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Roundup Weed Killer

weed image by Sandra Henderson from

What to Do If I Get Roundup in My Eye?

Roundup is a herbicide produced by Monsanto. If it contacts the eyes, Monsanto says that after contacting a doctor or poison control, the eyelids should be held open and the eye gently rinsed for 15 to 20 minutes. Contact lenses should be taken out after five minutes of rinsing.

Roundup is a herbicide produced by Monsanto. If it contacts the eyes, Monsanto says that after contacting a doctor or poison control, the eyelids should be held open and the eye gently rinsed for 15 to 20 minutes. Contact lenses should be taken out after five minutes of rinsing.

How to Make Roundup Stick to Weeds

Pour Roundup in the bucket. Saturate the sponge completely with the Roundup herbicide spray. Take care not to drip Roundup onto any desired plants as you saturate the sponge.

Rub the saturated sponge over the foliage of the weeds, covering the weed growth completely with the herbicide. Even a small amount of herbicide on the plant foliage is probably enough to kill weeds. Apply the Roundup to every weed using the same method.

Wait three days to assess the condition of the weeds. If they do not seem like they are visibly dying, reapply the Roundup using the same method.


Choose a warm and calm day when the sun is shining brightly. Temperatures above 60 degrees F are ideal.

Apply Roundup at the beginning of the growing season, in the middle of the growing season and again at the end of the growing season to kill all weeds growing in your landscaping areas.


Wear eye protection and gloves when you work with Roundup to prevent the chemical from contacting your skin. Long pants and long sleeves will protect your arms and legs.

Keep people and pets away from the wet Roundup while it dries.

Types of Roundup

Weed and Grass Killer

Roundup’s “Weed and Grass Killer” kills any vegetation that it touches and is available in three concentrates (as of 2010). The ready-to-use bottle is just like it sounds—ready to use. It is already mixed with water and comes with its own sprayer attached to the container. Refills are available for purchase also. The “Concentrate Plus” and “Super Concentrate” must be mixed with water in an herbicide sprayer, according to the manufacturer's directions; they yield up to 10 gallons of spray and 23 gallons of spray respectively.

Extended Control Plus Weed Preventer

The “Roundup Extended Control Weed and Grass Killer Plus Weed Preventer” will kill existing grass and weeds and prevent new growth for four months after application. It is available in a ready-to-use bottle and as a concentrate that, when diluted, provides up to 5 gallons of spray.

Poison Ivy Tough Brush Killer

Roundup’s “Poison Ivy Plus Tough Brush Killer” herbicide kills poison ivy, poison oak, kudzu, wild blackberry and other woody brushes. It also comes in a ready-to-use bottle and as a concentrate, which mixes to produce up to 5 gallons of spray. Even after you kill poison ivy or oak, keep in mind that your skin and lungs can still become irritated if breathed in or touched.

Does Roundup Contaminate Soil for Gardening?

Glysophate and Surfactants

Glyphosate is a broad spectrum herbicide and a main active ingredient in Roundup. A surfactant is a chemical that helps glyphosate to penetrate tough plant cells. Both chemicals are toxic to humans and animals. Together, their toxicity increases exponentially.


According to Robert Kremer, a microbiologist with the U.S. Department of Agriculture's Agricultural Research Service, glyphosate changes soil composition and disrupts the normal balance of microorganisms in the soil, leading to an increase in fungal growth and harmful bacteria.


Plants such as legumes fix nitrogen from the atmosphere into the soil by relying on the beneficial bacteria rhizobia. The glyphosate in Roundup inhibits rhizobia, preventing the natural and necessary addition of nitrogen to the soil.


The U.S. Environmental Protection Agency has called the glyphosate in Roundup “extremely persistent” because of its lengthy half life (the time it takes for half of the amount of glyphosate applied to break down). In studies from around the world, glyphosate has been present in the soil up to three years after the initial application.

How to Mix Roundup

Get a tablespoon, cup or quart measuring device depending on how much you want to mix and the strength that you want. The stronger the mix the more potent the roundup is. Use a tank for large spray jobs or a spray bottle to mix small amounts. Do not use steel if it is not lined. The only exception is stainless steel.

