Weed and grass killer: choosing and using a non-selective spray
A weed and grass killer is a non-selective herbicide: it kills or damages every green plant it touches, lawn grass included. Use it where nothing should grow — driveway cracks, patios, fence lines — or to clear ground for a new bed or lawn, and pick the active ingredient by whether you need the roots dead, fast results, or months of bare ground.
Contents
- Which weed and grass killer ingredient do you need?
- Is glyphosate legal, and is it safe?
- Products that keep the ground bare: read this first
- Where should you use a weed and grass killer?
- How to apply a weed and grass killer without drift
- Homemade and natural weed and grass killers
- How to kill grass without spraying
- FAQ
The name causes a lot of dead lawns. “Weed and grass killer” means it kills weeds and grass. Products that kill weeds but not grass are selective lawn herbicides, a different category covered in our lawn weed killer guide. For how both families fit together, see the overview of weed killer types.
Which weed and grass killer ingredient do you need?
Turn the bottle around and read the active ingredients. Almost every product on the shelf is built from one or more of these.
| Active ingredient | How it works | Kills roots? | Speed | Best for |
|---|---|---|---|---|
| Glyphosate | Systemic: moves from leaves to roots, rhizomes and runners | Yes | Slow, about a week to show | Perennial weeds and grasses, lawn renovation |
| Glufosinate | Locally systemic: moves within treated leaves only | Rarely on perennials | A few days | Annual weeds and grasses, edging near plants |
| Diquat | Contact | No | Within a day | Small annual weeds, quick cleanups |
| Pelargonic acid, ammonium nonanoate, acetic acid | Contact: destroys leaf surfaces | No | Hours | Seedlings in cracks and gravel |
| Imazapyr and other soil-residual ingredients | Absorbed by leaves and roots; stays active in soil | Yes | Slow, then lasts months | Bare ground where no roots of wanted plants reach |
Speeds are typical; cool weather slows most products, and each label states its own timing.
Glyphosate: kills roots, leaves the soil alone
Glyphosate is absorbed through green leaves and carried down to the roots, which is why it can kill perennials such as bindweed and Bermudagrass that contact sprays only scorch. It is slow — expect yellowing after about a week and full results later on tough perennials, which may need a second application. Once it reaches the soil it is bound tightly to soil particles, so it has little or no residual activity: it won’t stop new seeds from sprouting, and you can usually replant once the label’s waiting period has passed.
Glufosinate: faster, but less on perennials
Glufosinate moves within the leaves it lands on but not through the whole plant, so damage stays close to where it was sprayed. That makes it a little more forgiving when edging beside plants, and it acts faster than glyphosate, but perennials with rhizomes or runners usually regrow.
Contact acids and diquat: quick burndown only
Pelargonic acid, ammonium nonanoate and acetic acid destroy the waxy surface of leaves, and diquat kills tissue on contact. Results can show within hours, which makes them popular for weeds in the driveway and gravel. Roots survive, so perennials return, and you’ll be re-spraying through the season. Natural versions are compared in our natural weed killer guide.
Is glyphosate legal, and is it safe?
Glyphosate is legal in the United States. It is registered by the EPA, and homeowners can buy and use glyphosate products as long as they follow the label. The debate around it is real, though, so here is where things stand.
- Federal status: the EPA has concluded that glyphosate is not likely to be carcinogenic to humans when used according to the label. In 2022 a federal appeals court sent part of the agency’s 2020 review back for more analysis, and the EPA withdrew that interim decision. Glyphosate stays registered while the agency completes its updated review.
- The other view: in 2015 the International Agency for Research on Cancer (IARC), part of the World Health Organization, classified glyphosate as “probably carcinogenic to humans.” The two bodies answer different questions: IARC rates whether a substance can cause cancer under some circumstances, while the EPA weighs the risk at the exposures people actually get.
- California: glyphosate is on the state’s Proposition 65 list, but federal courts have blocked California from requiring a cancer warning on glyphosate products.
- Local rules: some cities, counties and school districts limit or stop its use on parks, playgrounds and other public land. A few places also restrict cosmetic lawn pesticides on private property, so check your county’s rules if you are unsure.
- On store shelves: after years of lawsuits claiming its weed killers caused cancer, the best-known consumer brand reformulated its home lawn and garden line without glyphosate in 2023, citing litigation risk rather than safety. Glyphosate products from other makers are still sold to homeowners. In June 2026 the US Supreme Court ruled that state-law claims demanding a cancer warning cannot override a label the EPA has approved.
In practice, the label is your safety standard: wear the gloves and eye protection it calls for, spray on a calm day, and keep children and pets off the area until it has dried or for as long as the label says. If you would rather not use glyphosate, glufosinate and contact sprays handle annual weeds, and pulling, smothering and the methods in our natural weed killer guide work without any synthetic herbicide.
Products that keep the ground bare: read this first
Some weed and grass killers promise to stop regrowth for months or up to a year. They do it by adding a soil-residual herbicide — imazapyr is a common one — to a fast-acting ingredient. Residual products can be useful on gravel lots and fence lines far from any plant, but they carry risks most buyers don’t expect:
- They kill trees and shrubs through the roots. Tree roots spread far beyond the canopy and under driveways and walks. A tree can absorb the herbicide from soil you sprayed several yards away.
- They move with water. Imazapyr can move in soil and with runoff, down a slope and into lawns, beds or a neighbor’s yard.
- Nothing grows for a long time. Treated soil can stay bare for a year or more, so never use these products where you may plant later.
