Best weed killer for large areas

7 Best Weed Killer For Large Areas: Clearing Up A Massive Garden

How confident are you in your ability to care for your lawn? While many people are proud of their lawns, seven in ten Americans admit that their lawn can use some improvement. Well-kept greenery is a sight to behold – but proper care can be more difficult than you’d think.

One thing that can turn your greenery from a grassy paradise to a plant-choked patio is weeds. They’re irritating, tenacious, and can cover entire lawns and gardens.

Some weeds are easy to take care of, others are more stubborn. Some types of weed can even grow to cover huge areas of land and can drain the nutrients from your actual plants. In those cases, you need to make use of weed killers.

But your regular herbicide won’t do! When the weeds grow tough and the removal gets nasty, you need a specific type of product. In this article, we’re going to be reviewing the best weed killers for large areas, so strap yourself in, we’re about to banish those weeds to the underworld!

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Quali-Pro Prodiamine 65 WDG weed killer

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Top 7 Weed Killers For Large Areas – Comparison

Name & Brand
Visible result
Active Ingredient
Quali-Pro Prodiamine
24 hours
5 lbs
Check Price
Tenacity Turf Herbicide
2 weeks
Check Price
Roundup Concentrate
12 hours
Glyphosate + Pelargonic
32 oz
Check Price
Roundup Weed
2-4 days
Glyphosate + Pelargonic
Check Price
ROOTX - The Root 
12 hours
4 Pound 
Check Price
Roundup Pro Weed
24 hours
Glyphosate + Pelargonic
2.5 Gal
Check Price
Roundup QuikPro
24 hours
Glyphosate + Pelargonic
6.8 lb
Check Price

The 7 Best Weed Killers For Large Areas

Depending on the weed you’re dealing with, some of these brands will work better than others. Do your research on the growth that you have (and the plants you’re trying to preserve) to find the optimal product that works for you.

Prodiamine 65 WDG 

Prevention is always better than looking for a cure, especially with weeds. If you’re dealing with growths like bluegrass and crabgrass, Prodiamine 65 keeps them at bay and prevents further growth.

Quali-Pro Prodiamine 65 WDG Pre-Emergent Herbicide

Thanks to the high concentration of its active ingredient, this herbicide works well as a pre-emergent weed killer, perfect for lawns and other plantations that require plenty of soil. The formula is highly concentrated, which means you can dilute it to adjust its efficacy depending on where you plant it.

Prodiamine 65 works by being absorbed by the soil and ingested by the microbes that deliver nutrients to every plant, including weeds. Since it’s activated by heat, it targets germinating seed pods just before the conditions turn right for them to grow, dissolving them from within and preventing an early infestation.

The best time to use this weed killer would be twice a year, during the seasons like spring and fall. The strong concentrate stays with the soil for an entire season, allowing to ride out the hotter months of the year without worrying about any weeds that can grow. Since it’s activated by heat, a day with the sun overhead your soil is the ideal condition to use it.

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The product is also low-soluble, meaning that it doesn’t stray too far from the area of application. This is great if your affected areas cross an herb or vegetable garden. The formula works for ornamental patches, tree farms, and other large plantations, so you get the most out of every bottle that you buy!

But while Prodiamine 65 does great with getting rid of pre-emergent broadleaf weeds, it’s less effective when you’re facing full growths. Trying to apply it to already infested areas WILL work, but you risk the formula also affecting the plants you’re trying to save. It won’t kill them, but some users have noticed a difference in plant and soil quality when using the product this way.

Another thing that you should keep in mind is that the granulated form of this weed killer can make mixing it tricky for the uninitiated. The instructions on the bottle are for general use only and may not apply to all types of soil and plants, which means you have to expect to go through a little trial and error before you find the mix that works for you.

Tenacity Turf Herbicide 

Applying herbicides in wetter and more humid conditions can be tricky since formulas need time to be absorbed by the plants and soil. If you have that issue, Tenacity Turf is the choice for you! Activated by water instead of heat, it’s the best weed killer for large areas that see a lot of rain and water exposure.

Syngenta Tenacity Turf Herbicide

It’s a strong formula that can get rid of the most stubborn of weeds like foxtail and nutsedge growths, preventing their growth and stunting them if they’ve already infested an area. It’s designed as a pre and post-emergent herbicide, so it’s a versatile tool to help you fight almost any kind of growth.

