Top 4 Best Pre Emergent Weed Killers (**2021 Review**)

There are two ways to get rid of weeds: before they sprout and after they sprout.

If you wait until summer to start killing weed, you’ll have to endure weeks or months of slowly dying weeds making your lawn look ragged and patchy.

If you do it in late winter or early spring before the seeds germinate, sprout, and emerge from the soil, you won’t have to put up with any of that.

Best Pre-Emergent Weed Killers
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Preen Extended Control Weed Preventer
Stop weeds before they start with Preen Extended Control Weed Preventer.
FEATURES
  • Long-lasting, prevents weeds up to 6 months
  • Easy flip-top applicator
  • Use around a wide range of perennial plants

It takes some work and planning (well, maybe more than “some”), but the end result will be a yard you can brag about without having to worry about pulling weeds all the time.

In this review, you can expect to learn:

  • What are pre-emergent weed killers?
  • How do pre-emergent weed killers work?
  • Are pre-emergent weed killers effective?
  • How do you use a pre-emergent weed killer?
  • And our overall #1 pick for best pre-emergent weed killer!

If you're short on time, you can click here to jump straight to our top choice for best pre-emergent weed killer.

ImageProduct
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Preen Extended Control Weed Preventer
  • Long-lasting, prevents weeds up to 6 months
  • Easy flip-top applicator
  • Use around a wide range of perennial plants
  • Long-lasting, prevents weeds up to 6 months
  • Easy flip-top applicator
  • Use around a wide range of perennial plants
View on Amazon
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Green Light Amaze Grass and Weed Preventer
  • The active ingredients are Oryzalin & Benefin
  • Ready to use
  • Four-month residual impact
  • The active ingredients are Oryzalin & Benefin
  • Ready to use
  • Four-month residual impact
View on Amazon
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Bonide DuraTurf Crabgrass and Weed Preventer
  • The active ingredient is Dithiopyr
  • Convenient shaker
  • Long-term control
  • The active ingredient is Dithiopyr
  • Convenient shaker
  • Long-term control
View on Amazon
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Hi-Yield Crabgrass And Weed Killer
  • The active ingredient is Dithiopyr
  • 4,000 square feet per bag
  • Good price point
  • The active ingredient is Dithiopyr
  • 4,000 square feet per bag
  • Good price point
View on Amazon

Our Overall #1 Rated Pick

Updated as of May 9th, 2021

  • Long-lasting, prevents weeds up to 6 months
  • Easy flip-top applicator
  • Use around a wide range of perennial plants

Stop weeds before they start with Preen Extended Control Weed Preventer. When used as directed, it can prevent weeds for up to six months. And it can be used safely on groundcovers, flowerbeds, and around shrubs and trees labeled for use. 

It comes with a convenient flip-top applicator. So, there is no equipment needed to use the product. It also can cover up to 805 sq ft with one application. 

Preen Extended Control Weed preventer is environmentally safe. Its granules stay on the ground so there is no worry over pesticide drift like with sprays. 

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Terminix-logo

Rating: 97.50

Our #1 Ranked For: Termites,Bed Bugs, and Larger Infestations

aptive-logo

Rating: 97.00

Our #1 Ranked For: Ants, Roaches, Spiders, and Rodents Issues

Orkin-Logo

Rating: 95.70

Our #1 Ranked For: Mosquito Removal, Fleas, Ticks, Wasps, And Other Stinging Insects

Top 4 Best Pre-Emergent Weed Killers

What Are Pre-Emergent Weed Killers?

A pre-emergent herbicide is a weed killer that has to be sprayed or spread long enough before weeds begin sprouting that the herbicide has time to soak into the ground down to the depth of the seeds. It’s preemptive weed control, killing them before they sprout.

By contrast, post-emergent means after a plant has emerged from the soil, so a post-emergent herbicide is a weed killer that can only be used on broadleaf weeds, grassy weeds, and others after they emerge from the soil and produce their leaves.

For more information on what pre-emergent weed killers are, and when to use them, check out the video below!

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How Do Pre-Emergent Weed Killers Work?

Pre emergent weed killers do not kill weeds before they begin germinating. Instead, they interfere with their growth to prevent them from completing the germinating process.

Pre-emergent herbicides can be classified as a growth regulator. If the weed can’t finish growing, it dies.

Are Pre-Emergent Weed Killers Effective?

Yes, if you follow the directions on the label. Herbicide labels contain important safety information for use, storage, and disposal. For your safety and the safety of those around you, you need to read that information and follow it exactly.

The first line on every label reads, “It is a violation of federal law to use this product in a manner inconsistent with its labeling.” This has given rise to the saying, the label is the law, which is literally the truth.

Pre-Emergent Weed Killer Facts

How To Use A Pre-Emergent Weed Killer

Pre-emergent herbicides can be liquids that require a low-pressure sprayer for their application, or granules that need to a hand spreader for broadcasting them across the lawn. Your lawn care herbicide application also requires the use of a soil temperature thermometer.

You need a soil thermometer because timing is critical when you’re using a pre-emergent herbicide. The soil has to be at the correct temperature before you apply the herbicide. The ideal soil temperature range is 50-55 degrees.

When your soil reaches that point will depend on what latitude you’re at. The further north you are, the later in the year it will be. At the extreme southern tip of Texas, it could as early as January 1. Above the 45th Parallel, it could be anytime after May 30.

Take daily soil temperature readings until the temperature is within that range for 2-3 days in a row. Once that happens, it’s time to begin your application.

  • Liquid Herbicides

Mix the herbicide with water according to the directions on the label. A 3-4 gallon backpack sprayer will be sufficient for treating most yards. You should only have to refill it a few times to treat the whole yard.

