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How to Kill Weeds in Your Lawn

By Eulalia Palomo
Well-timed weed control keeps weeds down all summer long.

A weed-free lawn rarely comes without effort. Weeds, which are basically any type of broad-leaf plant or grass you don't want growing in your lawn, will take over when not managed. The creep can be slow at first, almost unnoticeable, before you get a chance to take stock of the problem. Methods for killing weeds in your lawn range from the nontoxic, but labor-intensive hand weeding method to carefully targeted and applied herbicide applications.

Two types of weeds commonly invade lawns: grass-type weeds and broad-leaf perennial weeds.

Common Grass-Type Weeds

  • Crabgrass (Digitaria spp.), an annual grass that takes over lawns by slowly crowding out lawn grass. 
  • Goosegrass (Eleusine indica), an annual grass with flat stems that grows in clumps. Also called wiregrass.
  • Foxtail (Setaria spp.), an annual weedy grass with flat-leaf blades and large seed heads.

Common Broad-Leaf Weeds

  • Dandelions (Taraxacum officinale), the common yellow- flowering weeds seen all over unkept lawns. These perennials, which grow in U.S. Department of Agriculture zones 3 through 9, have deep taproots. 
  • Broadleaf plantain (Plantago major), a low-growing broad-leaf weed hardy in USDA zones 3 through 10. 

Hand Weeding

Hand weeding is an effective, nontoxic way to kill weeds in the lawn. Use a dandelion knife -- a narrow weeding tool designed to dig out dandelion taproots -- to dislodge perennial weed roots. If you leave root parts in the soil, some weeds will just regrow from the root. A dandelion knife is also effective for sliding under weedy grasses. Early in the season, or as soon as the weeds appear, is the best time to weed by and. Make sure to get dandelions and other flowering weeds before they go to seed or your task will be doubly hard next near.

Using Herbicides

Look for a herbicide that contains 2, 4-D along with dicamba to target a range of broad-leaf lawn weeds. For weedy grasses, look for a product that also contains quinclorac. You can find herbicides that contain a combination of these ingredients to control both broad-leaf weeds and weedy grasses at the same time. These ingredients should be listed on the front of the label, typically in the lower left-hand corner. Use herbicides to spot-spray the affected area rather than spraying the whole lawn area. Spray in the spring and early summer when weeds are actively growing. Wait for a dry day with temperatures between 45 and 90 degrees Fahrenheit.

How to Apply

Put on long sleeves, shoes and socks, safety goggles and rubber gloves before starting.

Mix 1 to 2 ounces of concentrated herbicide with 1 gallon of water in a 1-gallon sprayer. This is enough to cover a 500-square-foot area.

Spot-spray weeds in the lawn until the leaves are damp but not dripping. Avoid using so much that the herbicide pools or puddles around the weed.

Spray again 14 days after first application. This helps target and eliminate weeds like dandelions, crabgrass and foxtail. Do not use more than twice a year.

Wait to mow the lawn for at least two days after spraying weeds, and make sure the clippings go in the garbage, not in the compost or mulch pile.

Wait four weeks before reseeding the area after spraying herbicides.

 

Things You Will Need

  • Granular weed killer herbicide (based on weed type)
  • Garden shovel

About the Author

 

Eulalia Palomo has been a professional writer since 2009. Prior to taking up writing full time she has worked as a landscape artist and organic gardener. Palomo holds a Bachelor of Arts in liberal studies from Boston University. She travels widely and has spent over six years living abroad.