Best Weed Killer for Lawns

For most established lawns, Spectracide Weed Stop for Lawns Plus Crabgrass Killer and Ortho WeedClear are the best weed killers for lawns because they remove broadleaf weeds and, in the Spectracide case, crabgrass, without killing common turfgrass when used as directed. Syngenta Tenacity is the pick for new seedings and cool-season specialty turf, Roundup for Lawns suits northern grasses with mostly broadleaf problems, and Scotts Turf Builder Weed & Feed is the choice when you also want to fertilize in the same pass.

The wrong weed killer does more damage than weeds do. A product that kills clover and dandelions may scorch St. Augustine, a crabgrass killer may be useless on nutsedge, and a non-selective spray used on a lawn will leave brown patches. So this guide starts with the question that decides everything: what weed do you have, what grass do you own, and what time of year is it. Then it matches products to that situation, shows a worked coverage calculation, and covers the safety steps that most labels bury in fine print.

Quick picks

• Best all-round selective killer: Spectracide Weed Stop for Lawns Plus Crabgrass Killer (quinclorac plus broadleaf herbicides).
• Best for warm- and cool-season turf variety: Ortho WeedClear Lawn Weed Killer, labeled for Bermudagrass, fescue, Kentucky bluegrass, ryegrass and zoysiagrass.
• Best for northern lawns with broadleaf weeds: Roundup for Lawns, labeled for Kentucky bluegrass, tall fescue and perennial ryegrass.
• Best for new seedings and tough grassy weeds: Syngenta Tenacity.
• Best weed-and-feed combination: Scotts Turf Builder Weed & Feed.
• Best for crabgrass with broadleaf control: Ortho Weed B Gon Plus Crabgrass Control.
• Best for southern lawns: PBI-Gordon Speedzone Southern Broadleaf Herbicide.
• Best for nutsedge: Sedgehammer.
• Best preventive step for crabgrass: Scotts Halts Crabgrass Preventer.

How we chose

This is a research-based guide, not a physical test. We compared product labels and manufacturer pages, extension-service weed control guidance, and widely cited buyer guides to find which products consistently appear for lawn use and what each is labeled to control. We then grouped products by what buyers need to decide: weed type, turfgrass compatibility, application format (ready-to-spray versus concentrate versus granular), rainfast time, seeding restrictions and coverage. Because labels change and coverage figures vary by package, we describe formats and spec classes and tell you where to read the exact container figure. Always follow the label on the product in your hand; the label is the law for herbicides.

Step one: identify the weed and the grass

Weeds fall into three groups, and no single product handles all of them equally.

• Broadleaf weeds: dandelion, clover, plantain, chickweed, henbit, ground ivy. Most selective lawn weed killers with 2,4-D, dicamba, MCPP or similar actives control these.
• Grassy weeds: crabgrass, foxtail, goosegrass. These need a grass-active ingredient such as quinclorac (in Spectracide’s crabgrass formulation) or a specialty product such as Tenacity, or a pre-emergent applied in spring before seeds sprout.
• Sedges: nutsedge has triangular stems and needs a sedge-specific active such as halosulfuron (the active in Sedgehammer). Standard broadleaf killers usually do not stop it.

Your turf matters just as much. Cool-season grasses (Kentucky bluegrass, tall fescue, perennial ryegrass) and warm-season grasses (Bermudagrass, zoysia, centipede, St. Augustine) tolerate different chemistries. Centipede and St. Augustine are the most sensitive and often have label restrictions, so read the turf list on the container before buying.

Comparison table

The products in detail

Spectracide Weed Stop for Lawns Plus Crabgrass Killer

Spec line: Concentrate and ready-to-spray formats · quinclorac with broadleaf actives (2,4-D and dicamba) · targets dandelion, clover, chickweed, crabgrass and foxtail · selective on common turfgrass.

Best for: Lawns with a mix of broadleaf weeds and crabgrass in cool-season or Bermuda and zoysia turf.

Skip if: You have St. Augustine or centipede grass and have not confirmed the label, or you are seeding within the label waiting period.

Pros: Controls both broadleaf and grassy weeds in one product; concentrates stretch over a large area.

Cons: Heavy crabgrass may need a second pass about two weeks later; mixing requires a pump sprayer.

Ortho WeedClear Lawn Weed Killer

Spec line: Ready-to-spray wand and hose-end or concentrate options · selective broadleaf control · rainproof in about 1 hour · labeled for Bermudagrass, fescue, Kentucky bluegrass, ryegrass and zoysiagrass.

Best for: Homeowners with several turf types or who need a fast rainproof window.

Skip if: Crabgrass is your main problem, since this is a broadleaf-focused product.

Pros: Wide list of safe turf types, quick rainfast time, easy wand format for spot jobs.

