10 Best Weed Killers for Lawns in 2021 – Reviews & Top Picks
Weed killers can help maintain your landscape or garden and prevent unsightly and noxious plants from overtaking the plants you actually want to grow. There are many options of weed killers on the market, some better than others.
People have been fighting weeds in gardens and flower beds for centuries. The first weed controllers were sea salt, industrial by-products, and oils. The first broad-leaf herbicide was developed in France in the late 1800s. Now there are almost too many herbicides to name, with more being developed every day.
Since there are many types of weeds, one pesticide won’t kill every single one. Our top 10 list offers a variety of pesticides, from common ones to unique organic solutions, so you can choose the right weed killer for your garden or lawn.
A Quick Comparison of our 2021 Favorites:
|Best Value||Southern Ag||
|Roundup Max Control 365||
The 10 Best Weed Killers for Lawns:
1. Preen 2464083 Garden Weed Preventer – Best Overall
This weed killer is a pre-emergent granular herbicide, which means it kills the weed before it germinates. So, be aware that it does not kill existing weeds. You need to pull any existing weeds and grasses before applying Preen to the ground.
Preen’s active ingredient is Treflan, and the carrier agents are recycled newspapers and corn cobs. The 31.1-pound bag covers 5,000 square feet. You can apply it in the spring, summer, or fall, and it’s guaranteed to work for up to three months, though you can re-apply every nine to 12 weeks if you wish. We found ease of use to be one of its best advantages — no need for protective equipment besides gloves.
Preen won’t build up in the soil, leach into groundwater, or wash away with rain. It is safe to use around 200 established vegetables, trees, shrubs, and flowers, as well as certain edibles. We recommend reading the included pamphlet for the entire list.
As with any weed killer, there are precautions. Do not use on lawns or flower seeds until the plant is at least two to three inches tall. It is safe for humans and pets after the treated area is dry from the rain or first watering. It is harmful to aquatic life, so do not apply near ponds or other waterways if there is a chance of runoff. It also can’t be used where chickens, cows, or other animals graze.
2. Southern 00203 Weed Killer – Best Value
Ag amine is an auxin type of herbicide that causes the part of the plant that carries the water and the nutrients to divide and grow without stopping, essentially causing destruction to the plant. It works on broadleaf and woody plants and is not for flowering ornamentals and food crops.
They sell Ag amine concentrated, and it has an economical use rate of one to four pints per acre. To re-constitute, place five tablespoons in five gallons of water — this will cover approximately 1,000 square feet when applied with a low-pressure sprayer.
You should not apply around bodies of water, as it can contaminate the water, and children and pets should be kept out of treated areas until it has dried. When spraying, do not inhale any of it, and wear protective clothing to prevent skin and eye irritation, breathing problems, and headaches.
While this product is less expensive, it is not in the number-one position because it is not as easy or safe to apply.
3. RM43 76501 Plus Weed Preventer – Premium Choice
This weed killer contains two herbicides and a surfactant. The two herbicides are glyphosate, which kills broad leaf weed and grasses, and imazapyr, which kills a wide range of terrestrial plants, including grasses, woody species, and riparian and aquatic species. It is labeled as a pre-emergent and a post-emergent.
RM43 can sterilize the ground for up to one year, or you can spot treat to control specific plants. It is ideal for fence rows, gravel paths, sidewalks, and driveways. If you treat a large area, you won’t be able to plant anything in that spot for at least a year. For example, if you use it to kill an area of lawn, you cannot re-seed the grass until next year because RM43 will prevent the grass seed from germinating.
This product comes in a concentrated liquid form that can treat up to 43,243 square feet in 2.5 gallons. It is rain fast within two hours of application and safe for children and pets once it has dried.
RM43 is not good for crops nor is it pet or livestock friendly. When spraying, do not come into contact with the solution or spray near water, as it will contaminate the water source.
4. Green Gobbler Vinegar Weed & Grass Killer
A natural and organic weed killer, the Green Gobbler is a nice alternative for those more environmentally conscious. It is certified by the Organic Materials Review Institute (OMRI), which ensures that products meet organic standards and are checked for prohibited ingredients.
This weed killer derived from corn is 20% acetic acid (vinegar) but four times stronger than table vinegar. It is biodegradable and ready to use, meaning that no mixing is required. It’s also a non-selective herbicide, which means you will want to avoid spraying it on healthy grass and desired plants to prevent damage.
It comes with a trigger spray that you attach directly to the bottle. Avoid spraying before or during rainfall, since this will dilute the solution and make it ineffective. You shouldn’t spray directly into water, since it can negatively affect aquatic plants, but near water is fine because it is quickly absorbed and neutralized by the soil. For best results, spray on a sunny day when the temperature is above 65 degrees.