Used as pre-emergent formula, Tenacity Turf gets absorbed by moist soil, dissipating its active ingredient in the ground where it targets still-growing seed pods. Once there, it works by cutting off the weed’s supply to the nutrients in the soil, stunting its growth which allows your actual plants to overpower it in the race for nutrients.

If you use it as a post-emergent herbicide on broadleaf weeds, spot spray it on the affected areas and spray them with a little water so the weeds absorb the formula. After being absorbed by the foliage, Tenacity Turf will travel to the roots, killing the weed’s ability to photosynthesize and drying it out from the inside.

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Most gardeners will recommend using Tenacity Turf as a pre-emergent weed killer since it’s one of the few herbicides that can be used on re-seeded or newly sodded soil. Any existing weeds will blanket the newer growths and help fuel your actual plants, giving them more nutrients to break down and use when they sprout!

Because of how it’s activated, Tenacity Turf requires a surfactant to work. Using a surfactant like Dawn or Ajax into the herbicide mix prevents the formula from beading on the weeds when applied and sliding off instead of being absorbed. That’s also the reason we would recommend it for a pre-emergent application – it’s just easier to use it on damp soil.

While it can be more expensive than other brands, Tenacity Turf is a great weed killer to use if your area has many weeds that you need to treat. The versatility of this product gives you a lot more value for one purchase than buying multiple kinds of weed killers at a time!

RoundUp Concentrate Max Control 365 Vegetation Killer 

When dealing with unwanted plant growth in areas like patios, driveways, or garden paths, RoundUp Max Control is your best option. Not only does it remove weeds fast, but it also works as a great pre-emergent herbicide, keeping these areas clear of any growth for up to a year!

Roundup Concentrate Max Control 365 Vegetation Killer

The weeds absorb the active ingredient via the leaves, and it’s soluble enough to get into the hairline cracks and gaps in the hardscape. After application, it travels all the way to the root of the weeds and dries them out for easier removal. It’s a powerful concentrate that can target almost any growth and kill it within hours!

With the large sizes, RoundUp offers a lot of value for homeowners that place a lot of emphasis on the aesthetics of their property. Since the spray formulation makes it easier to apply, it’s ideal for large areas that need regular treatment – while also being effective enough to be used sporadically.

Follow the directions as instructed and mix with water. It’s rainproof within 30 minutes of application, so you can apply it whenever you need to. You can spot spray on areas with dense growths for targeted applications, or you can use a spray to disperse it over large areas.

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RoundUp Max Control 365 is a non-discriminating herbicide, which means it will kill ALL vegetation on contact. You should be careful when spraying it on areas near plant growth you’re trying to keep safe since it won’t be washed off by water or anything else once applied.

Results can also vary with time and efficacy. Most people who used RoundUp say that the product has different levels of effectiveness depending on the weed and area applied, so keep this in mind when you’re starting to mix your formula. There’s some confusion to how fast it works, with some users saying it worked within days and others reporting weeks.

Some users also report that using the RoundUp garden sprayer as a bad option – the dispenser doesn’t cover a wide area and can be uneven with application. It’s much better to buy the bottle itself and provide your own means of application for the best results.

If you need an inexpensive and effective way to keep your hardscape areas clear, then RoundUp Max Control 365 is a good choice. It’ll clear your area of any growth and prevent them from growing back, and repeat applications can help you get rid of any other greenery.

RoundUp Weed and Grass Killer Super Concentrate 

One of the strongest RoundUp formulas, the Weed and Grass Killer can clear any area of any vegetation, including prepared soil and mulched areas. It targets widespread growths like nutsedge and kills them to the root, preventing further spread and growth after application.

Roundup Weed and Grass Killer Super Concentrate

RoundUp is highly soluble, so it can get into any nook and crevice of the application area without difficulty. It’s rainproof after 30 minutes of application, and you can see visible results within days. Best used as a spot spray around flower gardens and other hardscape, it’s a cost-effective solution when you want to blanket an area in herbicide.

The formula is very concentrated, so you need to be careful when mixing. Over spraying an area can make it leak to adjacent plots that you’re trying to preserve, which can affect the soil and plants there. Like most RoundUp products, this herbicide doesn’t discriminate: it WILL kill any vegetation it comes into contact with.

