Buying guide for best pre-emergent herbicide
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If you’re into gardening or even just a homeowner who wants to keep their lawn looking clean, eventually you’re going to have to deal with weeds. Undesirable plants, otherwise known as weeds, compete with the plants you do want in your yard for nutrients, light and water. In short, you don’t want them anywhere near your lawn.
Eliminating weeds once they've sprouted can be challenging, though, especially if you have a large area to treat. So for that reason, it’s best to take a proactive approach and use a pre-emergent herbicide to stop them dead in their tracks before they germinate. They don’t kill existing weeds, but they’re an excellent preventative measure that ensures you don’t have to deal with them for at least several months.
Our top choice is the The Andersons Barricade Professional-Grade Granular Pre-Emergent Weed Control, which is a reliable season-long option for preventing weeds before they start.
Editors’ picks
The Andersons Barricade Professional-Grade Granular Pre-Emergent Weed Control
Editors’ Favorite
Form: Granules | Active Ingredient: 0.48% Prodiamine | Item Weight: 40 lb | Square Footage Covered: 12,880 | Weeds Prevented: Crabgrass, Goosegrass, Foxtail, Poa Annua, Lambsquarter, Henbit
The Andersons Barricade Professional-Grade Granular Pre-Emergent Weed Control is highly effective in preventing the emergence of various weeds, including crabgrass, annual bluegrass and goosegrass. It’s made with patented DG technology, ensuring granules dissolve as soon as you add water, helping it absorb into the soil.
The small particles deliver more coverage per square inch and superior performance, and a single 40-pound bag can cover up to 12,880 square feet. Its active ingredient is 0.48% Prodiamine, which effectively prevents weed germination.
One of the best pre-emergent herbicides, The Andersons Barricade Professional-Grade Granular Pre-Emergent Weed Control is a customer favorite for its ability to stop crabgrass from taking hold and its broad coverage, making it suitable for treating larger areas.
Scotts Halts Crabgrass & Grassy Weed Preventer Pre-Emergent Lawn Weed Killer
Great Value
Form: Granule | Active Ingredient: Pendimethalin 1.71% | Item Weight: 9.63 lb | Square Footage Covered: 5,000 | Weeds Prevented: Crabgrass, Foxtail, Barnyardgrass, Fall panicum, Goosegrass, Oxalis, Prostrate spurge, Poa annua, Henbit, Chickweed, Corn speedwell
The Scotts Halts Crabgrass & Grassy Weed Preventer Pre-Emergent Lawn Weed Killer is one of the cheapest yet reliable ways to prevent weeds from growing, particularly crabgrass, goosegrass, foxtail and some broadleaf varieties.
With Pendimethalin 1.71% as the primary active ingredient, this herbicide is excellent for fall application to prevent winter weed emergence. One bag can cover up to 5,000 square feet, and the herbicide won’t be affected by the elements when properly applied.
This herbicide forms a barrier quickly after application and can last four to eight weeks. It’s safe for pets, and you can get year-round coverage with two applications. It’s affordable, effective and works on a variety of pesky weeds.
Quali-Pro Prodiamine 65 WDG Pre-Emergent Herbicide
Best Pro-Grade Liquid
Form: Granule | Active Ingredient: 65% prodiamine | Item Weight: 5 lb | Square Footage Covered: 1,000 | Weeds Prevented: Crabgrass, Foxtail, Goosegrass, Poa Annua, Chickweed, Henbit, Knotweed, Spurge, Japanese stiltgrass
A pro-grade liquid, the Quali-Pro Prodiamine 65 WDG Pre-emergent is highly effective at taking out weeds, such as crabgrass, foxtail, goosegrass and annual bluegrass, before they even start to emerge, keeping your lawn clean and clear for months.
This 5-pound bag can last up to five years for a 1,000-square-foot lawn. Per 1,000 square feet, all that’s required is 0.185 to 0.55 ounces, depending on control level and the type of weeds you want to prevent.
This herbicide is especially effective against broadleaf weeds, and many prefer its liquid form for easier application compared to granular herbicides. Because you only require a small amount per 1,000 square feet, it’s an excellent bargain pick even though the upfront cost is higher than that of other herbicides.