Begin spraying at the foundation of your house in a gradually increasing spiral around the house until you’ve covered the entire yard. Each band of the spray should overlap the previous band by several inches to ensure complete coverage.

Once you’ve finished the application, follow any directions on the label for agitating or tilling the soil. If you don’t or can’t till the soil, a second application may be necessary. See the label for details.

  • Granule Herbicides

Granules are easy to spread. Follow the directions on the label to set the spreader release the appropriate amount of granules. You should turn the handle about twice per second while moving at a normal walking pace, around 3mph.

Use the same gradually increasing spiral pattern as for a liquid herbicide. Once you’re finished, follow the directions on the label for how much to water your yard. Granules are almost always water activated so this is a necessary step.

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Are Pre-Emergent Weed Killers Safe Around My Pets And Children?

No. Herbicides, pre-emergent or post-emergent, are toxic chemicals designed to kill plants. While people and plants are different, we still share many commonalities and herbicides can cause chemical injuries to people if precautions aren’t taken.

Warning

Pets and children should be kept out of treatment areas during the application process and for 24 hours afterward unless the instructions on the label list a different length of time.

Best Pre-Emergent Weed Killers Reviewed

  • Long-lasting, prevents weeds up to 6 months
  • Easy flip-top applicator
  • Use around a wide range of perennial plants

Stop weeds before they start with Preen Extended Control Weed Preventer. When used as directed, it can prevent weeds for up to six months. And it can be used safely on groundcovers, flowerbeds, and around shrubs and trees labeled for use. 

It comes with a convenient flip-top applicator. So, there is no equipment needed to use the product. It also can cover up to 805 sq ft with one application. 

Preen Extended Control Weed preventer is environmentally safe. Its granules stay on the ground so there is no worry over pesticide drift like with sprays. 

Pros

  • Long-lasting, prevents weeds up to 6 months
  • Easy flip-top applicator
  • Use around a wide range of perennial plants
  • Covers a wide area with one application

Cons

  • Not for use around vegetables or edible plants
  • Requires watering right after application
  • This product cannot be used around several types of perennials, so it is best to read the label carefully
  • The active ingredients are Oryzalin & Benefin
  • Ready to use
  • Four-month residual impact

This pre-emergent herbicide comes in a 10-pound bag of granules. One application will prevent weeds for up to four months. It controls annual bluegrass, chickweed, crabgrass, foxtail, goosegrass, henbit, prostate knotweed, and purslane, among others.

It can safely be used on established turfgrass such as bahiagrass, bermudagrass, centipedegrass, St. Augustinegrass, and zoysiagrass, up to 4,000 square feet per bag.

It is also safe to use on established flowers, roses, shrubs, and trees. See the label for a complete list.

Pros

  • 4,000 square feet per bag
  • Easy to use
  • No mixing required

Cons

  • Can be expensive for large yards
  • The active ingredient is Dithiopyr
  • Convenient shaker
  • Long-term control

This pre-emergent herbicide comes in a 4-pound jug of granules. It prevents germination to give you long-term crabgrass control. It’s ready to use in a shaker so you don’t need a spreader.

It also kills annual bluegrass, barnyard grass, chickweed, crabgrass, dallisgrass, foxtail, goosegrass, henbit, knotweed, purslane, speedwell, and spurge. It’s safe to use on bahiagrass, bermudagrass, centipedegrass, St. Augustinegrass, and zoysiagrass.

The small package lends itself to use on small yards and spot treatments rather than large yards or fields.

Pros

  • Ready to use
  • Works on a wide range of weeds

Cons

  • Only for small yards or spot treatments
  • A bit expensive for the size
  • The active ingredient is Dithiopyr
  • 4,000 square feet per bag
  • Good price point

This is a pre-emergent herbicide in a 12-pound bag of granules. The active ingredient is listed as Dimension, another name for Dithiopyr. This is a consumer-use product only, not intended for commercial use. One bag covers about 4,000 square feet.

It kills annual bluegrass, barnyard grass, chickweed, crabgrass, dallisgrass, foxtail, goosegrass, henbit, knotweed, purslane, speedwell, and spurge. It’s safe to use on bahiagrass, bermudagrass, centipedegrass, St. Augustinegrass, and zoysiagrass.

Pros

  • Easy to use
  • Kills a wide range of weeds
  • Inexpensive

Cons

  • May clump during periods of high humidity

Stop weeds before they start with Preen Extended Control Weed Preventer. When used as directed, it can prevent weeds for up to six months. And it can be used safely on groundcovers, flowerbeds, and around shrubs and trees labeled for use. 

  • Long-lasting, prevents weeds up to 6 months
  • Easy flip-top applicator
  • Use around a wide range of perennial plants
  • Covers a wide area with one application

Want To Solve Your Pest Problem Now?


We’ve partnered with Terminix to bring you exclusive discounts and priority service for your pest control needs. Click to get your free instant price quote.

Limited Time: Save $50 off your pest control service.

Final Thoughts On Pre-Emergent Weed Killers

Pre-emergent herbicides are the best choice for long-term weed prevention. They create a preventative barrier that stops weeds before they get started. Using them requires a bit more elbow grease than with post-emergent herbicides but the results are worth the extra work.

Make sure the weeds in your yard are listed, then buy with confidence, knowing you can keep them off your lawn.

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Rating: 97.50

Our #1 Ranked For: Termites,Bed Bugs, and Larger Infestations

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Rating: 97.00

Our #1 Ranked For: Ants, Roaches, Spiders, and Rodents Issues

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Rating: 95.70

Our #1 Ranked For: Mosquito Removal, Fleas, Ticks, Wasps, And Other Stinging Insects