Measuring Tank Sprayer Application Rates

If you use a pump-up tank sprayer in your garden or landscape, it is important to know the application rate that the sprayer puts out. Even most organic products have application rates listed as gallons per 1000 square feet. It is easy to test your tank sprayer and determine the application rates before you begin applying any product to your landscape.

How to Test

It’s best to do your testing on a still day. Much wind at all will affect the application rate and may give you bad numbers. You will need a few things to get started:

  • Your tank sprayer
  • A measuring
  • Chalk or tape
  • A concrete space at least 10 foot by 10 foot
  • A stopwatch
  • A bucket

The Step by Step Method

Step 1

Clean your equipment thoroughly. Disassemble the nozzle and make sure it is free of debris that will restrict the flow. Look at the end of the pickup tube, and if there is an internal screen filter on the pickup tube, clean that as well. Rinse the tank, pump, hose, and wand.

 Step 2

Find a concrete space large enough to measure off a 10 foot by 10-foot square. Mark it using chalk or tape. This 100 square foot area is your test area.

 Step 3

Fill your tank sprayer with the recommended full level of water. Pump up the tank according to the manufacturer’s specifications. Spray the water on the concrete to test the pattern. Adjust the nozzle for the pattern you want to spray. Make sure the pattern is uniform, of the desired width. The object here is to set the sprayer so that you can produce a predictable and repeatable pattern with uniform coverage.

Step 4

You may need to refill your sprayer and let your test area dry a bit before you continue. When you are ready, start your stopwatch. Starting in one corner of the test area, apply an even application of water just as if you were applying to your turfgrass or other plants. Be consistent and try not to over-apply or make the overlaps too broad. When you have completely covered the test area, stop the stopwatch.

Step 5

Using the bucket, spray water into the bucket for the same number of seconds that it took to make the application to your test area. When the time has expired, measure the ounces of water in the bucket. This is the application rate of your sprayer per 100 square feet. If you need to convert this to gallons, divide by 128. This conversion will give the sprayer application rate in gallons per 100 square feet.

Tips and Tricks

 I like to write the application rate on the tank of the sprayer with a permanent marker. Remember to mark the nozzle as well. It must be in the same position to apply the same rate. Keep your sprayer clean, and the pump seals lightly lubricated to ensure even and consistent applications.

It pays to check the application rate of your tanks sprayer at the beginning of each season.  Seals wear and leaks develop.  Over time the application rate of your tanks sprayer will change and you must adjust your mixing rate to compensate.

Links and Resources

For more information about organic gardening, lifestyles, and living, visit our website at West Texas Organic Gardening.

If you found the information here helpful, you might also find these articles on our website of interest.

Organic Growing Myths

Toss Your Tiller


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