How Much Roundup To Add Per Gallon of Water? (Find Out Now!)

Ryan Womeldorf
by Ryan Womeldorf
Roundup is commonly used for killing weeds and other unwanted vegetation. But the mixture needs to be diluted with water in order for customers to get the most bang for their buck. What is the right amount of mixture? Well, after lots of tests, we think we found the answer.

Roundup is a herbicide meant to help kill weeds and any other invasive plant that is causing trouble in your garden. Made by the Scotts Company, it can be quite effective at cleaning up unwanted growth in your garden and yard.

If you are using Concentrate plus, you will be using 6 ounces of RoundUp per gallon of water. For the Super Concentrate formula, you will need about 2.5 ounces of RoundUp per gallon of water. Always check the label for any RoundUp product you purchase for instructions on how to use it properly.

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Why Do I Need to Use a Specific Amount of Roundup?

When weeds poke their ugly selves into your garden or around your yard, it becomes imperative to get rid of them as soon as possible. You could always pull them out (make sure that you get the roots, too) but that is time-consuming and labor-intensive.

Roundup makes things easier, but it takes care and preparation. Otherwise, too much Roundup could wind up doing damage to plants that you want to keep healthy. With the proper measurements, you can keep those plants safe while ridding yourself of those pesky weeds and other things that grow invasively in your garden or yard.

How Much Roundup per Gallon of Water for Weed and Grass

Roundup is generally used for weed and grass control since it is a herbicide. A herbicide works to kill specific types of plants, though there are others that can work for more comprehensive use (more later).

Weed & Grass Killer Concentrate Plus. When using Roundup Weed & Grass Killer Concentrate Plus, you will need to mix anywhere from 3-6 ounces (6-12 tablespoons) of the concentrate with per one gallon of water. How many gallons you need will depend on the size of the space that you are working on.

Weed & Grass Killer Super Concentrate. When using Roundup Weed & Grass Killer Super Concentrate, you will need to mix anywhere from 1.5-2.5 ounces (3-5 tablespoons) for every gallon of water. As is the case with the Concentrate Plus, how much you need depends on the size of the space that you are working in.

How Much Roundup to Use with Other Roundup Herbicides per Gallon of Water

Roundup makes a wide range of herbicides for different situations and scenarios. While weed and grass growth is the most common problem facing landowners, it is far from the only thing that they have to contend with.

Here are a few other Roundup formulas and how much you want to use per every gallon of water used.

Grass, Weed, and Pre-Emergent Herbicide. If you are using Roundup as both a weed and grass killer but looking for an herbicide that treats pre-emergent grass and weeds, there is a formula to use. Mix roughly 6 ounces (12 tablespoons) for every gallon of water that you use. You can spray both the soil and the existing weeds until they are thoroughly wet.

Woody Stump Herbicide. You may have a fresh stump in your yard after a shrub or tree has been cut down. You can use Roundup to help get rid of it by using a general weed and grass killer or the brush killer in specific. All you need to do is drill a few holes in the stump and then pour the concentrate in its undiluted form into each of the holes.

Vine and Brush Herbicide. You may have invasive vines or even dense brush hanging around your yard. Not only can be it unsightly to look at, it can stifle the growth of other plants in your yard. Mix 6 ounces (12 tablespoons) of the Roundup Poison Ivy Plus Tough Brush Killer into every gallon of water that you use.

How Much Roundup Do You Need for 20 Gallons of Water?

A gallon of water mixed with Roundup should be enough to handle most smaller yards. But what to do when you have a much larger space? How much Roundup will you need if you are using 20 gallons of water or so?

If you are using Roundup Super Concentrate and plan to mix it with roughly 20 gallons of water, the label suggests about 2.5 ounces per gallon of water. So, if you are planning on using 20 gallons of water, then you would need 50 ounces of Roundup Super Concentrate to get the job done.

Can I Mix Roundup and 24D?

Roundup isn’t the only herbicide out there. For instance, there is a mixture of Glyphosate and 24D (known as 24D for short) that is considered to be the standard herbicide mixture when it comes to fallow weed control for dryland areas.

Some growers feel that the activity would be the same if they mixed the 24D with Roundup, a popular retail herbicide. Growers did not realize, however, that the salt formulation created would make a major difference in growth control.

Is 24D the Same as Roundup?

Roundup is easily the most popular brand of herbicide in the United States, having been on the market since 1976. While it is great for standard residential use, farmers have been looking for an alternative to farming herbicides.

24D. 2,4-dichlorophenoxyacetic acid, also known as 2,4-D (or 24D) might not have the catchy name that Roundup does, but it is proving to be particularly effective. It shares many of the same qualities – both good and bad – in Roundup. It is primarily made for commercial/farming use but would likely work fine for residential use.

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What Natural Weed Killer Remedies are There?

While Roundup is a great way to get rid of invasive growth like weeds and grass, it does have its caveats. Some people do not feel comfortable using the chemicals within and prefer to look for alternatives to kill the growth in their yards.

Thankfully, there are quite a few ways to kill weeds naturally. Here are just a few that you can employ if you don’t feel comfortable with the chemicals within store-bought herbicides.

1. Cardboard/Paper/Newspapers

If you don’t feel comfortable using herbicides, you can simply smother the grass or weeds. It will take a little bit of time, but with some scrap cardboard, paper, and newspaper, you can simply kill the weeds by depriving them of sunlight and nutrients.

The darker the material, the better you will do. Don’t use color pages because the ink could potentially seep into the soil and poison the plants. Lay down several layers so that the grass or weeds can’t simply breakthrough. Repeat the process as much as you need to until the growth has dissipated and died off.

2. Concentrated Vinegar

Before we get into it, if you are using something to kill weeds or grass, make sure that you only apply it to the weeds and grass. You never know which plants may be susceptible to the various methods on this list.

That said, vinegar has acetic acid. That acid is a drying agent when it comes into direct contact with the leaves of plants. If you spray vinegar on younger plants, it tends to be more effective at killing them because the roots have not matured and are still quite weak. Make sure that your other plants and vegetables are covered securely. Even a little bit of vinegar splash could cause them to dry out and weaken if not die entirely.

3. Liquid Detergent Soap

There is a good chance that you have discovered the versatility of liquid detergent soap. It can be used as a cleaner for a variety of things around your home, but it can also make for an excellent aid in the removal of weeds and for general gardening.

The liquid detergent soap works by compromising the surfaces of waxy and hairy weeds in particular. That allows the aforementioned acetic acid to adhere to the leaves better, doing a more effective job of killing the weeds. All you need to do is mix a couple of drops of the soap in with your vinegar spray and you will have a highly effective weed killer.

4. Corn Gluten Meal

Corn gluten meal is a by-product of corn syrup and corn starch. Not only that, but it is also quite competent when it comes to controlling weeds. It works by stifling the germination process, so this can only be used before the weeds actually begin to germinate.

All you have to do is spread it around your plants and any seedlings that have taken root. This will prevent the weeds from using up the nutrients that your plants need, killing them before they ever get started.

5. Boiling Water

This method is the most cost-effective, and you can do it quickly and easily without a trip to the store. That said, it also is one of the methods that requires the most control. The collateral damage it can cause can be substantial.

Pouring boiling water directly onto the weeds should instantly kill the leaves and the roots. This method is particularly effective for paved surfaces. The water can get down into the spaces and cracks easily and quickly.

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Ryan Womeldorf
Ryan Womeldorf

Ryan Womeldorf has more than a decade of experience writing. He loves to blog about construction, plumbing, and other home topics. Ryan also loves hockey and a lifelong Buffalo sports fan.

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