Best Weed Killers for Lawn that Won’t Kill Grass

Updated on by Jared Belson | Please note that there may be affiliate links on this page.

Weeds and wild grass are two of the most common problems homeowners have. Weeds find a way to emerge in the most inconvenient of times, and they always start very small and scattered, which makes them difficult to see. Only using the best weed killers for lawn maintenance may help you reshape your lawn into something your neighbors will envy.

Although most common herbicides are relatively easy to use, some of them may require some certain application tricks. Hopefully, this article will answer all your questions regarding where, how, and when to use weed killers for optimum results.

8 Best Weed Killers for Lawn Maintenance

If you’re looking to make short work of weeds, the Speed Zone Lawn Weed Killer is one of your best options. It comes in a 20oz spray bottle and requires no mixing on your part. It’s an easy-to-use weed killer that can work on most lawn grasses.

To get the maximum result with the Speed Zone, you should use this formula during colder weather. That’s because it doesn’t take much heat or sunlight to dry it. When used in cooler conditions, the weeds will have more time to absorb the herbicide.

In terms of coverage, the 20oz of formula can help you treat up to 18,000sq.ft. Although, realistically, you’re looking more at 14,000sq.ft. That’s still great if you own a large property.

The weed killer isn’t called Speed Zone without reason. The formula is very fast-acting. It kills most weeds in a couple of hours and continues working for up to two weeks. After two weeks you can reseed.

Given that this weed killer works equally well on most turfs and against most common weed species, it’s a great all-around weed killer in my book. Maybe not the cheapest or readily available across the country, but still good at the job.

  • Very fast weed killer
  • Remains active for up to two weeks
  • Great coverage per ounce
  • Suitable for both spot and broadcasting treatments
  • Not available in DC, MA, AK, NK, VT

The Monterey LG5518 is a herbicide concentrate, formulated to kill broadleaf weeds. It works as a post-emergent herbicide, so it has pretty decent weather resistance and a fast absorption rate.

The formula does a great job when it comes to controlling bermuda grass, kikuyugrass, and other perennial grasses. So you see, while this may not be a well-rounded herbicide, it’s still one of the best in its niche.

You can use it on cool-season grass without worries, as long as you follow the instructions. Yes, because it’s a concentrate, you’ll have to mix it on your own. That said, one pint of properly mixed Monterey LG5518 broadleaf herbicide should be enough to treat over 20,000sq.ft.

I like that the formula is 61.6% made of active ingredients. That ensures its potency, even though it may take weeks before you can reseed. Although it may not be the safest herbicide to use around sensitive grasses, it’s not as harmful as you may think to trees and ornamental plants.

You can get this selective formula in various quantities, too. Depending on how much you need, you can get it in up to 32oz containers.

  • Great against bermuda grass and broadleaf weeds
  • Selective weed killer
  • Post-emergence formula
  • A high concentration of active ingredients
  • Not suitable for all lawns

This formula is not just an efficient weed killer but also one of the best root killers. It’s been designed to control grass weeds, broadleafs, crabgrass, dandelion, clover, foxtail, as well as yellow nutsedge, among many others.

Once you apply the Spectracide HG-65703, you should see results in up to five hours. I also like waterproofing this formula has. It won’t take more than three hours for it to become waterproof.

Note that this is a broad-spectrum herbicide. As such, it may also kill some turfs. That’s the reason why I mostly recommend this as a spot-on treatment herbicide. And, if you don’t want to bother with concentrates, you can go straight for the Spectracide HG-65703 32oz spray bottle, which is premixed.

You can also get the spray bottles in packs of six if you have a large property that needs weed control. In terms of pricing, this is one of the more affordable solutions.

  • Ready to use
  • Affordable
  • Starts killing weeds within 5 hours
  • Waterproof after 3 hours
  • A broad-spectrum formula that may affect some lawns

If you’re looking for a natural herbicide, I’ve got just the thing. The Natural Armor Weed & Grass Killer is a highly concentrated herbicide made of natural, organic ingredients. I like that it doesn’t introduce chemicals into the environment.

It can treat upwards of 250 common weeds and wild grasses. Although it’s not the most waterproof formula, it comes already mixed and ready to use. Results should show in up to 24 hours as weeds dry out and start dying.

I like that this formula is safe to use around kids and pets, as well as some ornamental and edible plants. I would also recommend it if you don’t have the necessary tools for spot-on or broadcasting applications. The plastic bottle comes with a sprayer with an extension tube.