Atticus Torocity Herbicide
Best for Overseeding & New Lawns
Form: Liquid | Active Ingredient: 40% mesotrione | Item Weight: 8 oz. | Square Footage Covered: 96,000 | Weeds Prevented: Crabgrass, Barnyard grass, Nimblewill, Poa Annua, Yellow nutsedge, Clover, Ground ivy, Dandelion, Thistle, Oxalis, Verbena, Creeping Charlie
If you’re planning to overseed your existing lawn or establish a brand-new lawn, the Atticus Torocity Herbicide is one of the top choices for preventing weeds, such as crabgrass, barnyard grass, annual bluegrass, verbena and dandelion.
Flexible application times make this herbicide one of the best for those who missed the mark on stopping pre-emergent weeds. It works well for prevention, but it’s also effective at killing weeds that have already grown. It comes with a pre-marked syringe so you don’t have to guess how much to use for your lawn, and a single teaspoon creates enough solution to cover up to 2,000 square feet.
Whether you’re overseeding or starting a new lawn, this herbicide is a must-have for preventing weeds from developing early. Unlike other herbicides, this one works as a post-treatment as well, so you can keep it handy whenever you spot weeds taking over your lawn.
Preen Extended Control Weed Preventer
Best for Flower Beds & Landscaping
Form: Granule | Active Ingredient: Trifluralin & Isoxaben | Item Weight: 10 lbs | Square Footage Covered: 2,245 | Weeds Prevented: Crabgrass, Chickweed, Clover, Dandelion, Thistle, Oxalis, Garlic mustard, Japanese stiltgrass
Offering extended weed control, the Preen Extended Control Weed Preventer is one of the best options for homeowners who need weed prevention in specific areas, such as in flower beds and around shrubs, trees and ornamental plantings, instead of on lawns.
Its active ingredients effectively target grassy weeds such as crabgrass, foxtail and annual bluegrass and also stop the emergence of broadleaf weeds such as chickweed, spurge and oxalis. You’ll get up to six months of protection with a single application, and you can cover up to 2,245 square feet with one 13.75-pound bag.
Although it’s not suitable for lawns or vegetable gardens, you won’t want to use anything else for targeting specific areas. It's a versatile herbicide that’s ideal for homeowners looking to keep trees, flower beds and shrub areas in pristine condition.
Preen Lawn Crabgrass Control
Best for Late Starters
Form: Granules | Active Ingredient: Dithiopyr 0.19% | Item Weight: 15 lb | Square Footage Covered: 5,000 | Weeds Prevented: Crabgrass, Barnyardgrass, Yellow foxtail, Carpetweed, Henbit, Knotweed, Spurge, Chickweed
Preen Lawn Crabgrass Control is a granular herbicide that’s excellent at stopping crabgrass and other weeds before they establish. It creates a barrier in the soil that targets germinating seeds, helping keep your lawn clean and weed-free.
It provides up to four months of weed prevention and controls newly sprouted weeds for several weeks. This added post-emergent effect makes it more forgiving than typical preventers, which are stricter about timing and may require multiple applications for full prevention. Fifteen pounds covers up to 5,000 square feet and works well on various weeds, including crabgrass, barnyardgrass and yellow foxtail.
This herbicide is perfect for late starters who missed the early spring window, as it delivers excellent control even if applied later than standard pre-emergent herbicides. Plus, it’s one of the more affordable herbicides at just $22 for a 15-pound bag,
When is the best time to apply pre-emergent herbicides?
Once weeds have sprouted, a pre-emergent herbicide won’t do you any good. Their sole purpose is to prevent weeds from germinating. Once germination occurs, the weed will grow, and you’ll have to find other means to get rid of it.
Many homeowners and caretakers apply pre-emergent herbicides just once a year in the spring, but for year-round protection, at least twice a year is recommended, with an additional application in the fall. However, it’s important to note that timing is primarily based on soil temperature.
For example, some weeds begin germinating when soil temperatures reach about 55 degrees for several consecutive days. In warmer regions, soil warms earlier and stays warm longer, so applications may happen earlier in the year and sometimes multiple times. In cooler climates, there’s a narrower application window because warm temperatures are less frequent.
Here are some of the most common types of weeds and the best time of year to prevent them:
- Crabgrass: A fast-spreading summer annual grassy weed. Attack it in early spring before the soil hits 55 degrees.
