Roundup Mixing Instructions

Updated February 21, 2017

Roundup is a brand name for a glyphosate herbicide produced by Monsanto Corp. It kills weeds without harming grass or other vegetation, making it popular with farmers and homeowners alike. Roundup is manufactured in both ready-to-use bottles and large, concentrated bottles that can be diluted after purchase. The concentrate produces more ounces of finished spray than premixed bottles, making it more popular and cost-effective.

Determine what strength of Roundup is necessary to kill the weeds on your property. Delicate plants such as lantana can be killed with a weaker solution, while hardier plants like beachgrass require a strong concentration of herbicide for best results. Check the Roundup product label for a complete listing of appropriate concentrations.

Put on protective equipment before mixing Roundup. Heavy work gloves and goggles should be worn to prevent chemical burns, and a breathing mask is necessary to keep from inhaling minute chemical particles.

Fill a 1-gallon sprayer with clean, warm water. Use the measuring spoons to pour the specified amount of Roundup into the sprayer. For example, killing honeysuckle requires a 0.8 per cent concentration of Roundup. It takes 28.4gr., or 2 tbsp, of Roundup mixed with a gallon of water to produce a 0.8 per cent solution.

Place the lid on the sprayer and shake gently back and forth to combine. Spray weeds early in the morning, so the product has a chance to penetrate to the root of the plant during the heat of the day. Spray the weeds again in a week if they still show signs of life.


Avoid spraying Roundup near animal troughs or feed pans. It can be toxic if ingested.


Don’t spray weeds on days with rain in the forecast. Roundup does have a one-hour rain warranty, but heavy storms will dilute the chemicals and render them ineffective.

Things You'll Need

  • Gloves
  • Breathing mask
  • Goggles
  • 1-gallon garden sprayer
  • Water
  • Roundup concentrate
  • Measuring spoons
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About the Author

Louise Lawson has been a published author and editor for more than 10 years. Lawson specializes in pet and food-related articles, utilizing her 15 years as a sous chef and as a dog breeder, handler and trainer to produce pieces for online and print publications.