Do note that this is not an ideal solution for broadcasting applications. Since it’s not a selective herbicide, it may affect more of your lawn than you want. But, for spot-on treatments, it will work great, especially around flower beds.

  • Ready to use formula
  • Sprayer extension included
  • Broad-spectrum formula
  • Non-toxic and eco-friendly
  • May also kill a variety of lawn grasses

Whether you’re getting the 32oz or the 128oz Southern AG herbicide bottle, the name pretty much says it all. This weed killer has a classic dimethylamine salt formula, with an active ingredient concentration of 46.3%. It can take care of most broadleaf weeds, whether you use it on lawns, in parks, on ornamental turfs, and other areas.

This formula is concentrated, so you’ll have to be ready to mix it with water and use your tools to do proper spot-on treatments. In terms of ratios, you can use anywhere between two and three tablespoons per three to five gallons of water.

With this concentration range, you can quickly treat up to 1,000sq.ft. Of course, the exact ratio should be adjusted based on the type of broadleaf weeds. Larger weeds may require a higher concentration while you can dispose of others with a low impact formula.

If you don’t take into account the need for dispersal tools and a separate container for the post-mix formula, the Souther AG Amine 24-D Weed Killer is one of the most affordable concentrates on the market.

  • Broadleaf weed killer
  • Adjustable concentration
  • Safe to use on St. Augustine and other sensitive lawns
  • Safer than most glyphosate-based formulas
  • May take up to two weeks to show results

When you’re dealing with very tough weeds like yellow and purple nutsedge, kylinga, and others, you may want to consider using the Ortho Nutsedge Killer on your lawn. It is a highly potent formula that comes in 16oz and 32oz ready-to-use spray bottles.

Ideally, you would want to use this one on northern and southern grasses. That’s so the impact on your lawn would be minimal. It takes the solution up to two hours to become rainproof which opens up lots of options for applying the treatment.

Since it’s premixed and the bottle comes with an adjustable sprayer too, doing spot-on treatments should be very easy even if you lack landscaping experience. I also think that the Ortho Nutsedge Killer is reasonably priced.

Just be mindful when using your garden hose. Although you can make some adjustments on the sprayer, the dispersal pattern will still be quite narrow and dense so it won’t be ideal for broadcasting treatments.

  • Kills very tough weeds
  • Suitable for northern and southern turfs
  • Adjustable sprayer
  • Ready to use formula
  • Harmful to ornamental and edible plants

If you prefer natural herbicides and weed killers, and if you have a steady hand, then I recommend trying the Green Gobbler Vinegar Weed & Grass killer on your lawn. If you want to control crabgrass, clover, moss, dandelions, and most broadleaf weeds, this formula can help you do it fast.

It contains 20% acetic acid. That makes it highly potent, and you should be able to see results in a matter of hours. Weeds dry very quickly, although this particular type of weed killer may not always target the root system.

Although non-toxic, it’s still a broad-spectrum desiccant. It means that broadcasting applications are out of the question since you can just as quickly kill your lawn with this Green Gobbler weed killer. But, if you keep your spot-on treatments accurate, close to the root of the weeds, then you should have no problems.

And, don’t think for a second that this is just another table vinegar weed killer. The formula is much more powerful, hence why it takes mere hours to dry out weeds completely.

  • Non-toxic formula
  • Highly potent and quick drying
  • Broad-spectrum non-selective herbicide
  • Ideal for spot-on treatments
  • Not suitable for broadcasting applications

This BioAdvanced weed killer can make short work of over 200 broadleaf weeds. You can find it in 24oz, one gallon, and 1.3-gallon containers. I recommend the latter as it also comes with a sprayer attachment for accurate applications.

The formula becomes waterproof after just one hour after application. That means that it dries quickly and that it also has a fast absorption rate. Since it will get down to the roots fast, it makes sense to see visible results in a matter of hours.

I also like the Smarttrack red marker feature. This added component will allow you to see all treated areas distinctly. But, the marker will eventually fade with sunlight. It’s not a nighttime marker by any means.

  • Smarttrack red marker
  • Sprayer attachment included
  • Ready-to-use mixture
  • Potent broadleaf weed killer
  • Can’t be used on St. Augustine grass and other warm-season lawns

Types of Treatments and How to Apply Them

There are two types of treatments you can apply on your lawn. There’s the spot-on treatment and the broadcasting treatment.

A spot-on treatment is something you do for small patches of lawn that are affected by weeds. You can use a narrow spray pattern or pour the herbicide close to the weed roots, without getting it to touch the surrounding grass.

