To determine the best weed killers, we researched dozens of the most popular options, considering their active ingredients, effectiveness, and ease of use. We also paid attention to whether the products were designed to kill weeds, prevent weeds, or both. In addition to Dr. M-Curtis, we also spoke to Michael Augaitis, lawn care expert and owner of Florida Gardens Lawn and Shrub Care, and Stuart Mackenzie, horticulturist and expert at Trees.com, to learn more about how weed killers work, when to use them, and what to consider before buying them. The first thing you should do before shopping for a weed killer is identify the types of weeds you have growing in your yard. Then, you can “determine your goal and use the information to select a weed killer,” says Dr. M-Curtis. Our top pick, Scotts Turf Builder Triple Action, is a best-in-class option, thanks to its ability to kill and prevent specific weeds while fertilizing grass on your lawn. Keep reading for more of the best weed killers and preventers on the market, plus expert tips for buying and using weed killers.
Our Top Picks
Best Overall Weed Killer: Scotts Turf Builder Triple Action Best Natural Weed Killer: Green Gobbler 20% Vinegar Weed and Grass Killer Best Weed Killer for Lawns: BioAdvanced All-in-One Lawn Weed Killer Concentrate Best Weed Killer for Flower Beds: Roundup Landscape Weed Preventer Best Weed Killer for Vegetable Gardens: Preen Natural Vegetable Garden Weed Preventer Best Weed Killer for Patios: Spectracide Weed and Grass Killer With Extended Control Concentrate
Scotts Turf Builder Triple Action earned the top spot on our list because it does more than the average weed killer. This product kills pesky lawn weeds and prevents unwanted grassy weeds from growing. And it does both of these things while fertilizing your lawn at the same time, eliminating the need for a separate fertilizer. This three-in-one approach sets it apart from other popular weed killers and preventers, making it a particularly convenient way to clean up your lawn. Although it’s important to note that this weed killer is intended for lawn care, not flower beds or gardens. Since this is a selective weed killer, you don’t have to be precise when applying it. Instead, you can spread it across your lawn and trust it to kill specific weeds while preserving the grass you want. When used correctly, the so-called “weed and feed” will kill common weeds like dandelions, clover, chickweed, and more. It can also prevent grassy weeds, like crabgrass, from growing for up to four months (although it will not kill any existing crabgrass). Product Details:
Active Ingredients: Dicamba, pendimethalin, and 2,4-DPre-Emergent: YesPost-Emergent: YesSelective: YesTargeted Plants: Dandelion, clover, dollarweed, ground ivy, chickweed, henbit, plantain, English daisy, crabgrass, barnyard grass, fall panicum, foxtail, and annual bluegrass Application Style: Broadcast spreader (sold separately)
Green Gobbler’s weed killer is an all-natural way to prevent weeds from growing in your yard. Its formula contains two simple ingredients: vinegar and water. But since the mixture is so concentrated, you can expect the weed killer to be about four times stronger than the table vinegar in your pantry. This treatment works by drying out the weeds it touches, a process that typically kills them within 24 hours. This makes it an extremely effective natural weed killer. But there’s one important thing to note: The Green Gobbler weed killer will prevent all kinds of seeds from growing roots—including any seeds you intentionally planted if you accidentally spray them. (After all, vinegar doesn’t know the difference between weeds and vegetables.) This makes the application process less convenient than the selective weed killers on this list. But if your top priority is using all-natural ingredients, this is a necessary tradeoff—the product is one of the few all-natural and organic weed killers out there. And since it comes inside a tank sprayer, it should be easy to target unwanted weeds while avoiding the plants you want to keep. Plus, it’s safe to use around children and pets when used as directed, unlike most chemical weed killers. Product Details:
Active Ingredients: VinegarPre-Emergent: NoPost-Emergent: YesSelective: NoTargeted Plants: AllApplication Style: Tank sprayer
Weeding by hand can be frustrating. But spraying individual weeds with weed killer can be just as tedious, especially if your yard is big. So when you’re working with a large space, like a lawn, a selective weed killer comes in handy. And that’s why we recommend BioAdvanced’s All-in-One Lawn Weed Killer for the job. The weed killer is designed to kill 217 common yard weeds before and after they’ve emerged, including crabgrass. It’s a great option for killing fully grown weeds and for stopping younger weeds in their tracks. This dual approach makes the BioAdvanced weed killer a great pick for your lawn, and its easy application method makes it an even better buy. Simply attach it to your garden hose and turn the water on, then use your thumb to activate the sprayer. Since the weed killer is selective, you can spread it freely across your yard to clean up weeds without harming your lawn. Product Details:
