If your lawn is getting out of control with weeds, hand pulling them just isn’t going to cut it. Sure, you can tug out a few by the root, but it may be difficult and time-consuming to do that for your entire yard. That’s where weed killers come in, often the best method for lawn weed control.
There are tons of lawn weed killers on the market, so it may be difficult to choose the exact right one for your lawn. The This Old House Reviews Team has rounded up the top weed killers for 2021—and how to choose them. For extensive weed control and lawn care, we recommend considering a lawn company like TruGreen. If you’d like a free quote from the company, call 866-817-2287 or fill out this simple form.
Before you can choose the proper weed killer, you’ll have to determine exactly what type of weed you’re dealing with. Different weed types require different treatments—what’s effective for one may do little or no damage to another.
There are three main categories of weeds: broadleaf, grassy, and grass-like.
1. Broadleaf weeds
These weeds have broad, flat leaves, so it’s unlikely you’ll mistake them for grass. They thrive in soil that’s lacking key nutrients, and they come in different types—annual, biennial, and perennial, so different broadleaf weed varieties require different chemicals depending on their life cycle.
Examples of broadleaf weeks include dandelions, ground ivy, clover, chickweed, dollarweed, thistle, and oxalis.
2. Grassy weeds
Grassy weeds have leaves that look like grass blades, and they grow one at a time. Examples of grassy weeks include crabgrass, quackgrass, goosegrass, and foxtail.
3. Grass-like weeds
This weed type resembles grass, but its leaves are more tube-like and triangular than flat. Examples of grass-like weeks include garlic, nutsedge, and wild onion.
How Weed Killers Work
Weed killers work by using chemicals that kill the weed or prevent their growth. There are a variety of different herbicide types to treat weeds at different stages of their life cycle—or before they even sprout. Here are the main characteristics to consider when choosing your specific weed killer.
Pre- or post-emergent
Pre-emergent weed killers target weed seedlings before they get a chance to sprout. If weeds have already popped up, this type won’t help. Post-emergent weed killers are designed to eradicate weeds in their active growing season. You apply post-emergent weed killers directly to the plants’ leaves.
Selective or non-selective
This aspect is critical. Selective weed killers eliminate weeds without harming beneficial plants nearby, while non-selective herbicides will damage all nearby plants, even if they’re beneficial.
Systemic or topical
Systemic weed killers attack the entire plant, including the roots. Topical herbicides, on the other hand, only kill the areas that the weed killer is applied to.
Persistent or non-persistent
Persistent weed killers stay active after you apply them to prevent future weeds. Non-persistent weed killers don’t offer ongoing weed control.
How to Apply Weed Killer
Even if you select the right weed killer, applying it incorrectly can make your efforts fruitless, and the wrong application can cause complications.
Many weed killers need to be diluted with water and put in a spray bottle. The product’s label will explain precisely how much water and weed killer you’ll need to combine. Some weed killers, however, come in granular form. Solid weed killers must be applied with a spreader.
When applying weed killer, timing is everything. You don’t want to apply weed killer immediately after mowing your lawn since that could harm your tender grass. The same goes for fertilizer. In both cases, wait several days before applying weed killer.
The weather also plays a role in when to apply weed killer. Applying weed killer when it’s too hot can stress your grass, and applying it right too soon before it rains means it can wash away before it gets absorbed.
The 5 Best Weed Killers
Here are the top five best weed killers for 2021.
#1: Southern Ag 2, 4D Amine Weed Killer
This inexpensive, selective broadleaf weed control and grass killer is a classic. It uses the chemical 2, 4-D, which is highly effective against weeds. It’s a simple, straightforward weed killer composed of strong ingredients and doesn’t feature much filler. It avoids common grass strains like St. Augustine grass.
#2: Roundup Weed & Grass Killer Concentrate Plus
Roundup has long been a trusted name in getting rid of weeds. This concentrate plus variety is heavy duty and claims to work fast—killing off weeds in as little as two to four days. It doesn’t harm beneficial plants in nearby areas, and it’s rain-proof 30 minutes after application.
This powerful, fast-acting weed killer battles the exterior part of the weeds it contacts as well as the root systems. It kills stubborn weeds very efficiently, and spraying weeds selectively will ensure your lawn stays intact.
#4: Preen Garden Weed Preventer
This pre-emergent, selective weed killer offers residual effects, with ingredients remaining active in the soil for three months after application. Preen prevents nearly 30 broadleaf weed varieties without hurting nearby plants.
#5: Scotts Turf Builder Weed & Feed
Scotts’ most powerful weed and feed thickens grass while crowding out weeds. It’s especially effective against dandelions and clover. The company offers a satisfaction guarantee, promising your money back if you aren’t satisfied with your results.
Top Recommended Professional Lawn Care Company: TruGreen
The This Old House Reviews Team’s top selection for lawn care, TruGreen, offers both pre- and post-emergent weed control to restore your lawn to its former health and make sure it can compete against future weeds. The lawn care company offers five annual plans with varying levels of coverage in every state except for Alaska. If you’d like a free quote, call 866-817-2287 or fill out this simple form.
How to Prevent Weeds
When it comes to tackling weeds, the best defense is a good offense. You should always take these steps to keep your grass hardy and robust, reducing the chances of weeds taking over.
- Water deeply and infrequently—If you want your grass to have strong, deep roots, you need to water deeply and infrequently instead of choosing shallow, daily watering. With deep, sturdy roots, your grass can grow nice and thick and compete with weeds that may try to grow.
- Mow high—Weeds need sunlight to grow. If you let your grass blades grow taller by setting your lawn mower to the first or second highest setting, the grass will grow tall enough to cast shade on any weed seeds, preventing them from sprouting.
- Feed regularly—Stressed lawns are more susceptible to being crowded by weeds. Feeding regularly will keep your lawn lush and make it less hospitable to enterprising weeds.
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