This way, the herbicide won’t transfer to the grass, even if it reaches the root system. Broadcasting treatments are quite the opposite. You’re supposed to apply them over large patches of lawn. But, to use this kind of control herbicide, you’ll have to make sure you’re using a selective formula that won’t target your type of lawn.

In terms of accessories and tools, there are a bunch you could use. There are wand applicators, spray nozzle extension tubes, garden hose sprayer heads, and so on. Some herbicides come premixed and in sprayer bottles.

Others will require a garden hose sprayer head for broadcasting applications. Others, again, can be poured directly from a tiny spout. They’re all situational, and the one you need will depend on your particular weed problem.

Why Natural Weed Killers Might Be More Difficult to Use

People have been using boiling water and vinegar-based DIY herbicides for a very long time. Why? Because they’re very efficient. For example, vinegar is a natural desiccant that can dry weeds very fast, cleaning patches of lawn in record time.

But, as good as table vinegar solutions are, natural herbicides use a much higher concentration of acetic acid. That means that they’ll work much faster and that they will also be effective against more resilient types of weeds.

That said, it’s not the easiest or safest thing to do, using vinegar-based herbicides on your lawn. Because vinegar is a natural desiccant, it can, and likely will kill your garden too. Therefore, you can’t use it for broadcasting applications.

Even as a spot-on herbicide, it won’t be risk-free due to how quickly it dispatches healthy plants. Does it have any benefits? Sure, it does. This type of herbicide won’t contaminate the soil, water sources, nor will it introduce chemicals that are toxic to humans and animals into the environment.

So, it all boils down to what you’re trying to achieve. If you do decide on using a vinegar-based herbicide, make sure you’re not getting it for large-scale applications, and that you can spray it or pour it at a controlled rate with a high degree of accuracy.

Selective vs Non-Selective vs Broad Spectrum Weed Killers

Selective weed killers have formulas that target particular species and offshoots of said species of weeds and grasses. The most commonly available selective weed killers target broadleaf weeds. That said, broadleafs also include some non-weed greens. That means that not all broadleaf weed killers are safe to use on all turfs and lawns.

Non-selective weed killers don’t care about anything. They’re designed to kill most plant life they come across. The list includes weeds, grasses, and even some plants. Just like most other weed killers, non-selective formulas can also be absorbed quickly and transported down to the root system for complete clearance.

You can use broad-spectrum weed killers for targeting a variety of weeds. You could also call them selective; it’s just that they’re selective for more than one type of weed.

The terminology is not always that important as more and more herbicide manufacturers now list a complete list of weeds the formula affects, as well as grasses that are also vulnerable to it.

The Impact of Residual Control

The residual control effect or persistence of a herbicide refers to the period the formula remains active after application. Many of the common herbicides sold today can protect your lawn for a few weeks after application. It means that they stay active in the soil and prevent new weeds from sprouting.

But why is this particularly important? Because once you clear your lawn of weeds, naturally, you will want to reseed it and make it look great again. Knowing the persistence of a herbicide will help you avoid planting seeds too early.

Even though some herbicides are selective and you can use them for broadcasting applications, this doesn’t mean that you can reseed the cleared areas right after you’ve treated them. The herbicide may be strong enough to affect the new seeds.

Or, it could take a couple of weeks until the herbicide gets rid of the root system entirely. Note that just because the weeds have dried out and died on the surface, it doesn’t mean that the root system has also died.

When It’s Best to Apply Treatments on Your Lawn

Correct timing is another situational thing that depends on the type of weeds growing on your lawn, the resilience of your garden, and of course, the herbicides.

The two most common types of herbicides are pre-emergence and post-emergence herbicides. The former is there for situations before the weed seedlings pop out of the ground.

The post-emergence herbicides can and should be used on mature weeds. Unlike pre-emergence herbicides, these can be absorbed both through foliage and through the root system.

Note that there are also pre-plant herbicides. These are almost always non-selective and can kill all sorts of seeds. They are supposed to be used before planting season, but these aren’t as common and easy to find. And, most of them require experience to use safely.

Time to Take Your Lawn Maintenance to the Next Level

A lot goes into picking the best weed killers for maintaining your lawn. You first have to identify the weeds, know your grass, and correctly estimate the application timings. After all that, you are ready to choose an appropriate weed killer safely.

That said, the last part should be straightforward now that you’ve seen some of the most efficient herbicides for most common applications and weed problems.

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