How to Perform a Jar Compatibility Test for Spray Tank Mixtures
Protect your spray equipment and avoid costly tank sludging by testing new combinations of pesticides, liquid nutrients, and APSA-80® adjuvants in a quart glass jar first.
Quick Answer
A jar compatibility test involves mixing small, proportional amounts of your planned spray inputs (water carrier, herbicides, insecticides, fertilizers, and surfactants like APSA-80®) in a 1-quart glass jar. After capping and inverting 10 times, let the jar stand for 15 to 30 minutes. If the solution separates, forms sludge, or gels, the mix is physically incompatible and must not be loaded into your spray rig.
One thing we commonly find is that growers skip the jar test when they're in a rush — and that's exactly when a clogged boom costs the most.
Fifteen minutes with a quart jar can save a full day of downtime and wasted chemical.
Step-by-Step Jar Compatibility Test Procedure
Wear Proper PPE & Use Clean Equipment
Put on chemical-resistant gloves, safety glasses, and long sleeves as specified by pesticide labels. Use a clean, clear 1-quart glass jar with a tight lid.
Fill Jar Half Full with Spray Carrier Water
Fill the jar halfway (approx. 1 pint or 500 mL) with the exact water source used at your farm filling station. Water temperature and hardness affect compatibility.
Add Products in Recommended Sequence (WALES Order)
Add proportional amounts sequentially, mixing gently after each addition:
• W: Wettable Powders (WP) / Dry Flowables (DF)
• A: Agitate thoroughly
• L: Liquid Flowables (F/FL)
• E: Emulsifiable Concentrates (EC)
• S: Surfactants (APSA-80®) and Soluble Liquids (Nutriplant® AG)
Cap, Invert, and Inspect After 15–30 Minutes
Tightly seal lid, invert jar 10 times, and place on a flat surface in a well-ventilated area. Inspect immediately and again after 30 minutes for separation, scum, or curd.
4 Incompatibility Red Flags (Do NOT Load Spray Rig)
Oils or active ingredients separate into distinct layers or float as a thick oily film at the jar surface.
Solid particles precipitate out and form a thick paste or heavy grit at the bottom that cannot be re-dispersed by shaking.
The liquid transforms into a jelly-like consistency that will immediately clog boom suction strainers and nozzle tips.
Chemical reaction generates unexpected heat or violent foam expansion that overflows the jar.
Standard Tank Mix Order (WALES Sequence)
In our experience, following the correct mixing order prevents most compatibility failures before they start. This sequence is the industry standard for agricultural tank mixing.
| Step | Letter | Product Type | Example |
|---|---|---|---|
| 1 | W | Wettable Powders / Dry Flowables | WP, DF |
| 2 | A | Agitate thoroughly | — |
| 3 | L | Liquid Flowables | F, FL |
| 4 | E | Emulsifiable Concentrates | EC |
| 5 | S | Surfactants & Soluble Liquids | APSA-80®, Nutriplant® AG |
Common Mistake: Adding Surfactant First
One thing we commonly find is that growers add the surfactant first because it seems like a "base." This is backwards. Surfactants and soluble liquids go last in the WALES sequence. Adding them early can cause foaming or prevent dry powders from dispersing properly.
Pro Tip: Use Water From Your Actual Fill Station
Based on our real-world experience, the most common cause of unexpected incompatibility is water chemistry. Always fill your test jar with water from the actual farm fill station — not bottled or tap water. Hardness, pH, and temperature differences can change compatibility results dramatically.
Authoritative Tank Mixing Resources
Explore Related Spray Safety Guides
Frequently Asked Questions
What is a jar compatibility test in agricultural spraying?
A jar test is a small-scale trial where small proportional quantities of pesticide products, fertilizers, and adjuvants are mixed in a clean glass jar using farm carrier water. It simulates tank mixing to check for physical incompatibility before loading a large spray rig.
Why should I perform a jar test before adding APSA-80® or Nutriplant® AG?
Water hardness, temperature, carrier pH, and specific formulation chemistry can cause unexpected physical separation, clumping, gel formation, or foam when products are combined. A jar test prevents costly spray tank clogs or wasted chemicals.
What is the standard mixing order for tank mixtures (WALES / DALES)?
The standard mixing sequence is: 1) Water carrier, 2) Wettable powders (WP/DF), 3) Agitate, 4) Liquid flowables (F/FL), 5) Emulsifiable concentrates (EC), and 6) Surfactants/adjuvants like APSA-80® or soluble liquids (SL) like Nutriplant® AG.
What physical signs indicate that a tank mix is incompatible?
Incompatibility signs include separation into oil/water layers, floating curd or scum, heavy precipitation/sludge at the bottom, gel formation, intense heat generation, or uncontrollable foaming.
Have Questions About APSA-80® Tank Mixing?
Contact our technical support team for APSA-80® mixing directions, specimen labels, or compatibility consultation.