Check the label for root-zone limits: residual products typically forbid use over the roots of trees and shrubs, often defined as an area well beyond the drip line. If you can’t be sure no roots are there — near any tree, hedge or lawn — choose glyphosate or a contact spray instead.
Where should you use a weed and grass killer?
Driveways, patios and sidewalks
Cracks and joints are the classic job. Spray young weeds with a contact product or treat persistent perennials with glyphosate, then fill the joints with sand or polymeric sand so seeds have less room to lodge. Keep spray off the lawn edge: a strip of dead grass along the drive is the usual sign of overspray. Our pages on driveway weeds and weeds in gravel cover non-spray options too.
Renovating a lawn or starting a new bed
To replace a weedy lawn, spray the whole area with glyphosate while the grass and weeds are actively growing, then follow the label before mowing, tilling or seeding — many labels advise waiting several days so the herbicide reaches the roots. Perennial grasses such as Bermudagrass often need a second application after regrowth. Once the old turf is dead, you can seed or sod as soon as the label allows.
Fence lines and along buildings
A careful glyphosate spot treatment works well. Avoid residual products where fences or foundations run near trees, shrubs or lawns.
How to apply a weed and grass killer without drift
- Read the labelCheck the site is allowed (lawn renovation, driveway, around trees), the mixing rate, the rainfast time and the replanting interval. The label is the law.
- Pick a calm, dry dayWind carries fine droplets onto shrubs, gardens and lawns. Make sure no rain is expected before the product is rainfast.
- Use low pressure and a coarse sprayBig droplets drift less. Hold the nozzle close to the weed and use a piece of cardboard as a shield near plants you want to keep.
- Wet the leaves, don’t drenchSpray to cover the foliage evenly; runoff onto soil is wasted product and drift risk.
- Protect yourself and othersWear gloves, long sleeves and eye protection, and keep people and pets off until the spray has dried or as the label says.
Never spray a non-selective product onto green bark of young trees, suckers or exposed roots, and never mix two herbicides or household chemicals yourself.
Homemade and natural weed and grass killers
A homemade weed and grass killer made with vinegar and a little dish soap works like a weak contact spray: it browns young weeds and grass on a sunny, warm day but leaves roots alive. It is a reasonable choice for seedlings in pavement cracks. The recipe, its limits and what not to add are in our homemade weed killer guide.
Skip salt. It will kill weeds and grass, but it does so by poisoning the soil, and it spreads with every rain into the lawn and beds next to where you used it. Skip bleach too, and never mix it with vinegar: together they release toxic chlorine gas.
How to kill grass without spraying
- Smother it: mow short, cover with overlapping cardboard, wet it and top with several inches of mulch. Most turf dies within a season; strong perennial grasses may push through edges.
- Solarize it: in hot summer regions, clear plastic over moist soil for 4 to 6 weeks in midsummer kills turf and many weed seeds.
- Dig it out: a flat spade or a rented sod cutter removes turf for a bed immediately. Watch for runners of Bermudagrass and other spreading grasses, which regrow from pieces left behind.
To keep lawn grass from creeping into flower beds afterward, install a solid edging and treat invaders early with a selective grass herbicide labeled for use around your ornamentals.
FAQ
What is the best weed and grass killer?
It depends on the job. For perennial weeds and grass you want gone roots and all, a glyphosate product is the usual choice because it moves to the roots. For quick results on young weeds in cracks, a contact spray (pelargonic acid, ammonium nonanoate, acetic acid or diquat) acts within hours. Products that add a soil-residual ingredient last longer but can kill nearby trees, so use them only where the label allows and no roots reach.
Is glyphosate banned in the US?
No. Glyphosate is registered by the EPA and legal to buy and use in every state when you follow the label. Some cities, counties and school districts restrict it on public land, and a few places limit cosmetic lawn pesticides on private property, so check local rules.
Will weed and grass killer kill my lawn?
Yes. Weed and grass killers are non-selective, so they kill lawn grass as readily as weeds. To kill weeds without harming turf, use a selective lawn product labeled for your grass type; see our lawn weed killer guide.
How long after weed and grass killer can I plant?
Check the label: it gives the replanting interval. Glyphosate-only products generally have little or no soil activity, so their labels often allow planting soon after the weeds have died back. Products with residual ingredients such as imazapyr can prevent anything from growing for months to a year or more.
Will salt kill weeds and grass?
Yes, but it does so by poisoning the soil. Salt stays where it lands, washes into nearby lawns and beds with rain, and can leave ground bare for a long time. It is not a good substitute for a weed and grass killer.
Is there a grass killer for flower beds that won’t hurt flowers?
Yes: selective grass herbicides containing sethoxydim, fluazifop or clethodim kill many grasses growing among broadleaf ornamentals. They do not control broadleaf weeds or nutsedge, and each label lists the ornamentals it can be sprayed over, so check that your plants are on it.
Is there a weed and grass killer safe for pets?
No weed killer is safe in every situation. Keep pets off treated areas until the spray has dried or for as long as the label says, whichever is longer, and store products out of reach. Our pet-safe weed killer guide lists lower-risk options.
Related
- Weed killersWhich weed killer do you need? Selective or non-selective, systemic or contact, pre- or post-emergent, organic or homemade, matched to lawn, beds and driveway.
- Driveway cracksWeeds in driveway cracks: pull or scrape them, kill them with boiling water, flame or a labeled spray, then seal cracks or refill paver joints so they stay out.
- Natural weed killerThe natural weed killer options that work: pulling, smothering, boiling water, vinegar, fatty acid sprays, plant oils, solarization and flame, and their limits.
- 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.
Updated October 3, 2026