Effective, fast-acting, long-lasting. Kills weeds and grass within hours and prevents new growth for nearly a year. Concentrated.
Somewhat pricey, and it doesn't go as far as others on our list - but it is more effective. Not available for purchase in CA due to herbicide regulations.
Works fast. Good for hard-to-reach weeds/grass in cracks/crevices. Can be used safely around flowers, shrubs, and other vegetation.
Doesn't last as long as concentrated formulas. Does not kill existing weeds.
Effectively kills most weeds and unwanted grass. Highly concentrated for superior savings; 1 gallon makes up to 85 gallons of mix. Some users claim one jug lasts for up to 2 years.
Doesn't work overnight; takes several days to a week to kill weeds. Doesn't prevent new weeds. May not kill some robust weeds.
Kills broadleaf weeds such as dandelions, chickweed, and poison ivy without harming grass. Works within days. Concentrated; 2 - 3 tablespoons treats up to 1,000 sq. ft.
Not recommended for use on windy days, as it can drift and damage delicate plants. Chemical odor is strong and may linger for a few days.
A powerful weed killer that tackles hard-to-kill growth. Also effective at killing vines, brush, and some stumps.
Results aren't instant; resistant weeds take a few days to several weeks. Care must be taken to keep it from drifting to unintended plants. Some owners say their dogs tried to lick treated areas. Not concentrated.
We purchase every product we review with our own funds — we never accept anything from product manufacturers.
No one likes the look of weeds in a lawn, flower bed, or vegetable garden. Beyond looks, weeds steal valuable nutrients and sunlight from the plants you want to grow. Killing the weeds can help your other plants stay healthier.
It’s tough to pull stubborn weeds, and it’s frustrating when the root breaks in half, leaving the weed to grow back later. Instead, you can apply a weed killer, which uses chemicals to kill the weeds over time.
With so many different brands and types of weed killers on the market, picking the right option isn’t easy. At BestReviews, we can help you make the smartest choice for your situation.
We pride ourselves on the detailed research we perform in each product category we cover. We seek to provide readers with information they can trust to help them make smart buying choices. Because we never accept free samples from manufacturers, you can be assured that our selections and product reviews remain free of bias.
Check out our top five weed killer recommendations above, or read our shopping guide for more general information about these products.
Whether you use a powder, granular, liquid, or gel weed killer, the products all tend to work in a similar manner: the chemicals in the weed killer stick to the leaves of the weed, which then absorb the chemicals.
Once the plant absorbs the weed killer, the chemicals destroy the weed’s structure. The weed carries the chemicals to its root system, too, hastening the demise of the weed. You’ll notice spots and browning on the leaves a day or two after applying the weed killer. The plant will begin to droop one to three days after application. The plant should die three to seven days after application.
To ensure the weed killer only targets the weeds you want to kill, spray on a windless day.
Some weed killer products will kill any kind of plant, not just weeds. Sometimes, you may want to kill weeds in an area but not the other plants growing there. For example, you might want to kill the weeds in your lawn while keeping the grass healthy.
Manufacturers have created a host of different weed killer products aimed at keeping certain plants safe. Other products will eliminate all plants, including weeds.
If you want to kill all weeds, grasses, and other plants in an large area, look for a grass-killing designation on the product. However, apply it carefully or it could kill nearby plants you’d like to protect.
Certain weed killer products are sold concentrated, meaning you must mix the chemicals with water before application.
Some types of weed killers, such as granular and powder, do not kill grasses, even if they come in contact with them. The chemicals in these products only stick to broadleaf plants. You can apply these weed killers to dandelions in your lawn without harming the grass.
If you have a certain type of weed you want to kill, read the instructions. Each product includes a list of the weeds it kills.
Because most flowers and vegetables have broad leaves, using a weed killer in a garden is tricky. The chemicals will destroy broadleaf flowers and vegetables just as easily as weeds.