Cons: Not a crabgrass or sedge killer; ready-to-spray wands cost more per square foot than concentrates.

Roundup for Lawns

Spec line: Ready-to-use · selective broadleaf control · designed for northern grasses (Kentucky bluegrass, tall fescue, perennial ryegrass) · rainproof in about 3 hours · up to about 3 months of control claimed.

Best for: Northern lawns with dandelion and clover problems.

Skip if: You have a southern lawn, since this formula is aimed at northern turf, or if you confuse it with non-selective Roundup that kills grass.

Pros: Familiar brand, easy to use, long control window.

Cons: Not for every grass type; do not substitute a non-selective Roundup product on turf.

Syngenta Tenacity

Spec line: Liquid concentrate · mesotrione · pre- and post-emergent activity on many weeds · can be used at seeding on labeled cool-season turf.

Best for: New lawns, overseeded areas and tough grassy weeds in cool-season turf.

Skip if: You need an inexpensive broad broadleaf spray for a large lawn.

Pros: Flexible timing around seeding, effective on hard-to-control grassy weeds.

Cons: Can cause temporary whitening of treated weeds and sometimes grass; the product is a specialty item, so follow rates carefully.

Scotts Turf Builder Weed & Feed

Spec line: Granular · fertilizer plus broadleaf herbicide · applied with a spreader to damp foliage per label.

Best for: Spring feeding when broadleaf weeds are also present.

Skip if: You are seeding, or if the lawn is drought-stressed or hot, because granular herbicides can burn turf.

Pros: One pass handles weeds and feeding; spreader settings are printed on the bag.

Cons: Less targeted than a spray; uneven spreading leaves streaks; do not apply near trees and shrubs without checking the label.

Ortho Weed B Gon Plus Crabgrass Control

Spec line: Concentrate or ready-to-spray · broadleaf plus crabgrass control · intended for common lawn grasses.

Best for: Lawns with crabgrass and broadleaf weeds together.

Skip if: You have sensitive turf such as centipede or St. Augustine without verifying the label.

Pros: Familiar format, treats two weed classes at once.

Cons: Mature crabgrass is harder to kill; a pre-emergent works better when planned early.

PBI-Gordon Speedzone Southern Broadleaf Herbicide

Spec line: Liquid concentrate · multi-active broadleaf formula · designed for warm-season turf.

Best for: Bermudagrass, zoysia and similar southern lawns with stubborn broadleaf weeds.

Skip if: You have a cool-season lawn, since the Southern formulation targets warm-season turf.

Pros: Strong on tough weeds and works in cooler weather.

Cons: Often sold through specialty channels; requires accurate mixing and a sprayer.

Sedgehammer

Spec line: Halosulfuron active · selective nutsedge control · used with surfactant per label.

Best for: Lawns overrun by nutsedge that did not respond to standard broadleaf sprays.

Skip if: Your problem is dandelion, clover or crabgrass.

Pros: One of the few lawn-safe sedge options.

Cons: Narrow target and may need repeat applications.

Scotts Halts Crabgrass Preventer

Spec line: Granular pre-emergent · stops crabgrass seeds from sprouting · applied in early spring.

Best for: Preventing crabgrass before it starts.

Skip if: You are seeding in the same season, because most pre-emergents block grass seed too.

Pros: Prevents rather than treats and reduces later spraying.

Cons: Timing is critical, and it does not kill weeds already growing.

Decision matrix: which weed killer for which problem

Worked example: coverage and sprayer math for a 6,000 square foot lawn

Labels list coverage by container and package type, and the figures differ widely between sources, so treat the printed label as the authority and do the math yourself.

1. Measure the treatable area. Suppose the front and back lawns are 40 by 100 feet (4,000 square feet) plus 2,000 square feet of side and rear turf: 6,000 square feet total. Subtract house, beds and paved areas so you only count grass.
2. Find the label coverage. Concentrates list a coverage figure per bottle; Spectracide concentrate sources, for example, quote numbers from several thousand up to tens of thousands of square feet depending on bottle size, so confirm yours.
3. Divide. If your bottle covers 16,000 square feet, 6,000 divided by 16,000 is 0.375 bottle, so one bottle covers the job with roughly 60 percent left for a second pass.
4. Calibrate the sprayer. Spray plain water over a 100 square foot test strip and measure how much a pump sprayer uses. If it takes 0.25 gallon per 100 square feet, 6,000 square feet needs about 15 gallons of mix. Mix the label rate of concentrate for that volume.
5. Plan the second pass. Dense crabgrass may need a repeat treatment about 14 days later, so reserve the remaining product and check the label for maximum applications per season.

The takeaway: for lawns over a few thousand square feet, a concentrate with a pump sprayer is far cheaper per square foot than a ready-to-spray wand, while ready-to-spray wins for small yards and spot jobs where mixing is more trouble than it is worth.