Active Ingredients: 2,4-D, dimethylamine salt, Quinclorac, and dicambaPre-Emergent: YesPost-Emergent: YesSelective: YesTargeted Plants: Dandelion, clover, thistle, chickweed, crabgrass, and moreApplication Style: Tank sprayer
Hoping to keep weeds out of your flower beds? Roundup’s Landscape Weed Preventer is a great first line of defense. While this product won’t get rid of existing weeds, it will kill weeds before they can grow in the first place, making your flower beds much easier to maintain in the long run. The treatment contains pendimethalin as its active ingredient, and it acts as a “weed barrier,” so it stops common weeds from growing wherever you sprinkle it. This makes it a great pick for people who have flower beds and intricate landscaping. You can spread the treatment around your plants and flowers, and it will keep weeds at bay for up to six months. The Roundup weed preventer is another option on this list that’s selective, so it shouldn’t harm your prized flower beds or landscaping, even if you’re a little imprecise when applying it. It also has a built-in applicator, which means you can shake out the treatment directly from the bag. Product Details:
Active Ingredients: PendimethalinPre-Emergent: YesPost-Emergent: NoSelective: YesTargeted Plants: Clover, chickweed, crabgrass, foxtail, and moreApplication Style: Shaker bag
RELATED: The 10 Best Raised Garden Beds for Planting Herbs, Flowers, Veggies, and More When controlling weeds in a vegetable garden, you want a weed killer that’s all-natural and safe for use around food and herbs—and Preen’s Natural Weed Preventer fits the bill. This weed killer contains a single ingredient—corn gluten meal—which prevents germinating weeds from growing roots. You’ll have to be proactive though: This product stops weeds from growing in the first place, but it won’t kill any of the existing weeds in your vegetable garden. The Preen weed preventer is another all-natural product that isn’t selective, so you have to make sure you only apply it to areas with weeds. Otherwise, you might find that the treatment stops your veggies and herbs from growing, too. But, when used correctly, the product works for up to four weeks, so you only need to apply it every month or so. And if you maintain an organic vegetable garden, it’s available in an organic version, too. Product Details:
Active Ingredients: Corn gluten mealPre-Emergent: YesPost-Emergent: NoSelective: NoTargeted Plants: AllApplication Style: Shaker
Fast-acting, effective, and easy to use, Spectracide’s Extended Control Weed and Grass Killer is a great option for patios, sidewalks, driveways, and other paved areas. The product relies on several active ingredients to control weeds, and it’s a very effective formula. It can kill existing weeds in as little as three hours and it can prevent new weeds from growing for up to five months. And you don’t have to worry about inclement weather right after application—if it rains more than 15 minutes after application, the precipitation won’t wash away the treatment. Since this Spectracide weed killer isn’t selective, it should effectively knock out any plant or weed it touches. This may sound like a negative—if the product isn’t selective, you usually have to be careful where you spray it—but remember that you’re applying it on pavement. Anything growing out of your patio or driveway likely wasn’t supposed to be there in the first place. That’s why we still think using the Spectracide weed killer is an efficient way to clean up paved areas. Product Details:
Active Ingredients: Diquat dibromide, fluazifop-p-butyl, dicamba, dimethylamine salt, and oxyfluorfenPre-Emergent: YesPost-Emergent: YesSelective: NoTargeted Plants: AllApplication Style: Tank sprayer
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How to Shop for Weed Killers Like a Pro
Ingredient List
Weed killers can use a range of different ingredients—some natural, some not. If you’re curious about what’s inside a weed killer, be sure to check both its active ingredients list and its other ingredients list. We made it easy for you by listing the active ingredients for each weed killer we recommend (some common examples are dicamba, pendimethalin, vinegar, and 2,4-D). Unfortunately, most companies don’t disclose full lists of the other ingredients in their formulas, which makes it difficult to determine everything that’s in a given weed killer.
