Glyphosate is a widely used, non-selective herbicide used to control grasses and broadleaf weeds. This active ingredient is sold as a concentrated liquid that must be mixed with water before it can be effectively applied. Correct dilution is essential because it ensures the product is effective, economical, and safe to handle. Since commercial products vary significantly in their percentage of active glyphosate, the specific amount needed per gallon of water depends entirely on the concentration purchased.
Standard Mixing Ratios for Common Concentrations
The most common commercial product is a 41% glyphosate concentrate, which serves as a benchmark for general weed control. For an average application targeting common weeds, the recommended rate for a 41% concentrate is typically between 1.5 to 2.7 ounces per gallon of water. This generally creates a 1% to 2% solution, which is effective for actively growing annual grasses and weeds.
For a slightly stronger 53.8% concentration product, the general application rate is often lower, ranging from 1.5 to 3 ounces per gallon of water. This higher percentage concentrate requires less liquid volume to achieve a similar herbicidal strength. A standard rule of thumb for general-purpose weed control with a 41% concentrate is to use about 2 ounces of the product per gallon of water.
For example, one common label recommendation for general weed control using a 41% concentrate is 1.5 ounces (three tablespoons) per gallon. These guidelines are designed for maximum efficacy on average weeds while still following economical application rates.
Adjusting Dilution Based on Weed Type and Desired Effect
The standard mixing ratios are a starting point, and the final dilution should be adjusted based on the specific type of vegetation being treated. Annual weeds, which complete their life cycle in one season, generally require the lowest concentration mixture for effective control. These lighter mixtures are often successful when the weeds are small and actively growing, typically less than four inches tall.
Tougher, established perennial weeds, brush, or woody plants require a stronger concentration to ensure the herbicide translocates properly. For these difficult targets, the concentration of a 41% product may be increased to 4 to 5 ounces per gallon of water, or even up to 6.5 ounces per gallon for a 5% solution.
If the concentrate percentage is different from the common 41%, the mixing math must be adjusted to deliver an equivalent amount of the active ingredient. For instance, to create a 2% solution with a lower-concentration product, a proportionally greater volume of that concentrate would be needed compared to a 41% product. Always refer to the product label for specific percentages, which may be expressed as a percentage solution or ounces per gallon.
Essential Safety Precautions and Mixing Procedures
Handling concentrated glyphosate requires strict adherence to safety protocols. Personal Protective Equipment (PPE) is mandatory when mixing and applying the concentrate.
Personal Protective Equipment (PPE)
At a minimum, PPE includes:
- Chemical-resistant gloves
- Protective eyewear
- Long-sleeved shirts
- Long pants
- Closed-toe shoes with socks
The proper mixing procedure begins with ensuring the spray equipment is clean and uncontaminated. Start by filling the spray tank approximately halfway with clean water. The measured amount of glyphosate concentrate is then added to the water, followed by the remaining water.
This order helps prevent excessive foaming and ensures the herbicide is properly dispersed within the tank. The solution should be agitated gently to mix the components thoroughly, but vigorous shaking should be avoided to limit foam formation. Never mix glyphosate in galvanized steel or unlined steel containers, as this can cause a chemical reaction that produces highly combustible hydrogen gas.
After application, any unused, diluted solution should be applied to an approved treatment area, as storing mixed solution for long periods is generally not recommended. Equipment must be thoroughly rinsed with clean water immediately after use to prevent corrosion and cross-contamination. The concentrated product should be stored in its original container, tightly closed, and away from food or children.