- Chickweed: A low-growing cool-season broadleaf weed. Apply pre-emergent in the fall before it germinates in cooler weather.
- Annual bluegrass (poa annua): A clumping winter annual grass with seed heads. Prevent it with a fall application before the soil drops below 70 degrees.
- Dandelions: A deep-rooted perennial broadleaf weed that’s best controlled with fall prevention plus post-emergent treatment for existing plants.
- Spurge: A heat-loving, mat-forming broadleaf weed. Apply pre-emergent in early spring before the soil warms.
- Goosegrass: A tough summer annual grass that germinates later than crabgrass. Use a slightly later or split spring application for control.
Key considerations
Activation
Pre-emergent herbicides don’t work by themselves because they need water to dig into the top layer of the soil. All you need is 0.25 to 0.5 inches of water after application to activate it and form a barrier that prevents weed germination. Light irrigation for 20 to 30 minutes is usually enough to do the trick, but a steady rainfall of under 0.25 inches works as well.
You only need to water the herbicide once, but be mindful that too much water can disrupt the barrier and reduce its efficacy. For best results, you’ll want to water it after application or the same day if possible. If you wait too long, it may break down due to sun exposure and lose its effectiveness.
Liquid vs. granular
Liquid: A liquid herbicide is easier to apply with a pump sprayer and lets you cover ground more evenly. It’s also easier to target specific areas and usually absorbs faster into the soil.
Granular: It’s the best solution for large lawns, and you can also mix it with fertilizer to kill two birds with one stone. However, it can sit unevenly if not spread widely, and it can take longer to activate than liquid herbicides.
Selective vs. nonselective
Selective: Selective herbicides are your best option for preserving your lawn and the plants you actually care about. They target specific areas without harming anything else. The only trouble with selective herbicides is that you need to ensure the one you use is effective in killing the weeds plaguing your lawn or garden.
Nonselective: Nonselective herbicides wipe out everything they touch, including plants you might not want to get rid of. That makes them unsuitable for specific areas, but covering a lot of ground, they can be especially effective and more practical. If you want a full reset or clear an entire area, they’re definitely the way to go. However, more caution is required when using nonselective herbicides, as they can damage your lawn if sprayed accidentally.
Ingredients
Not all herbicides are made the same. Many brands use different active ingredients in herbicides that target specific weeds. Although many preemergent herbicides target common weeds, you’ll need to look for a specific active ingredient in some cases.
Pendimethalin: A common active ingredient that controls many grasses and some broadleaf weeds. Best used for crabgrass, goosegrass and foxtail.
Prodiamine: A long-lasting pre-emergent known to last longer than pendimethalin. It’s especially effective on crabgrass, annual bluegrass, chickweed and other common weeds.
Isoxaben: Often used in ornamental beds and mixed landscapes, it’s your best bet for tackling broadleaf weeds such as chickweed, spurge, oxalis and clover.
Trifluralin: This is best applied in landscaping and garden beds and is effective at preventing annual grasses and some broadleaf weeds.
Oryzalin: Excelling at controlling many annual grasses and some broadleaf weeds. It's also effective on crabgrass, goosegrass and pigweed.
Dithiopyr: A versatile ingredient that’s effective at stopping post-emergent activity on young crabgrass. It can also help with other annual grasses and select broadleaf weeds.
How we analyzed
We analyzed the active ingredients of various herbicides to determine which are most effective at eliminating different weed types. We chose both granular and liquid herbicides as our top picks to give readers more variety in managing pre-emergent weeds. Additionally, we considered price and the amount of herbicide required to treat a specific area.
FAQ
Q. How much does pre-emergent herbicide cost?
A.Pre-emergent herbicides can range from $20 to $80. However, the size of the bag of granules or bottle of liquid herbicide is a significant factor affecting cost.
Q. When can my children and pets safely use the lawn after applying a pre-emergent herbicide?
A. After you water the pre-emergent herbicide and it dries completely, a process that takes about 24 to 48 hours, the lawn is generally safe to use again. However, some experts suggest holding off a full 72 hours before letting your children and pets play on the grass, especially if your pets are prone to nibbling on it.
Q. Can you apply too much pre-emergent herbicide?
A. Yes, applying too much pre-emergent herbicide can have adverse effects on your lawn without improving control. All herbicides have label directions that specify the amount required for effectiveness based on a predetermined area.