However, it’s best used with newly-renovated lawns or areas since it can function as a pre-emergent herbicide if there are no other growths in the way. Apply it and wait for the formula to take hold, though we will warn you that affected soil may lower in quality even after a single application.

It’s also not suited for anything else aside from spot spraying since the formula is toxic to both people and animals. While it becomes inert a few hours after application, it’s best to not use these on areas that see a lot of foot traffic without clearing it out first. Always wear protection during the mixing and application process, since the formula can cause irritation upon skin contact.

You can stretch out a bottle of RoundUp diluting it with water, but we recommend that you stick to the 22-gallon limit. Diluting the formula any more can lessen its effectiveness, which can end up costing you more time and money in the long run. Most gardeners will suggest that you stick to the formula on the bottle, but if you have more experience, adjust based on the areas you’ll be spraying.

Only spray using either a handheld sprayer or a wand. Using irrigation systems like sprinklers can spread the formula farther than you intended, putting your other plants at risk. Careful application is key to getting the best results out of this herbicide, so treat it with caution!

ROOTX – The Root Intrusion Solution

Piping systems are some of the most difficult areas to weed out. If you have growths in your pipes from root systems in your garden or lawn, ROOTX is the best choice to flush them out. You can kill growths from within and prevent further incursions for the next season, keeping your pipes unblocked and root-free.

ROOTX - The Root Intrusion Solution

Best applied for pipe systems under turf or old trees, ROOTX is the perfect, non-intrusive solution for dealing with root growths. Since it expands into foam once it’s reached the piping system, it can fill up every crevice to target the smallest of weeds and seal them off after application. And while it’s effective at removing vegetation in the pipes, it’s gentle enough to not hurt the plant itself.

ROOTX works by dissolving the roots at their point of entry into the pipe, then sealing the growth so it doesn’t continue to expand outward. This allows it to flush a piping system without leaking out into the soil or the surrounding area, which lowers the chance that you’ll contaminate other plants.

It’s also easy to disperse: mix the powder with water and pump it through the system. You can expect results within a couple of days, though you may need to check the end of the piping system for larger roots that have gotten dislodged instead of dissolved.

You should apply ROOTX with caution, as the foam can get very thick quickly. Always pour it as you’re pumping the system with water and never all at once. The ingredients are concentrated, so you’ll only need a couple of spoons of formula to flush your pipes, though you can add more if you have a large system.

Always use protection when applying ROOTX since its ingredients are toxic. The fine dust can blow into your nostrils or eyes if you aren’t being careful, so keep it far away from your face. You should also take care if you’re using this on the pipes of a water feature, since it can blow away the foam or seep into the surrounding area, killing any plant life it comes in contact with.

Only use ROOTX for piping systems. The foam is difficult to control if you use it above ground, and the formula can dilute the soil’s pH levels if absorbed. And while it can take care of most roots, it’s less effective for large growths that have penetrated multiple sections of piping, even with repeat application.

Roundup Pro Weed Killer Concentrate 

For large, industrial-scale areas that need complete plant removal, RoundUp’s Pro Weed Killer Concentrate is the best option. It’s a nuclear formula that you can use to scour every nook and cranny of vegetation for months, with repeat applications keeping growths away for good.

Roundup Pro Weed Killer Concentrate

At 2.5 gallons of concentrate, this isn’t a product that’s suited for most gardens. The bigger size also means more concentrate – while other RoundUp products can deliver faster results per application, the formula used with the Pro Weed Killer Concentrate can ensure complete coverage of a sprayed area.

This is one product where reading the instructions is crucial. Since you can’t use everything out of the bottle at one, you need to mix or dilute this weed killer to get the best results. Spot spray application is fine, but be careful to not over-spray since it can cause staining on hardscape surfaces when applied too much.

Pro Weed Killer Concentrate is best used for large areas since it works fast and dries, which prevents it from being washed away by the wind and rain. While it takes a while to work compared to other RoundUp products (most users report having to wait for a couple of days up to two weeks), once weeds have absorbed it, the job is as good as done.

One thing to keep in mind when using this formula is the expiry date. Since it comes in larger size compared to other products, it can become less effective with time, especially after being opened. We also don’t advise that you use this on smaller lawns since the concentrate is so strong that it can leak through other areas and affect the soil quality.

