Weed killer for lawns: how to choose the right one
The right weed killer for lawns is a selective herbicide that lists both your weed and your grass type on the label, applied at the right stage: a pre-emergent before seeds sprout, a post-emergent on weeds already growing. Name the weed first (broadleaf, grassy or sedge), check your grass type, then pick the active ingredient from the table below. Brand names change; active ingredients don't.
Contents
- Selective or non-selective: what kills weeds but not grass?
- Broadleaf, grassy or sedge?
- Pre-emergent or post-emergent?
- Liquid, granular or weed-and-feed?
- Check your grass type before you buy
- Which active ingredient for which weed?
- Natural and pet-friendly lawn weed killers
- How to apply lawn weed killer for the best results
- Common mistakes
- FAQ
Selective or non-selective: what kills weeds but not grass?
Selective herbicides kill certain plants and leave others. Lawn products are selective: a broadleaf herbicide kills dandelions but not turf, a crabgrass product kills crabgrass but not the lawn grass it is labeled for. Non-selective products such as glyphosate, glufosinate or vinegar-based sprays kill any green plant they touch, grass included. Use those only for clearing an area or for spot work in driveways and beds; our weed and grass killer guide covers them.
A homemade weed killer for lawns has the same problem: vinegar, salt and soap mixtures are non-selective, burn the grass around the weed, and salt stays in the soil. See homemade weed killer recipes and their limits before you try one on turf.
Broadleaf, grassy or sedge?
Lawn weeds fall into three groups, and each needs a different chemistry. A product for one group does little or nothing to the others.
- Broadleaf weeds have wide leaves with a network of veins and often showy flowers: dandelions, clover, creeping Charlie, wild violets, plantain, chickweed. They are the target of most lawn weed killers, covered in detail in our broadleaf weed killer guide.
- Grassy weeds are grasses you don't want: crabgrass, foxtail. Because they are grasses, broadleaf products don't touch them.
- Sedges look like grass but have triangular stems. Nutsedge needs a sedge-specific herbicide.
Pre-emergent or post-emergent?
A pre-emergent herbicide for lawns forms a barrier in the top layer of soil that stops seeds from developing. It does nothing to weeds already up, so timing is everything: for crabgrass, it goes down in early spring before soil temperatures reach the range where seeds sprout. Common lawn pre-emergents contain prodiamine, dithiopyr or pendimethalin. Our pre-emergent guide covers timing by region.
A post-emergent kills weeds that are already growing. It works best on young, actively growing weeds. Most lawn weed control combines both: a pre-emergent for annual grassy weeds in spring and a post-emergent for broadleaf perennials, ideally in fall.
Liquid, granular or weed-and-feed?
| Form | Best for | How to apply | Downside |
|---|---|---|---|
| Liquid concentrate or ready-to-use spray | Spot treating scattered weeds; faster results | Pump sprayer or trigger bottle, on dry leaves | Drift on windy days; mixing errors |
| Hose-end liquid | Broadcast over a weedy lawn | Walk at a steady pace to cover evenly | Harder to control the rate |
| Granular herbicide | Large areas; pre-emergents | Spreader. Broadleaf granules must stick to wet leaves: apply after dew or a light watering | Slower; wasted on dry foliage |
| Weed-and-feed (fertilizer + herbicide) | Lawns with weeds spread across the whole yard | Spreader, timed for both the weeds and the fertilizer | Treats weed-free areas too; the best time to feed is not always the best time to kill weeds |
Weed-and-feed is convenient, but it puts herbicide on every square foot, including tree and shrub root zones. Products containing dicamba can be taken up by tree roots under the lawn, so keep them away from the root zones of trees and shrubs. If weeds are scattered, spot-treating with a liquid uses far less product.
Check your grass type before you buy
Lawn grasses tolerate herbicides differently, and the label lists the grasses each product is safe on. Cool-season lawns of Kentucky bluegrass, tall fescue and perennial ryegrass (the North and transition zone) tolerate most common lawn herbicides. Warm-season lawns in the South need more care:
| Grass | Watch out for |
|---|---|
| Kentucky bluegrass, tall fescue, perennial ryegrass | Most broadleaf mixes, triclopyr and quinclorac are labeled; avoid treating new seedlings |
| Bermudagrass | Triclopyr can injure it; follow temperature limits, especially in summer |
| Zoysiagrass | Generally tolerates three-way broadleaf mixes; check label for other ingredients |
| St. Augustinegrass | Sensitive to many 2,4-D products and to triclopyr; use products labeled for St. Augustine |
| Centipedegrass | Sensitive to 2,4-D at higher rates, and to dicamba, MCPP and triclopyr; use products labeled for centipede |
Also avoid spraying warm-season lawns during spring green-up, when the turf is most easily injured.
Which active ingredient for which weed?