Your best option is to use a weed and grass killer product but apply it carefully. A gel type of weed killer works well in this case. Or use a sprayer very precisely on a day with no wind.
Most weed killer spray nozzles have different settings. Pick the best one for your application needs.
The most powerful types of weed killers work on woody plants, such as brush or ivy. These weed killers will also kill any other types of plants, such as broadleaf weeds and grasses. You want to apply this type of weed killer very carefully. Avoid using it on a windy day.
Depending on the weed killer, you will have to wait a few days to several months to plant anything new in the area after application.
Manufacturers have created a host of options for applying weed killer products. Some of these methods are more precise; others allow you to apply the product more quickly. Some weed killer containers are sold with the application device attached. Others require you to supply your own application device.
Sprayer: You apply most liquid weed killer products with a sprayer. If you’re applying the chemicals over a huge area, you might use a large sprayer pulled behind an ATV or lawn tractor. For smaller applications, you can carry a container and hold the sprayer in your hand. Air pressure feeds the liquid into the sprayer, and you press a trigger to apply the liquid.
Spreader: You use a drop spreader to apply powder or granular weed killer products. This is a common way to quickly apply fertilizer and weed killer mixed together on a lawn or other large area. Spreaders don’t work for applying weed killer to individual weeds.
Direct: You apply some of the newer weed killer gels directly by “painting” it onto the leaves.
Consider a gel weed killer if you need to precisely apply the chemical in a flower bed.
Comparing the costs of different liquid weed killers can be a challenge. Even if two products ship in the same container size, the weed killers may be nothing alike. When comparing prices, calculate the cost per gallon of ready-to-use weed killer. For concentrates, calculate the cost of the concentrate based on the number of gallons of diluted product you can make. Then compare that amount to the ready-to-use product.
Concentrate: For concentrated weed killers, you must add water to dilute the chemical before application. This gives you better value per ounce than it may appear initially because you’ll get more applications per bottle than with a product that already contains water. Note that you’ll have to supply your own sprayer, adding another $10 to $25 to the cost, but you can use the sprayer dozens of times if you care for it properly.
Price: Concentrated products cost roughly $3 to $10 per gallon diluted.
Ready-to-Use: A ready-to-use weed killer requires no dilution with water. Most of these containers have a sprayer or other application apparatus built into them, further simplifying the application. Gel products fit into this category. You will pay extra for the convenience of a ready-to-use product.
Price: Ready-to-use weed killers cost roughly $8 to $20 per gallon.
Powder and Granular: Because powder and granular weed killers also include fertilizer, they’re used for a different purpose and not really comparable to liquid weed killers when it comes to price.
Price: Powders and granular products cost about $5 to $12 per 1,000 square feet of lawn.
Q. How will I know if the weed killer is working?
A. Most weed killer products show progress within several hours, although some require up to 24 hours. When the weed killer is working, you’ll notice brown spots on the weed’s leaves, and the plant will droop and look unhealthy. Check the label on your weed killer product for the exact period of time between application and results.
Q. Should I apply weed killer before it rains, after it rains, or wait for a dry day?
A. All weed killers are a little different, but most sprays are best applied on hot, dry days. Because it’s difficult to predict the weather, you may inadvertently apply the weed killer right before it rains. For most weed killers, rain won’t wash off chemicals that have been on the weeds between 30 minutes and a few hours. Read the instructions for more specific information.
Q. Are weed killer products safe?
A. As long as you follow the instructions, you can use these chemicals safely. You should avoid prolonged exposure to skin for most of these products. Don’t let the chemicals splash into your eyes. And don’t ingest the chemicals. As long as you follow the instructions, kids and pets typically can play in the area a few hours after application.
Q. Will weed killers prevent weeds from growing back in the future?
A. Some weed killer products eliminate the weeds that are growing now, but they don’t keep more weeds from springing up later. Some products are designed to apply a barrier that stops new weeds from starting. Carefully read the instructions and recommended uses for any weed killer you’re considering to see how it works on future weed growth.
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