Mixing weed killer concentrate is a cost-effective way to manage unwanted vegetation. Concentrated formulas require careful dilution to achieve the correct strength for application. Precision is necessary; an overly weak mixture is ineffective, while an overly strong one can damage desirable plants and pose environmental risks. Understanding proper dilution and safe handling ensures both the efficacy of the herbicide and the safety of the user and the ecosystem.
Essential Safety Protocols
Handling concentrated chemicals requires strict adherence to personal protective equipment (PPE) guidelines to prevent skin and eye contact. Wear chemical-resistant gloves, such as nitrile or neoprene, which protect against the concentrate’s solvents. Eye protection, such as chemical splash goggles or a face shield, is required to guard against accidental splashes or mists during mixing.
The body must be fully covered using long-sleeved shirts, long pants, and closed-toe shoes, preferably chemical-resistant footwear, to minimize dermal exposure. Mixing must take place in a well-ventilated area, ideally outdoors, to avoid inhaling concentrated fumes or vapors. Choose a location away from children, pets, food preparation areas, and water sources to prevent accidental contamination. Always thoroughly read the manufacturer’s label, as it contains legally binding instructions for safe handling and use.
Understanding Different Chemical Formulations
Weed killer products are categorized as concentrates, which require dilution, or ready-to-use formulas. Concentrated products come in various forms, such as liquids (L), soluble powders (SP), and emulsifiable concentrates (EC). The formulation type influences the mixing sequence, and the correct mixing ratio is determined by chemical properties and the intended target.
Herbicides are also classified by their action on plants: selective or non-selective. Selective herbicides eliminate specific weeds, such as broadleaf varieties, while leaving desirable plants like turfgrass unharmed. Non-selective herbicides destroy almost any green vegetation they contact and are best used for total vegetation control in areas like gravel driveways. The label specifies the required concentration, often expressed as fluid ounces or milliliters per gallon, based on the weed type, growth stage, and the product’s classification.
Step-by-Step Mixing and Dilution
Safely mixing a concentrate begins with accurately calculating the required volume of herbicide based on the product label’s instructions. Labels recommend a dilution rate, such as a percentage solution or ounces per gallon, which must be precisely measured to ensure efficacy. Use dedicated measuring tools that are never used for any other purpose to maintain accuracy and safety.
A fundamental rule is the “water first” principle: fill the sprayer tank approximately halfway with water before adding any concentrate. This procedure prevents excessive foaming, ensures proper chemical dispersion, and minimizes the risk of concentrated splashback. Slowly and carefully pour the measured concentrate into the partially filled tank, using a funnel to prevent spillage.
If the application requires an adjuvant, such as a surfactant or wetting agent, it is typically added next, following the manufacturer’s specific sequence. Surfactants improve coverage and absorption by helping the mixture spread more evenly across the waxy surface of weed leaves. After adding all components, gently agitate the mixture by swirling or shaking the tank, avoiding vigorous motion that creates excessive foam. Finally, fill the tank completely with the remaining water to reach the final volume.
Proper Equipment Cleaning and Storage
After application, the sprayer and all measuring equipment must be thoroughly cleaned to prevent residue buildup and cross-contamination. The recommended method is the triple-rinsing procedure, which removes most leftover pesticide residue. This involves:
- Draining any remaining spray mixture.
- Partially filling the tank with clean water.
- Sealing the tank and shaking it vigorously for at least 30 seconds.
- Draining the rinse water.
This rinsing process is repeated two more times.
The resulting rinse water, known as rinsate, contains a low concentration of herbicide and must never be poured down a drain or into a storm sewer. The safest disposal method is to apply the rinsate onto a previously treated area, using it as part of the application. Store cleaned containers and equipment empty and dry, protected from extreme temperatures. Unused concentrate must be sealed tightly in its original container and stored securely, away from children, pets, and isolated from food or feed items.