How to Mix Weed Killer

Controlling weeds is one of the most difficult challenges homeowners, gardeners and farmers face. Weeds steal nutrients and water from cultivated plants, making them weak and vulnerable to problems.
Hand removal and hoeing are options for lawns or gardens with few weeds. But larger areas or more severe infestations may require the use of weed killers.

Things You'll Need

• Protective gear, including goggles, face mask, gloves and protective clothing
• Herbicide
• Spray container (hand-held, backpack or tank style)
• Water
• Measuring cup with markings for ounces and / or milliliters
• All-terrain vehicle (ATV) or tractor (optional)

Instructions

Lawn Weeds

1. Identify the types of weeds you need to eradicate. The University of Illinois offers an online tool to help you identify different weeds and includes photos and descriptions of 172 species of weed (reference 2).

2. Determine whether you want to use a contact herbicide or a systemic herbicide.

   According to The University of Rhode Island's Factsheet on How Herbicides Work (reference 3), a contact herbicide kills only the part of the plant that the herbicide touches (i.e., leaves, flowers and stems).

   Systemic herbicides are absorbed by the plant and move through the plant to tissue that is remote from the point of application. Systemic herbicides are particularly effective against established perennial weeds.

3. Put on protective gear -- including goggles, face mask, gloves and protective clothing -- to prepare for mixing and applying herbicides.

4. Mix your chosen weed killer concentrate according to package directions. Most herbicides require mixing a designated number of ounces of weed killer with a set amount of water. For example, Trimec Ready Spray Lawn Weed Killer should be mixed at a rate of one fluid ounce to one half gallon of water for spot treatment of weeds.

5. Use a hand-held or backpack sprayer for spot application. Thoroughly wet the weeds with the herbicide, but avoid spraying cultivated plants.

6. Dispose of any excess herbicide as instructed on the manufacturer's label.

Field and Pasture Weeds

1. Identify the types of weeds you need to eradicate. Fields and pastures will probably have more than one type of weed that needs to be killed and you may need to use more than one herbicide.

2. Identify the type of herbicide or herbicides you need to use. The University of Florida Extension's Electronic Data Information Source offers advice on herbicides for particular weeds in pastures and rangeland and which herbicides can be mixed. See the link to their website in the Resources section below.

3. Contact your local U.S. Department of Agriculture Extension office to determine if your state requires that you be licensed to use the type of herbicide required to control your weeds. If a license is required, the extension office can provide contact information for your to register for approved courses. A list of extension offices is available at www.csrees.usda.gov/Extension/.

4. Put on protective gear -- including goggles, face mask, gloves and protective clothing -- to prepare for mixing and applying herbicides.

5. Fill an appropriate-sized spray tank halfway with water, then add the amount of herbicide needed and continue filling the tank to the level indicated by the herbicide manufacturer's label.

6. Follow the herbicide manufacturer's label to determine if an additive such as crop oil should be included to enhance the herbicide's performance and add the amount indicated to the tank. Gently agitate the tank to ensure adequate mixing.

7. Use a hand-held or backpack sprayer to spot treat weeds and woody brush, or treat larger areas of weeds using a boom sprayer attached to your ATV or tractor.

8. Dispose of any excess herbicide as instructed on the manufacturer's label.

Tips & Warnings

• In addition to using herbicides where indicated, DuPont recommends mowing, mulching, crop rotation and managing crop planting times to give crops a competitive growing advantage over weeds.

• Once you have used measuring cups and other measuring tools to prepare your herbicide, do not reuse those same items for food preparation purposes.

References

• The Royal Horticultural Society's Pests and Diseases; Pippa Greenwood and Andrew Halstead; 2003.
• University of Illinois Online Weed Identifier Tool
• University of Rhode Island's Factsheet: How Herbicides Work

Resources

• Trimec Ready Spray Lawn Weed Killer Application Rates
• University of Florida Extension's Electronic Data Information Source
• DuPont's FAQs about Herbicide Resistant Crops and Weed Management