Add about half of the water needed for your mix.

Add the roundup portion. For a 1-gallon mix add any where from 1 tbsp. to 18 tbsp. for a strength of 0.4 percent to 7 percent. For 25 gallons add from 1 1/2 cups up to 7 quarts of Roundup for the same range of strengths. And for 100 gallons add 1.6 quarts to 7 gallons.

Add the rest of the water.

Stir the mixture to make sure that the product is spread throughout the container.

How to Use Round Up Weed & Grass Killer

Apply Roundup when the weeds and grasses are actively growing. The best application time is during warm and sunny weather, above 60 degrees F. Spraying Roundup on cloudy days that are as cool as 50 degrees F. also can produce effective results.

Spray the weed and grass killer when the air is calm. Protect adjacent plants with a piece of cardboard to block natural drift from the spray.

Adjust the nozzle to the preferred spray setting: foam or spray.

Spray the grasses or weeds until they are soaking wet or covered with foam.

Wait at least 10 minutes after Roundup has been applied before watering the surrounding plants. Roundup Weed & Grass Killer Ready-To-Use Plus product label offers rainproof protection that states rain or watering 10 minutes after application will not wash away effectiveness.

Plant ornamental trees, flowers and shrubs at least 24 hours after applying the weed and grass killer to an area of the garden.


Store the product in the original container with the nozzle turned to the closed position. Keep it out of direct sunlight and do not allow it to freeze.


Wear gloves when applying any pesticide. Avoid contact with eyes and clothing. Allow people and pets to enter the application area only after the spray has dried.

How to Mix Roundup Concentrate

Wear gloves and eye protection when mixing Roundup to prevent the herbicide from spraying onto your hands or in your eyes. Keep children and pets away from the mixing area while you work.

Fill the spray bottle approximately three-quarters full with cool water. Add 6 oz. of regular Roundup concentrate or 2.5 oz. of Roundup super concentrate.

Close the spraying container tightly and shake gently to mix the ingredients completely.

Open the spraying container again and fill it to the top with water. Close the container again tightly and shake to mix the ingredients well.


Apply Roundup to weeds when the temperature is at least 60 degrees F, sunny and windless for best results.

Follow package recommendations and instructions carefully.

How to Kill Velvetleaf With Roundup

Mow velvetleaf or cut it down with clippers before it flowers, usually in late summer. Pull up as much as you can.

Wait to apply the Roundup on a calm day and when rain is not expected.

Put on rubber gloves, goggles, long sleeve shirt, socks, shoes and long pants.

Spray the cut velvetleaf with a Roundup product, such as Roundup Ultra, that is suitable for the site where your velvetleaf is growing. Read the label and following application rates for the size of your area and type of Roundup you are applying. Spray with even sweeping motions over the top of the plants.

Repeat mowing and spraying if you notice new velvetleaf growing.

Does Roundup Work on Pachysandra?

The herbicide Roundup works on pachysandra. Roundup is a postemergent, systemic herbicide that contains glyphosate. It is non-selective and will kill most any annual or perennial that it touches. Roundup is sprayed onto foliage, then moves into the root system, killing the plant.

Directions for Roundup Spray

Choose a day that is sunny, dry, calm and above 60 degrees F for best application results.

Wear long pants, long sleeves and gardening gloves as you apply the Roundup to protect your skin from the chemicals.

Cover surrounding plants with the plastic tarp to protect them from the Roundup spray, if desired.

Adjust the nozzle of the spray so it either foams onto the plants or sprays onto the plants. If you need to control the application of the Roundup and protect surrounding plants, choose the foam setting. If this is not a concern, choose the spray setting.

Apply the Roundup to the desired area, directing the product so it completely saturates all of the foliage of the undesired plant, as well as the base of the plant.

Reapply the Roundup to the plants if the plants are not completely dead after two weeks.


For best results, apply Roundup to plants when they are growing actively. This will disperse the glyphosate through the plant system faster. If you accidentally spray Roundup onto desired plants, immediately spray these plants with a garden hose to rinse off the Roundup.


