Lawn Ornaments
Lawn Planting
Lawn Tools
Outdoor Growing
Overall Landscape Planning
Pests, Weeds & Problems
Plant Basics
Rock Garden
Rose Garden
Shrubs
Soil
Specialty Gardens
Trees
Vegetable Garden
Yard Maintenance
How to Kill Existing Crab Grass
How to Kill Existing Crab Grass. Crabgrass is an annual grassy weed. Crabgrass sprouts in established lawns in mid to late spring. These three to four blade sprouts quickly develop and spread. By the end of the summer, the mature plant's seed head turns purple as it prepares to deposit thousands of seeds in your lawn. One way to control existing...
Crabgrass is an annual grassy weed. Crabgrass sprouts in established lawns in mid to late spring. These three to four blade sprouts quickly develop and spread. By the end of the summer, the mature plant's seed head turns purple as it prepares to deposit thousands of seeds in your lawn. One way to control existing crab grass is to kill it before late summer when it sets seed. Herbicides will work on immature plants that sprout early in the season. However, the mature plants that have already produced their spindly growth are fairly resistant to chemicals and must be physically removed.
Things You'll Need
Herbicide
Trowel
Grass seed
Water your lawn the day before you dig or spray crabgrass plants. Watering will help the established lawn stand up to any residual pesticide spray. It will also make your lawn easier to dig.
Spray immature crab grass with a post-emergent herbicide scheduled for use on crabgrass. Immature crab grass is susceptible to herbicide at any point after germination until the plant produces more than five blades. Follow the herbicide's instructions and spray individual crabgrass plants until their foliage is well coated. Do not mow the lawn or water it for 24 hours after the application. Re-treat the crabgrass with the herbicide within seven to 14 days if necessary.
Dig mature crabgrass plants that have begun to produce numerous stems. Use a spade to dig out the plant and its roots. Discard all plant material.
Re-seed any bare patches left behind by digging or spraying. Seed warm-season grass in early spring and cool-season grass in early fall. Loosen the soil in the bare patch with a trowel. Then sprinkle a light covering of seed and pat it into the soil with your hands to ensure soil contact. Keep the soil moist with regular watering until roughly two weeks after the grass seed germinates.
Tips & Warnings
If the mature crabgrass is too numerous to dig, you may attempt to spray it with crabgrass herbicide. Repeat applications may only provide partial control, but the surviving adult plants can be uprooted.
Crabgrass reproduces by seed. The most effective way to keep crabgrass from coming back season after season is to apply a pre-emergent herbicide to the yard in early spring before the seed in your lawn germinates.