You may need to apply more often to get the desired effect — one gallon will cover 1,200 square feet. We found that the sprayer nozzle is not high quality nor durable. On the positive side, it comes with a 30-day money-back guarantee.
5. Roundup Max Control 365 Weed Killer
The main ingredient in Roundup 365 is glyphosate, which kills grass and broadleaf plants. It also contains 18% Imazapic, which has pre- and post-emergent control. This form of Roundup will kill and prevent weeds and grasses for up to 12 months.
It kills the root and prevents new seeds from germinating. You’ll have to wait one year to plant anything where you have sprayed. It is good for fence lines, graveled areas, and alongside foundations and patios.
The 1.3-gallon container comes with a wand sprayer and will cover approximately 1,300 square feet. Once you spray, it will be rain proof within 30 minutes, and you will see visible results within 12 hours. They offer a consumer guarantee, so if you are not satisfied, you can return the product for a full refund.
Protect yourself from exposure to this herbicide by wearing protective gear to keep it off your skin and out of your lungs. It can contaminate water sources, so do not spray near water. Wait until it has dried completely to allow pets or children near sprayed areas.
6. Compare-N-Save 016869 Grass & Weed Killer
This weed killer contains 41% glyphosate, so it does a good job at eliminating pesky broad-leafed weeds and grasses. It is not as strong as the Roundup 365, but it will kill weeds effectively for a shorter time. It is not an extended control herbicide and won’t prevent seeds from germinating, so you will have to spray more than once per year.
This comes concentrated and will have to be mixed with water before applying. This one-gallon jug will make 85 gallons of spray and cover up to 25,000 square feet. It is rainproof within two hours, but the manufacturer recommends waiting 24 hours before the treated area becomes wet. You should see visible results within two to four days.
Kids and pets can go on the treated area once the solution has dried. As with other glyphosates, it will contaminate water and requires protective gear with extra precautions when spraying.
7. Ortho Nutsedge Killer for Lawns
This is a great option for killing tough weeds such as Nutsedge and 50 other varieties. Ortho formulates this weed killer especially for northern and southern grasses, and it comes as a ready-to-spray solution, so you just need to connect it to a water hose.
It contains .05% Sulfentrazone, which is a post-emergent weed killer that disrupts the plant membranes and stops photosynthesis. The 32 ounces cover approximately 5,000 square feet. It is rain proof within two hours, and you can see results as soon as two days.
This herbicide works best when applied to weeds less than three inches high, so hardier weeds may need more than one application to kill them effectively. Care should be taken when spot treating, as it can kill your ornamentals.
When spraying, don’t forget to protect your skin — it can cause skin irritation upon contact.
8. PBI/Gordon Speed Zone Weed Killer
This is a four-way blend containing selective post-emergent herbicides that kill broadleaf and other lawn weeds, and it won’t harm lawn grasses. It is more soluble and will quickly absorb into the plant, causing it to die quicker.
In fact, you can see visible results within a few hours of spraying, and you can even reseed the area as soon as two weeks. It is rain fast within four hours of application, and it’s also pet safe if you follow the directions on the label, basically only allowing pets onto the treated area once it’s dry.
This herbicide comes concentrated, and the 20-ounce bottle, once mixed with water, will cover 14,000-18,000 square feet. As mentioned with the other weed killers, protect yourself from skin exposure and inhalation. It is not safe for edibles or aquatic life and will contaminate water sources.
9. Spectracide 96017 Weed & Grass Killer
A non-selective herbicide with the main ingredient being 12% Diquat Dibromide, this weed killer causes injury only to the parts of the plant to which it is applied. Nevertheless, it is a quick-acting solution, and you will see visible results within three hours of spraying. Since it dries quickly, it’s rain fast within 15 minutes.
This product is best for patios, walkways, and fence lines. It comes in a ready-to-use spray bottle that requires it to be connected to a water hose to function. The one-gallon container will treat 3,000 square feet.
Since it is non-selective, take caution where you are spraying, since it will damage anything it comes in contact with. Do not use on edible crops, and don’t mow, cut, or disturb any sprayed vegetation for seven days after spraying. It is safe to reseed seven days after treatment.
Protective equipment is essential, and Spectracide can easily contaminate water sources. Don’t allow it to run into storm drains, drainage ditches, gutters, or surface water.
10. OrganicMatters Natural Weed Killer
This natural weed killer is organic, though it is not certified as such. It is non-selective, with the main ingredient being acetic acid (vinegar). You can start to see results within 24 hours of application, though with this solution, you will have to apply it frequently to keep the weeds at bay, since it is not a pre-emergent.
