Pesticide tank mixing order and jar-test worksheet
Follow the directions for the exact products and formulations to establish herbicide tank mix order. Identify every component before loading. Consult each label and follow the most restrictive requirements when directions differ. Write a loading plan that follows each product’s directions.
Use the general formulation order as a review aid
A general loading sequence is soluble bags and granules, dispersible granules and wettable powders, then water-based suspensions. Next come soluble concentrates, suspoemulsions, oil dispersions, emulsifiable concentrates, adjuvants, soluble fertilizers and drift retardants. Change that sequence wherever a product’s directions require another position for an additive.
Check the adjuvant
An incorrect adjuvant type or rate can cause poor weed control or crop injury. Check the directions of each product rather than adding the farm's usual additive automatically.
Use a jar test for the physical question
Test a small mixture for physical compatibility before loading the tank, using the water you will actually spray with. Separation, clumping, flaking, crystals, gel formation or excessive heat indicate a problem. Follow the test procedure and protective-equipment instructions for the products.
Use the same proportions of pesticides, carrier water and adjuvants in the jar as in the full tank. Let the mixture sit for about 30 minutes, then check it for physical incompatibility. A 28% nitrogen solution mixes with 2,4-D ester but thickens to an unusable mayonnaise-like consistency with 2,4-D amine. If the jar stays clear of problems, apply the mixture to a small test plot to identify non-visible chemical incompatibilities.
Keep adjuvant functions distinct
Ammonium sulfate conditions water, while antifoam and drift-reduction agents modify the spray solution.
Water chemistry can change the question
Glyphosate can bind dissolved metal ions in hard water, reducing performance. Ammonium sulfate counters part of that binding, but enough calcium, iron, manganese, zinc or copper overwhelms it. That is why tank-mixing micronutrient fertilizers with glyphosate for foliar applications is often discouraged.
Adding concentrates separately: the Prowl example
Prowl EC and Prowl H2O should not be mixed together before they go into water. Put each one separately into a spray tank that is already filled with water.
Mixing foliar fertilizers with pesticides: compatibility and label checks
Before mixing, confirm that the exact products are allowed together and compatible on your crop. Check formulation interactions and the function of every adjuvant in the proposed tank. Put the pesticide booklet, the fertilizer directions, the water analysis and your proposed method on the table before you start.
Foliar fertilizer in the herbicide tank
For over-the-top applications of Cornerstone Plus, mixtures with fungicides, micronutrients or foliar fertilizers may reduce weed control or injure the crop. Check the booklet’s crop-specific directions before combining these products.
Far Go herbicide label: check the proposed tank partners
To find the Far Go herbicide label, search by the full product name and the EPA registration number printed on the container with the EPA product lookup guide. Read that label's tank-mix directions before planning a combined application. Take the label, the fertilizer directions and the proposed mixture to your adviser and ask which tank-partner restrictions and loading instructions apply.
Carrier water pH
Water which is too acidic or alkaline can degrade some pesticides or make them less soluble. Choose any water correction for the particular pesticide and target.
Identify the fertilizer formulation rather than its color
Clear fertilizer solutions contain dissolved nutrients. Suspensions contain fine undissolved material maintained in the fluid. Identify which formulation will enter the tank before reviewing agitation and compatibility.
Many fertilizers can be applied directly, such as anhydrous ammonia, urea, urea-ammonium nitrate solutions, triple superphosphate, ammonium phosphates and muriate of potash. Anhydrous ammonia is stored as a compressed liquid, so it needs special handling methods and safety precautions.
Ammonium thiosulfate and herbicides
Ammonium thiosulfate can mix unevenly or be incompatible with herbicides. Before using it as a carrier or an addition, check which products it may be mixed with and how to mix it.
Keep your spray records in one place. Free to start.
If a mixture goes wrong
If a problem occurs, gather the source-water analysis, the complete product list, the loading sequence, the actual quantities, the sprayer calibration record and the field conditions, and keep the original observation (a photo or a jar) alongside the explanation you were given.
Agricultural surfactant selection: NIS, oils, defoamers and mixture checks
An agricultural surfactant is one type of spray adjuvant. It changes how droplets interact with a surface. Surfactants help droplets flatten and spread, while other adjuvants can address foaming, acidity, retention or off-site movement. Identify what the additive needs to do before choosing one. Take the pesticide directions and the exact proposed mixture to the supplier or adviser and ask which additive fits the performance problem you are trying to solve.
Separate a surfactant from the wider adjuvant category
Use the pesticide’s required adjuvant category when selecting an additive. A commercial blend may combine activators, water conditioners and spray-solution modifiers; identify each component’s function.
Four activator types: NIS, COC, MSO and HSOC
Nonionic surfactants (NIS), crop-oil concentrates (COC), methylated seed oils (MSO) and high-surfactant oil concentrates (HSOC) are the activator types; keep them distinct.
Distinguish formulation ingredients from tank additions
An adjuvant can already be present in the formulated pesticide or be added separately before application.
Understand wetting and penetration as separate questions
Surfactants reduce droplet surface tension. Cosolvents help disperse a surfactant in water and hold formulation components together; emulsifiers help oil-based pesticides mix with water. Common NIS products mainly improve spreading; increased spreading does not necessarily increase penetration into the plant. So judge the weed-control result as well as how the wet leaf looks.
Keep water hardness and pH distinct
Water hardness concerns mineral content; pH indicates how acidic or basic water is. Select conditioners for the measured problem and pesticide requirements. Temperature extremes accelerate hydrolysis of susceptible pesticides, changing how long a prepared mixture retains its active ingredient.
Spray-tank defoamer
A spray-tank defoamer reduces foam during mixing. It serves a different function from an activator used to improve herbicide performance.
Mixing order and physical compatibility
Added in the wrong order, products can clump into a paste or gel, separate and clog nozzles, and performance drops. Labels often give the preferred order. Compatibility agents are adjuvants that help incompatible products work together; check the product labels for compatibility before adding them to the mix.
Silicone surfactants and other adjuvant chemicals used in agriculture
Organosilicones are a type of NIS, often called super-spreaders because they decrease surface tension so much. They greatly increase droplet spreading and decrease droplet size, which suits some active ingredients and conditions and not others.
Identify the formulation type first
Identify whether each pesticide is a water-soluble liquid, suspension, emulsifiable concentrate or dry formulation. Distinguish activator additives from utility products for compatibility, foam control and marking before planning the loading sequence.
Liquid fertilizer boom sprayer: review mixture and equipment together
Before loading a liquid fertilizer boom sprayer or farm fertilizer sprayer, settle whether the product is a clear solution or a suspension, as described above. Give your supplier the formulation, how you plan to apply it and any pesticide you want in the same tank, and ask for their compatibility, agitation and cleaning instructions for that setup. Read the pesticide label before it goes into the same tank.
MSO herbicide label: identify the actual mixture component
MSO means methylated seed oil, an activator adjuvant added to the tank; it is not the herbicide itself. Read the herbicide label for whether it calls for an MSO and at what rate. Keep both documents, the herbicide label and the adjuvant's product instructions, at hand during mixing, and do not pick an amount from the abbreviation alone.
Next step
Find each product's label through the EPA product lookup, note any partner restrictions, and write the loading sequence before you fill the tank.