How to Use Roundup to Kill Plants


Monsanto developed its popular Roundup Original herbicide product as a systemic glyphosate-based herbicide. Once sprayed onto plants, the plant absorbs the chemical through its foliage and stems. Annuals will begin to die within four days. Perennials will start turning yellow and dye within a week, according to Monsanto. Spray Roundup on your landscape to control weeds and other unwanted plants.

Step 1

Wait for a dry, sunny day when no rain is in the forecast for 24 to 48 hours.

Step 2

Fill a plastic hand-held sprayer with 1 gallon of water. Add 2 or 2.7 oz. of Roundup Original, using the larger amount only if a recent application of Roundup didn't kill all the plants.

Step 3

Close the hand-held sprayer. Shake it to thoroughly mix the contents.

Step 4

Stand with your back to the wind and face the targeted plant.

Step 5

Spray the solution onto all exposed surfaces of the plant. Apply enough to evenly moisten the entire plant, but not so much as to cause dripping or puddling.

Tips and Warnings

  • Roundup is extremely toxic. Monsanto recommends wearing closed-toe shoes with socks, protective eyewear and chemical-resistant gloves while applying the chemical.

Things You'll Need

  • Hand-held herbicide sprayer
  • Roundup Original
  • Measuring cup or tablespoon


  • "Handbook of Sustainable Weed Management"; Harinder Singh, et al.; 2006
  • Monsanto: Roundup Original Product Label

Who Can Help

  • Monsanto
Keywords: apply Roundup herbicide, kill plants, spray Roundup herbicide

About this Author

Josh Duvauchelle is an editor and journalist with more than 10 years' experience. His work has appeared in various magazines, including "Honolulu Magazine," which has more paid subscribers than any other magazine in Hawaii. He graduated with honors from Trinity Western University, holding a Bachelor of Arts in professional communications, and earned a certificate in applied leadership and public affairs from the Laurentian Leadership Centre.