Keep children and pets away from the spray area until the Roundup spray dries completely. If you get Roundup in your eyes, rinse your eyes with plain water for 20 minutes. Call a physician. Rinse skin immediately if Roundup contacts your skin. If anyone ingests Roundup, call Poison Control immediately.

How to Use Roundup to Kill Grass

Avoid watering the grass for 24 hours before applying the Roundup to ensure a dry environment that will allow the Roundup to penetrate the grass at full strength. Wait for a dry day when there's little to no chance of rain.

Pour the Roundup Ready-to-Use product into a garden sprayer, if needed; some bottles of Roundup include a built-in spray applicator.

Mist the Roundup product onto the grass, applying an even mist onto all exposed grass surfaces. Start at one end of the lawn and walk away from the direction of the spray to ensure that you don't walk on the freshly sprayed herbicide.

Wait for the Roundup to kill the grass. Brown and wilting grass will begin appear within six hours of applying the Roundup Ready-to-Use product, according to Monsanto, manufacturer of Roundup.


Roundup Ready-to-Use is not the only version of Roundup. Monsanto also recommends Roundup Weed & Grass Killer Concentrate Plus and Roundup Weed & Grass Killer Super Concentrate. Both take longer to kill grass--the former 12 hours and the latter four days--and require mixing the chemical with water. Follow the product's label for mixing guidelines. If you are replanting new grass or vegetation in the area, wait for four to seven days to give the herbicide time to dissipate. Roundup Ready-to-Use doesn't require mixing with water.


Wear protective gloves and safety goggles when handling any herbicide product.

All glyphosate-based herbicides such as Roundup will kill grass. Common alternatives--including 2,4-Dichlorophenoxyacetic acid, also known as 2,4-D--may not be effective against many grass species.

How to Mix Roundup Weed Killer

Measure out 5 tbsp. of Roundup Weed and Grass Killer for every 300 square feet of space you intend to cover. For example, if you need to kill 1,500 square feet of lawn, you would need 25 tbsp. of Roundup.

Measure out 1 gallon of water for every 300 square feet of space you need to cover. For example, if you need to cover 1,500 square feet of space, you would need 5 gallons of water.

Add your Roundup and water to a garden sprayer. Give the garden sprayer a shake to mix the two ingredients together.

Spray the weeds you want to kill until they are completely wet with the Roundup. Do this on a day when the outdoor temperature is above 60 degrees F.


This product is waterproof after 30 minutes.

If you encounter any emergencies when using this product call 1-800-246-7219.


Read the entire product label to ensure that you use this product properly. For example, it is recommended that you wear gloves and goggles when working with Roundup.

This product is poisonous to pets and humans.

How to Dilute Roundup

Inspect the hand-held sprayer for dirt or debris. Rinse out the sprayer if necessary.

Fill hand-held sprayer with 1 gallon of clean water.

Pour recommended amount of Roundup solution into the hand-held sprayer. A 0.5 percent solution requires the addition of 0.7 oz of Roundup solution, while a one percent solution requires the addition of 1.3 oz of Roundup solution. Add the Roundup to the sprayer when pouring the last few ounces of water into the sprayer, to begin the mixing process.

Add a defoaming agent, if desired, to the water and Roundup solution. This will lessen the foaming action that occurs during both mixing and spraying the solution.

Mix the water and Roundup, slowly, by hand. Do not use mechanical mixers, which will only encourage foaming.


Thoroughly wash all components of the hand-held sprayer when you are finished with the Roundup application.


Never apply Roundup through an irrigation system.

Always use clean water when diluting Roundup. Dirty water can reduce the effectiveness of Roundup.

Does Roundup Kill Junipers?

Utah Juniper image by Carol Hyman from

If Roundup, a post-emergent systemic herbicide, comes in contact with junipers, it can kill them. The Roundup label warns users to keep the herbicide away from foliage, green stems and exposed non-woody roots of any desirable plants or trees.

How Much Roundup Will Kill Conventional Corn?

Corn image by DSL from

Roundup herbicide is a systemic weed and grass killer. When sprayed upon any unwanted growth, including corn, the plant moves the chemical to the roots, causing the plant to die. The green growth on corn must be sprayed so most of it receives the chemical. One application is sufficient.

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