Timing: when to apply

Apply post-emergent killers when weeds are actively growing, usually in spring and early fall, and when temperatures fall inside the label range. Many labels advise against spraying when air temperatures are high, often around the mid-80s Fahrenheit or higher, because turf can be injured. Avoid spraying drought-stressed grass, and give the lawn a normal watering a day or two before so it is not under stress. Do not mow immediately before or after spraying, as the weed needs leaf surface to absorb the herbicide and time to move it through the plant. Check the rainfast period on the label: Ortho WeedClear lists about an hour and Roundup for Lawns about three hours, but other products differ.

Pre-emergents need different timing. Apply a crabgrass preventer in early spring before soil temperatures encourage germination, and water it in per label. If you plan to seed, choose Tenacity or wait until after the label’s seeding interval; most pre-emergents and many broadleaf killers delay grass seed germination.

Safety and application guidance

• Read the whole label before buying and again before mixing; it states the legal rates, turf list and re-entry guidance.
• Wear long sleeves, long pants, chemical-resistant gloves and eye protection. Wash exposed skin and launder clothing separately after application.
• Keep children, pets and bystanders off the lawn until the spray has dried or for the time the label specifies.
• Do not spray on windy days; drift can damage vegetable gardens, flowers, trees and shrubs. Keep spray off ornamentals and well away from tree and shrub roots unless the label allows.
• Never apply near storm drains, wells, ponds or streams, and do not apply before heavy rain unless the label permits.
• Do not use grass clippings from recently treated lawns as mulch in vegetable beds until the label says it is safe.
• Store products in their original containers, out of reach of children and pets, and dispose of leftovers through your local hazardous-waste program.
• Do not mix products or exceed the label rate; more is not better and can injure turf.

When a weed killer is not the answer

Lawns full of weeds are often lawns with bare soil, compaction or low mowing height. A thick lawn shades weed seed and wins the competition without chemicals. Mow tall (often three inches or more for cool-season grass), water deeply and less often, overseed thin spots in fall, and fertilize on a schedule that suits your grass type. A soil test tells you whether pH or nutrient shortages are weakening the turf. Pull isolated weeds by hand after rain, when roots release easily, and spot treat only what comes back.

Frequently asked questions

What is the best weed killer for lawns?

Spectracide Weed Stop for Lawns Plus Crabgrass Killer and Ortho WeedClear are the most often recommended selective lawn weed killers.

Choose Spectracide for a mix of broadleaf weeds and crabgrass, Ortho WeedClear for broad turf compatibility, and Tenacity for new seedings.

Will weed killer kill my grass?

Selective lawn weed killers are designed to leave labeled turfgrasses alive, but misuse can injure grass.

Check that your grass type is on the label, avoid hot and dry weather, never exceed the rate, and never use non-selective sprays on the lawn.

How long does lawn weed killer take to work?

Most selective broadleaf killers show twisting or curling within a few days and full results in one to three weeks.

Crabgrass may take longer, and dense infestations may need a second application about two weeks later, within the label’s seasonal limit.

When is the best time to apply weed killer to a lawn?

Apply post-emergent products in spring or fall while weeds are actively growing and temperatures are mild.

Apply crabgrass preventers in early spring before germination. Avoid spraying in high heat or drought.

Can I seed after using weed killer?

It depends on the product: many broadleaf killers require a waiting period before seeding, often several weeks, while Tenacity is labeled for use at seeding.

Check the label’s reseeding interval. Pre-emergent crabgrass preventers also block grass seed, so avoid them in seeding seasons.

Is weed and feed worth using?

Weed and feed saves a pass when you need both fertilizer and broadleaf control, but it is less targeted than a spray.

Apply it to a healthy, damp lawn in mild weather, set the spreader per the bag, and avoid heat or drought, which raise the burn risk.

How soon can pets and kids go back on the lawn?

Follow the label, but the general rule is to keep them off until the spray has fully dried or the time listed has passed.

Granular products often need watering in and then a drying period, so confirm the instructions on the specific product.

What kills nutsedge in a lawn?

Nutsedge needs a sedge-specific herbicide such as Sedgehammer, since standard broadleaf killers rarely control it.

Apply to actively growing sedge, repeat if the label allows, and improve drainage, since nutsedge thrives in wet, compacted soil.

The bottom line

Diagnose first: broadleaf weeds call for Ortho WeedClear or Roundup for Lawns on the right turf, crabgrass calls for Spectracide Plus Crabgrass Killer or a spring preventer, nutsedge calls for Sedgehammer, and new seedings call for Tenacity. Check the turf list, spray in mild weather, follow the rate and safety rules on the label, and build a thicker lawn so weeds have less room to return.