The one-gallon jug will cover approximately 1,000 square feet, and it comes with a spray attachment for ease of use. For best results, spray when it is warm and sunny. This solution dries fast and is safe for pets once the area is completely dry.
Basic protective equipment is needed, though take care not to get near the eyes, as it can cause irritation. There is a 30-day satisfaction guarantee, so if you don’t like the product, you can send it back for a full refund.
When buying herbicides, it’s in your best interest to know the different types/categories so you can purchase the correct herbicide for the particular plant you want to kill. All herbicides come with safety precautions and instructions for disposal, so this buyer’s guide will further discuss how to stay safe when using weed killers.
Types of Herbicides
There are two classes of herbicides: selective and non-selective. These two classes have three characteristics: emergence, translocation, and persistence.
Selective: They will only kill a certain type of plant, leaving others unaffected. These are ideal because you can kill a weed living in or near your ornamentals and not damage them.
Non-selective: This herbicide is formulated to control/kill all types of plants, from weeds to ornamentals. It is effective in clearing a piece of ground along fence lines or gravel driveways.
Emergence: Pre-emergents target seedlings before they germinate. Apply this type of herbicide two to three weeks before germination. Post-emergents will only affect the growing plant (one that has already germinated). Apply this herbicide to the leaves of the plant.
Translocation: Translocated herbicides works their way through the internal system of the plant to kill it, while contact herbicides are applied to the leaves to kill on contact.
Persistence: This describes how long the herbicide remains active after application. Non-persistent do not prevent further weed growth, while persistent will kill everything and prevent regrowth.
- Identify what type of weed you want to kill. If you are having trouble, there are many weed identification tools available online.
- Do you want to kill certain weeds or grasses? Or do you want to kill everything in one location?
- How big of an area do you want to treat? This will determine how much you need to buy. Know if it is concentrated or pre-mixed.
- It’s good to know how fast it dries (if liquid) and how long it takes until it is rainproof. You don’t want to treat an area only to have rain wash it all away.
- Organic options are available, which can be certified or non-certified. They will typically be the safest to use.
- Is it safe to use near edible plants?
Safety With Herbicides
There’s no reason for excessive and unnecessary chemical exposure. Therefore, it is important to follow safety precautions when using herbicides to protect yourself, family, and pets. This section will help you understand the basics of handling herbicides safely.
- Always read the label, as it contains important information about the product. It will cover everything you need to know about using that herbicide. Remember, each one is different — some may be more toxic than others and require greater precautions.
- Don’t just read the label — follow the instructions on the label too. Know the difference between the three signal words that describe the level of toxicity: caution, warning, and danger.
- It is a legal requirement to wear the protective equipment listed on the label. You can always wear more than what is listed, just don’t wear less. Always pick the material that will offer the best protection from the chemical.
- There are four exposure contact points that need protection:
- The skin: Cover with non-absorbent materials.
- Breathing in vapors: Wear a mask.
- Through the eye: Wear goggles.
- Through the mouth (by swallowing): Wash hands thoroughly.
Herbicides are beneficial because they keep weeds at bay and prevent them from overtaking your vegetable garden, landscape, or yard. It is important to learn how to use them correctly and pick the correct one for the weed you want to control.
Our number-one pick is the Preen Garden Weed Preventer. As a pre-emergent, it kills weed seeds before they have a chance to become a nuisance. The best value is the Southern 2, 4-D, since it offers broadleaf and woody plant control while being economically priced. For an herbicide that can kill and prevent weeds for up to one year, the RM43 is our premium choice.
Weeds are unsightly and can be difficult to control, but herbicides can make your job easier. With many choices available on the market, we hope that we helped you find the right one that will be effective and affordable, helping you keep your lawn and garden beautiful throughout the year.
- A Quick Comparison of our 2021 Favorites:
- The 10 Best Weed Killers for Lawns:
- 1. Preen 2464083 Garden Weed Preventer – Best Overall
- 2. Southern 00203 Weed Killer – Best Value
- 3. RM43 76501 Plus Weed Preventer – Premium Choice
- 4. Green Gobbler Vinegar Weed & Grass Killer
- 5. Roundup Max Control 365 Weed Killer
- 6. Compare-N-Save 016869 Grass & Weed Killer
- 7. Ortho Nutsedge Killer for Lawns
- 8. PBI/Gordon Speed Zone Weed Killer
- 9. Spectracide 96017 Weed & Grass Killer
- 10. OrganicMatters Natural Weed Killer
- Buyer’s Guide
- Types of Herbicides