How to Get Rid of Lawn Weeds (and Keep Them Out)

Weeds are opportunists. They show up wherever your lawn is thin, hungry, or stressed, and once they take hold they spread fast. The good news is that getting rid of lawn weeds, and keeping them out for good, comes down to a simple two-part strategy: kill what is already there, then grow turf so thick that new weeds never get a foothold. This guide walks you through identifying the most common culprits, choosing the right herbicide at the right time, and building a season-by-season plan that keeps your grass winning.

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Identify the weed before you treat it

The single most common weed-control mistake is spraying before you know what you are dealing with. Different weeds respond to different products and timing, and a few impostors (like nutsedge) shrug off standard lawn weed killers entirely. Spend two minutes identifying the plant and you will save yourself money, wasted effort, and damaged turf.

The usual suspects

• Crabgrass — a low, sprawling annual grass that germinates in spring and dies at frost, dropping thousands of seeds. Light green, coarse, and star-shaped from above.
• Dandelion — the classic yellow flower with a deep taproot and puffball seed head. A broadleaf perennial that returns from the root if you do not get all of it.
• Clover — small three-leaf clusters with white flowers. It actually fixes nitrogen, so heavy clover often signals an underfed lawn.
• Nutsedge (nutgrass) — bright, glossy, V-shaped grass-like blades that grow faster than your turf and stand taller a few days after mowing. It is a sedge, not a grass or broadleaf, and needs a special herbicide.
• Creeping Charlie (ground ivy) — a creeping broadleaf with scalloped, round leaves and a minty smell when crushed. Loves shade and damp soil, and roots wherever it touches down.
• Spurge — a flat, mat-forming summer annual with small oval leaves and a milky sap. Thrives in hot, compacted, thin areas like driveway edges.

A thick, healthy lawn is your best defense

Herbicides treat the symptom. A dense, vigorous lawn treats the cause. When grass grows thick enough to shade the soil surface, weed seeds never get the light they need to germinate, and the few that sprout get outcompeted for water and nutrients. Most chronic weed problems are really turf-health problems in disguise.

Build turf that crowds weeds out

• Mow high. Keep cool-season grass around 3 to 3.5 inches and never remove more than a third of the blade at once. Taller grass shades the soil and starves weed seeds of light. See our guide on how often to mow your lawn.
• Feed it on schedule. A hungry lawn thins out and invites clover and crabgrass. Follow a lawn fertilizer schedule matched to your grass type.
• Water deeply and infrequently. One inch per week in a couple of soakings builds deep roots; daily sprinkles favor shallow-rooted weeds.
• Overseed thin spots in fall. Bare soil is an open invitation. Filling gaps with grass is the cheapest weed control there is.
• Aerate compacted soil. Spurge, nutsedge, and many weeds thrive in compaction. Core aeration relieves it and helps grass roots spread.

Pre-emergent vs. post-emergent herbicides

Understanding these two categories is the key to the whole game. They do completely different jobs, and using the right one at the right moment matters far more than which brand you buy.

Pre-emergents stop seeds before they sprout

A pre-emergent creates a chemical barrier in the top layer of soil that stops weed seeds from establishing as they germinate. It does nothing to weeds you can already see. For crabgrass and other summer annuals, apply in early spring when soil temperatures reach about 55°F at a depth of a couple inches, which is roughly when forsythia blooms and well before you see any crabgrass. A second application in early fall targets winter annuals. A reliable pre-emergent crabgrass preventer is the cornerstone of any prevention plan. One catch: do not apply pre-emergent if you plan to seed, because it blocks your grass seed from germinating too.

Post-emergents kill weeds you can see

Post-emergents target actively growing weeds. They work best on young, unstressed plants, so treat early in the weed’s life and avoid spraying during drought or extreme heat. Most broadleaf weeds in a lawn are handled by a selective lawn weed killer that kills the weed while leaving your grass unharmed.

Selective vs. non-selective, spot vs. whole-lawn

Selective vs. non-selective

• Selective herbicides kill specific plant types and spare your turf. A broadleaf selective wipes out dandelion, clover, and creeping Charlie without harming the grass. These are what you want for almost all in-lawn weeding.
• Non-selective herbicides (like glyphosate) kill anything green, grass included. Reserve them for driveway cracks, patio edges, mulch beds, or killing off a patch before a full reseed. Never broadcast them across a lawn.

Spot-treating vs. whole-lawn application

If weeds are scattered, spot-treat them with a handheld sprayer. You use less product, save money, and reduce chemical load on the lawn. Switch to a whole-lawn broadcast application only when more than roughly a third to half of the lawn is infested. For pre-emergents, always treat the entire lawn, since the goal is a continuous barrier with no gaps for seeds to slip through.

Natural, organic, and hand-pulling options

You do not have to reach for synthetic chemicals to win the weed war, especially if you stay on top of it. For more detail on products, see our roundup of the best weed killers.

Lower-chemical and manual methods

• Hand-pulling and digging. The original organic method, and unbeatable for taprooted weeds like dandelion. Pull after rain when soil is soft, and get the entire root or it grows back. A long-handled weed puller tool lets you remove taproots without kneeling.
• Corn gluten meal. A natural pre-emergent that suppresses germinating seeds and adds nitrogen. It is slower and less reliable than synthetics but fits an organic program.
• Horticultural vinegar (20% acetic acid). A non-selective contact burner for cracks and edges. It kills the tops on contact but often not perennial roots, so expect regrowth.
• Boiling water. Effective and free for weeds in driveway and walkway cracks.
• Smother and mulch. In beds, a thick mulch layer or cardboard sheeting starves weeds of light.

One important note: natural contact treatments are non-selective, so they will scorch your grass too. Use them on hardscape and bare areas, not in the middle of your turf.

Your season-by-season weed plan

Weed control is a calendar, not a single event. Here is a year-round rhythm that keeps you ahead of the problem instead of always reacting to it.

• Early spring. Apply your pre-emergent crabgrass preventer when soil hits about 55°F. Do this before weeds appear, and skip it if you are spring-seeding.
• Late spring. Spot-treat any broadleaf weeds with a selective killer while they are young. Begin mowing high to start shading the soil.
• Summer. Hand-pull stragglers and spot-treat nutsedge with a sedge-specific product. Avoid spraying in peak heat or drought, which stresses both weeds and grass. Water deeply to keep turf dense.
• Early fall. The best time for broadleaf control. Perennials like dandelion and creeping Charlie are pulling energy into their roots, so a selective herbicide gets carried down and kills them for good. Apply a fall pre-emergent for winter annuals if you are not seeding.
• Fall. Overseed thin and bare spots and fertilize to send the lawn into winter thick and strong. This is your highest-leverage move for next year’s weed pressure.
• Late fall/winter. Plan ahead, sharpen the mower blade, and rest. A clean mowing cutoff and a healthy lawn going dormant means fewer weeds come spring.

Lawn care is just one piece of a great yard. For the bigger picture on creating a space you love, explore our outdoor living guide.

Frequently asked questions