Jar Test
Scale your field rates down to a jar.
Enter your spray volume and product rates, and the calculator works out exactly how much of each product, and how much water, to put in a single test jar before you commit to a full tank.
Test Setup
Products and Rates
| # | Product | Rate | Unit | Per jar |
|---|
Mix Breakdown
| Product | Field Rate | Amount |
|---|
Analysis
Always jar test before tank mixing biologicals with synthetics. Watch for separation, gel, curdling, or color change at 5, 30, and 60 minutes.
Running the Test
A jar test is a small scale rehearsal of the tank. It costs a few minutes and a mason jar, and it catches the mixes that would otherwise plug screens, curdle in the sump, or cost a day of cleanout in the middle of a spray window. Biologicals in particular are sensitive to pH, salt load, and hard water, so anything going out with a live product is worth checking first.
Follow the same sequence you would in the tank. A common order is water conditioners first, then dry formulations, then flowables and suspensions, then emulsifiable concentrates, then solutions and adjuvants, with biologicals added last. Agitate between every addition, exactly as the sprayer would.
- Fill the jar about half full with the same water you will spray, at the same temperature.
- Add each product in tank order, using the mL amounts this calculator gives you.
- Cap and invert about twenty times after each addition. Do not shake hard, that introduces foam that reads like a failure.
- Top up to your jar volume with the remaining water.
- Let it stand and check at 5, 30, and 60 minutes.
Look for separation into layers, an oily film on the surface, gel or paste on the bottom, curdling that looks like cottage cheese, clumps that do not re-suspend when you invert the jar, heat, or gas building up under the lid. Fine sediment that disperses on inversion is usually acceptable. Anything that will not go back into suspension is not.
The scale factor is your jar volume divided by the volume of spray one acre receives. At 20 gallons per acre, one acre gets 75,708 mL, so an 800 mL jar represents about 0.0106 of an acre. Every product rate is converted to mL and multiplied by that factor. Rates given per 100 gallons are scaled by your spray volume first, and percent by volume rates are taken as a share of the whole jar.
Dry products are reported in grams rather than mL, since a weight cannot be converted to a volume without knowing the density. Weigh those on a gram scale.
A jar test shows physical compatibility only. It says nothing about whether the mix will be effective, whether it will burn the crop, or whether the label permits it. The label is always the final word. Water quality also matters more than most mixes admit, so run the test with water from the same source you will fill from.
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