Tank Mixing Order: The Jar Test and Why Sequence Matters
By Eric, TurfDial Founder · Reviewed September 1, 2026
Load three products into a 25-gallon tank in the wrong order and you can end up with a sprayer full of clumps, a separated layer floating on top, or a mix that's lost most of its effectiveness before it ever reaches the nozzle. The fix costs you the whole load — time, product, and the application window you were trying to hit. A five-minute jar test before you fill the tank catches the problem for the price of a mason jar and some patience.
The Tank Mix Calculator sizes exactly how much of each product goes into your tank once you know the mix works. This guide covers the part that comes before the math: getting the products into the tank in an order that actually stays mixed.
Why Mixing Order Matters
A spray tank isn't a bucket where you dump everything in and stir. Different formulations behave differently as they hit water. Wettable powders need to wet out and disperse before anything else changes the water chemistry around them. Emulsifiable concentrates rely on their emulsifiers staying intact, which can fail if they're introduced too early into water that's already carrying dissolved product. Add products in the wrong sequence and you risk physical incompatibility — clumping, separating, foaming — or chemical incompatibility that silently reduces how well the pesticide works, without any visible sign in the tank.
University of Nebraska–Lincoln Extension (G2350) lays out both failure modes plainly: physical incompatibility shows up as solidification, fizzing, foaming, clotting, settling, or heat; chemical incompatibility can reduce pesticide effectiveness with no visual clue at all. That second kind is the more expensive mistake — you spray a full tank, see no obvious problem, and get a weaker result than the label promised.
The Mixing Sequence
The classic shorthand is WALES — Water-soluble packets, Agitation throughout, Liquid flowables, Emulsifiable concentrates, Surfactants last. Virginia Tech Extension (BSE-351) still references this sequence directly. Newer formulations have made the acronym a rough guide rather than a strict rule, so UNL Extension's updated sequence is worth using as the working order:
- Water-soluble packets or bags — these need to fully dissolve before anything else goes in.
- Wettable powders
- Dry flowables / water-dispersible granules
- Liquid flowables or soluble concentrates
- Emulsifiable concentrates or microencapsulated formulations
- Surfactants, adjuvants, or oils — always last, right before topping off with the remaining water.
Agitate continuously through the whole sequence, not just at the end. Give each product a few minutes to fully incorporate before adding the next one. Both extensions are explicit that the product label overrides this general order — if a label specifies a different mixing sequence for that exact combination, follow the label. It's a legal document, and manufacturers test compatibility for their own formulations more specifically than any general chart can.
Running the Jar Test
Before you commit a full tank, scale the whole mix down into a quart jar. The proportions matter more than the volume — you're recreating your actual tank ratio in miniature.
- Fill the jar about a third to half full with the same carrier water you'll use in the tank (or diluted fertilizer, if that's your carrier).
- Add each product in the sequence above, in proportion to your planned tank mix, shaking or stirring between each addition.
- Once everything's in, top off with the remaining carrier to a fixed volume — 100 mL or a full quart, whatever's convenient to standardize.
- Let it stand for 10 to 15 minutes (UNL's protocol allows up to 30 for a more conservative check).
- Look at it. A mix that stays uniform — no layering, no clumps, no floating film, no heat or unusual odor — is compatible. Anything else means don't load the full tank with that combination.
If the jar test comes back clean, you've confirmed the physical compatibility. Chemical incompatibility — reduced efficacy with no visible sign — is harder to catch this way; UNL Extension notes that a small test-plot application is the only way to catch that kind of interaction before you commit the whole tank.
Reading a Failed Jar Test
- Layering or separation — the products haven't emulsified together. Usually a sign the sequence was wrong or an emulsifiable concentrate was added before enough water/agitation was established.
- Clumping or solid particles — often a wettable powder that didn't get time to disperse before something else was added.
- Foaming beyond a thin surface layer — can indicate a surfactant conflict, especially if it was added too early.
- Heat, strong odor, or fizzing — a chemical reaction is happening. Don't use this combination regardless of what the jar looks like once it settles.
Any of these outcomes means: don't scale it up. Rinse the jar, re-check label mixing instructions for that specific combination, and consider whether the products need to go down as separate applications instead of one tank.
Putting It Together With Your Tank Mix
Compatibility is a yes/no question you answer once, with a jar, before you touch the sprayer. Once you know the mix is clean, the Tank Mix Calculator handles the part that's pure arithmetic — how much of each product per full tank and per partial last load, based on your area, tank size, and calibrated output rate. If you haven't calibrated your sprayer's output rate yet, that's the other variable the calculator walks you through — an inline helper turns a measured test pass into your actual gallons-per-1,000-sq-ft number.
Frequently asked questions
What does WALES stand for in tank mixing?
WALES stands for Water-soluble packets, Agitation, Liquid flowables, Emulsifiable concentrates, and Surfactants — the general order to add products to a spray tank. It's a useful shorthand, though extension sources note that modern formulations have made a more detailed formulation-type sequence (wettable powders and dry flowables before liquids, EC and microencapsulated products before surfactants) more reliable than the acronym alone.
Do I need to jar test every tank mix, even ones I've used before?
Test any new combination of products you haven't mixed together before, and re-test if you switch brands or formulations of a product you normally use — manufacturers can change formulations without changing the product name. A combination you've run successfully all season doesn't need a jar test every single time, but a new pairing always does.
What carrier water should I use for the jar test?
Use the same water source and, if applicable, the same diluted fertilizer or other carrier you'll actually load into the tank. Water hardness and pH can affect compatibility, so testing with tap water when your tank draws from a pond or well won't catch problems specific to your actual carrier.
Can I still use a tank mix that shows minor separation in the jar test?
No — treat any layering, clumping, or foam beyond a thin surface film as a failed test. Minor separation in a jar scales up to a real problem in a 25- or 100-gallon tank, and you won't be able to fix it once it's loaded. Re-sequence the mix, drop a product, or apply separately instead.
Does the mixing order in this guide override the product label?
No — the label always wins. If a product label specifies a different mixing order or explicitly states it's incompatible with another product class, follow the label over any general sequence, including the one in this guide. WALES and similar sequences are a default for combinations the labels don't address directly.
Last reviewed: September 2026. This guide is informational only and does not constitute professional agronomic advice — always follow product label instructions, which are legally binding and take precedence over general mixing guidance.