Buying guide for best weed killers
The ultimate buzzkill for any lawn or garden is unquestionably weeds. Not only do they make everything look unkempt, but they also compete with your grass and plants for sunlight, water and nutrients. Getting rid of them gives your plants what they need to thrive and makes your garden or lawn look way more presentable.
You can certainly pull away pesky weeds by hand, but you'll get tired quickly if you have to deal with a lot of them. Not only that, you probably won't pull them by the root, which means you'll see them again in just a few weeks.
That's why a good weed killer can be such a game-changer. There are several brands and concentrations to choose from, but once you understand the differences between the main types of weed killers and what they're designed to do, it's easy to pick the best option for your yard or garden. Our favorite is Roundup Max Control 365, which starts working right away and prevents weeds for up to a year.
How weed killers work
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.
Where to use weed killers
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.
All weeds
If you want to kill all weeds, grasses, and other plants in a large area, choose a product designated for grass-killing. However, apply it carefully or it could kill nearby plants you’d like to protect.
Lawn protection
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.
Garden protection
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.
Woody plants
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.
Weed killer 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.
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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.
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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.
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Direct: You apply some of the newer weed killer gels directly by “painting” it onto the leaves.
Weed killer prices
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 a better price 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.
FAQ
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 appear 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 find out how it works on future weed growth.
Our expertise
Kevin Luna has written numerous articles on tools and gardening supplies for BestReviews. Having done his fair share of gardening and lawn care over the years, he has strong opinions on the best ways to get rid of weeds for good.
Kyle Schurman covers a wide range of products, from sports equipment and tools to laptops and smartphones, as a writer for BestReviews. He loves helping consumers find products that make their lives easier.