Proper application of Pro Weed Killer Concentrate is also important since the product is toxic. Even trace amounts can cause mild to moderate symptoms upon skin contact, and the formula is hazardous to people and animals until it’s been absorbed into the ground and rendered inert. When spraying, be careful to not hit any other plant growth that you don’t want to get rid of!

Most users recommend applying this product on prepared soil or pre-landscaped lawns since the formula is soluble enough to seep through the soil and get rid of any germinating seed pods. However, the best results still come for it a post-emergent broadleaf remover since it can move through foliage quicker than the ground.

RoundUp QuikPro 

Trusted by landscape contractors and real estate agents, RoundUp QuikPro is the best weed killer for large areas that work fast and without sacrificing things like soil quality! As one of the most powerful post-emergent herbicides, this product can remove growing and grown weeds in days.

Roundup QuikPro

It targets most broadleaf weeds and other grasses through their foliage, being absorbed after application and making its way to the roots. It stops the plant’s ability to absorb nutrients from the soil, which burns the plant from the inside, causing it to wilt and die. While it’s a nondiscriminatory herbicide, it does a good job of keeping tougher turfs alive.

However, the main benefit of using QuikPro is its ability to not taint the ground. This makes it an ideal pick for removing existing lawns without harming soil quality, which can be essential for areas that need renovations or have been taken over by weeds. Spray the solution over the area, watch the plant life die, then reseed as you like!

Unlike other weed killers, it flows through sprayers without clogging. You can use it for irrigation spraying or even tank sprays with no worry about damaging the tube or the machine, and you’ll still get the same results with half the effort. It only needs a couple of applications to remove all weeds from an area, and you can dilute the solution so it lasts longer.

If you want to burn out a lawn, most users would recommend cutting or mowing the grass before application. QuikPro is potent, but it has a short burn time, which means you’ll need several repeat applications if you’re using it on tall grass. While you can stretch out the solution while mixing, it’ll be less effective if you use it this way.

One thing to note is that QuikPro is NOT a pre or post-emergent herbicide. It will target and kill growing or grown weeds, but the formula isn’t strong enough to prevent future growth. This means that while you can get rid of present weeds or foliage on your lawn, you’ll need repeat applications to keep it that way.

But if you want an easy to measure weed killer to remove the growth from your lawn, it’s difficult to find anything better than RoundUp QuikPro. It’s more affordable than other brands and can keep your areas growth-free without affecting the soil!

Tips On Choosing The Perfect Weed Killer For Large Areas

Weed killers aren’t a one-all solution. While general-purpose brands exist, it’s much better for you to choose a specific product that can target your needs. Here are our tips for finding the right match:

  • Pre vs Post Emergent Herbicides

Weeds can vary in how resilient and widespread they can be and choosing the right herbicide can help in mitigating some of their stubbornness. Post-emergent herbicides are great for keeping your areas clear of growth after the weeds are gone, while pre-emergent brands prevent growth from the beginning.

  • Application Area

Some weeds thrive on grassy areas while others can snake into hardscape foundations. While you can control your application somewhat with the right tools and practice, limit your weed killer to an area where it’ll do the least amount of damage. Most of the brands we’ve given don’t discriminate between plants, so you need to make sure your application area is well-cordoned off.

  • Weather And Environment

Herbicides have different activation methods: some might need to be absorbed by the ground before working while others are activated via heat. Keeping the weather (or the season) in mind when applying weed killers helps you spray them so that none of it gets washed off before it takes effect.

  • Surrounding Foot Traffic

Most weed killers have high quantities of their active ingredients, which can pose a health hazard to small children and animals in the vicinity. While none of the effects are lethal, prolonged exposure can bring several health hazards to people in the area. Always make sure that everyone – including you – is protected when applying herbicides.

  • Purpose Of The Area

Is the affected area ornamental? Or maybe sees a lot of foot traffic? Understanding your goals for removing weeds is crucial to picking the right product, since it will affect everything from application to how often you use it. Use heavy-duty weed killers for larger areas, or spot-spray gentler formulas for long, winding paths.

Cleared And Clean

While removing weed from large areas might seem like a big challenge, choosing the right weed killer can make this task a breeze. With a little patience and some effort, any owner can manage unwanted growth without resorting to expensive services to fix and maintain their property.

The best weed killer for large areas can not only save you money, but it also saves you time and effort that you can spend on other things! Careful use and application can give you a lot more confidence in your lawn and make you the proud owner of a pest-free garden.

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