Use this as a starting point, then confirm on the label that it lists your weed and your grass.
| Weed | Type | Active ingredients to look for | Best timing |
|---|---|---|---|
| Dandelion, plantain | Broadleaf perennial | 2,4-D + MCPP + dicamba (three-way mix) | Fall; spring as a second window |
| Clover | Broadleaf perennial | Three-way mix, triclopyr (cool-season lawns) | Fall or spring, actively growing |
| Creeping Charlie, wild violets | Broadleaf perennial | Triclopyr or a mix containing it; repeat applications | Fall |
| Chickweed, henbit | Broadleaf, cool-season annual | Three-way mix with MCPP or dicamba | Fall or early spring while small |
| Spurge, oxalis | Broadleaf, summer weed | Pre-emergent in spring; post-emergent broadleaf mix on young plants | Late spring to summer |
| Crabgrass | Grassy annual | Pre: prodiamine, dithiopyr, pendimethalin. Post: quinclorac, fenoxaprop, mesotrione (cool-season) | Pre in early spring; post on young plants |
| Foxtail | Grassy annual | Pre: same as crabgrass. Post: fenoxaprop | Spring to early summer |
| Nutsedge | Sedge | Halosulfuron, sulfentrazone | Late spring to early summer, young plants |
| Moss | Non-vascular plant | Iron sulfate, potassium salts of fatty acids | Cool, moist weather; then fix the cause |
Natural and pet-friendly lawn weed killers
Iron HEDTA is a selective, iron-based weed killer that burns broadleaf weeds such as dandelion and clover without killing most grass. It acts only on the leaves it hits, so perennials regrow and need repeat treatments. Corn gluten meal is sold as a natural pre-emergent, but results in university trials have been inconsistent. Hand-pulling with a weeding tool is still the most reliable natural option for a few weeds.
"Pet friendly" on a label is not a guarantee. Whatever you use, keep pets and children off the treated lawn for as long as the label says and store products out of reach. Our pet-safe weed killer guide compares lower-risk choices.
How to apply lawn weed killer for the best results
- Check the temperatureMost broadleaf weeds are best treated when air temperatures are between 65 and 85°F. Above that, turf injury is more likely, and some ingredients volatilize and drift.
- Check the wind and rainSpray on a calm day, below about 5 mph, with coarse droplets at low pressure. Respect the rain-free period on the label; many say not to apply if rain is forecast within 24 hours.
- Don't mow right before or afterLeave a few days on each side so weeds have leaf surface to absorb the product and time to move it to the roots.
- Measure, don't guessMix and spread at the label rate. More product does not kill weeds faster; it injures the lawn.
- Wait before seedingMost pre-emergents and many post-emergents stop or injure new grass. The label gives the waiting period.
The label is the law: in the United States, using a herbicide in a way its label does not allow is illegal as well as risky. The label tells you the rate, the grasses it is safe on, temperature limits, the rain-free period and when people and pets can return.
Common mistakes
- Buying before identifying the weed: a broadleaf product will not touch crabgrass or nutsedge.
- Using a 2,4-D product on St. Augustine or centipede without checking the label.
- Spraying in summer heat, which burns turf and gives poor control of perennials.
- Applying pre-emergent to weeds already growing.
- Treating, then letting the lawn stay thin. Weeds return to bare spots; overseed and mow high.
Weed killer is one tool among several. Our lawn weeds guide covers mowing height, feeding and overseeding, which keep weeds from coming back once you have cleared them.
FAQ
What is the best weed killer for lawns?
The one that lists both your weed and your grass type on the label. For dandelions, clover and most broadleaf weeds, that is usually a three-way mix of 2,4-D, MCPP and dicamba; for crabgrass, a pre-emergent such as prodiamine or dithiopyr in spring or a post-emergent such as quinclorac; for nutsedge, halosulfuron or sulfentrazone. No single product controls every lawn weed.
Will lawn weed killer kill my grass?
A selective lawn herbicide used at the label rate on a grass type it lists should not kill the lawn, but it can injure turf if you apply it in heat above about 85°F, during spring green-up of warm-season grass, or on a sensitive grass. St. Augustinegrass and centipedegrass are sensitive to several common broadleaf ingredients, so always check the label.
Is weed and feed safe for pets?
No lawn herbicide is pet safe in a blanket sense. Labels tell you how long to keep people and pets off the treated area, usually until a spray has dried or granules have been watered in as directed. Follow that, store products out of reach, and see our pet-safe weed killer guide for lower-risk options.
What is a natural weed killer for lawns?
Iron HEDTA is a selective, iron-based product that burns many broadleaf weeds without killing grass, though perennials usually need repeat treatments. Corn gluten meal is sold as a natural pre-emergent, with inconsistent results. Vinegar and other homemade sprays are non-selective and kill grass too.
Can I use weed killer and seed at the same time?
Usually not. Most pre-emergents also stop grass seed, and most broadleaf herbicides should not be used until new grass has been mowed a few times. Mesotrione is one of the few ingredients labeled for use at seeding. Check the waiting period on the label before you seed.
When should I apply lawn weed killer?
Broadleaf killers work best in fall, with spring as a second window, when weeds are actively growing and temperatures are roughly 65 to 85°F. Crabgrass pre-emergent goes down in early spring before seeds sprout. See the weed control calendar for your region.
Related
- Broadleaf weed killerBroadleaf weed killer explained: how 2,4-D, MCPP, dicamba and triclopyr kill weeds but not grass, the best fall timing, and how to avoid drift and tree damage.
- Pre-emergentA pre-emergent herbicide stops weed seeds before they sprout. Which active ingredient to choose, when to apply it by region, and how to water it in.
- Pet-safe weed killerNo pet safe weed killer is risk-free. Learn the lower-risk options, how long to keep dogs and cats off treated areas, what to avoid and how to store products.
- Weed control calendarThe best time to spray weed killer by weed, season and region, plus the weather rules on the label. Pick your region for this month's lawn to-do list.
- Lawn weedsCommon lawn weeds by type (grassy, broadleaf, sedge), what each one says about your lawn, and the right control and timing to get rid of weeds in grass.
Updated October 3, 2026