Pre-Emergent vs. Post-Emergent
Weed killers can be pre-emergent, post-emergent, or both. If a weed killer is pre-emergent, it will help you control weeds before they start to grow. (These are usually called weed preventers.) Post-emergent weed killers, on the other hand, will help you kill existing weeds in your yard. Finally, if the weed killer is pre-emergent and post-emergent, it will do both of these jobs.
Selective vs. Non-Selective
Some weed killers are selective, meaning they’re designed to kill certain weeds without harming other plants. Others are non-selective, so they’ll kill any plant they encounter. Selective weed killers are generally more convenient than non-selective weed killers: You don’t have to be super precise when applying them, and they won’t harm other vegetation such as landscape flowers or plants. But they’re also engineered, so people who want an all-natural solution should pick a non-selective weed killer instead. If you choose to use a selective weed killer, check to see which weeds the product is designed to target. (You can usually find a list on the product label.) Make sure the formula you’re considering can help kill or prevent the specific weeds that you have in your yard. You’ll also want to confirm that it won’t kill grass on your lawn and any plants you want to keep.
Application Style
There are many different ways to apply weed killer to your lawn and garden. Some of the most popular methods include traditional spray bottles, shaker bags, tank sprayers, and broadcast spreaders. Generally speaking, targeted options (like traditional spray bottles) are more precise but not as convenient to use. You can easily treat weeds with a spray bottle, but it may take a while to get through your entire yard. This makes weed killers with targeted application styles a great option as long as it’s a non-selective formula. Less targeted application styles (like broadcast spreaders) make it harder to be precise, but they’re easier to use. You can cover a lot of ground quickly, but you may end up spraying everything in your yard. Because there’s a greater risk of accidentally treating flowers or plants that you want to keep, these application styles are much better when you’re using a selective weed killer.
Questions You Might Ask
How do weed killers work?
There are two different kinds of weed killers—contact weed killers and systemic weed killers—and both work by disrupting the normal growth of a plant. “When sprayed on a weed, [contact weed killers] cause the membranes of the tissues…to be disrupted and the contents of the cells to leak,” Dr. M-Curtis says. This can cause the plant to turn brown, dry out, and eventually die—but it may not kill the plant down to its roots. Systemic weed killers work a bit differently. According to Dr. M-Curtis, systemic options enter the tissues of the targeted weed and move around until they find “active” parts. There, the weed killer “can act by inhibiting the biological process of cell division, photosynthesis, or amino acid production,” she says. This means that systemic weed killers tend to affect entire plants, killing them down to their roots.
Can you mix different weed killers together?
Every expert we spoke to cautioned against mixing different weed killers. “If you mix weed killers together incorrectly, it can cause phytotoxicity, essentially burning your grass,” Augaitis says. “You may eliminate the weeds but damage your grass and garden while doing so.”
Do weed killers go bad?
Yes, weed killers can go bad. And once they have expired, they may not be as effective as they used to be. Even though weed killers can go bad over time, the “consequences can be minimal,” says Augaitis. If you decide to use an expired weed killer, there’s no way of knowing if it will actually kill your weeds. Augaitis says the product might simply not perform well anymore, which could still leave you with unwanted plants in your yard after treatment.
Take Our Word for It
This article was written by Lindsey Lanquist, a contributing writer for Real Simple with seven years of experience writing lifestyle content. To decide which product to feature in this article, Lindsey spent hours researching the most popular weed killers and preventers and narrowed down the list by considering factors like active ingredients, application style, and targeted plants. She also spoke to three experts—plant scientist Dr. Gladys M-Curtis, lawn care expert Michael Augaitis, and horticulturist Stuart Mackenzie—to learn more about how weed killers work and what to consider before buying one.
