How to Use a Backpack Sprayer

No matter how much money you’ve spent on your backpack sprayer, it won’t give you the desired result if you don’t use it right.

If you are a first-time owner of a backpack sprayer, then there are a lot of things for you to learn. In this post, to hopefully help you save some time and effort, we’ll guide you through the use process of using a backpack sprayer step-by-step, covering the main points that you need to be aware of with this type of sprayer.

How To Use A Backpack Sprayer Step-By-Step


1. Assemble your backpack sprayer

First up, assemble your backpack sprayer, following the instructions provided with the unit. If your backpack sprayer has come assembled, you may not need to do this.

While assembling, closely examine the components of the sprayer – this is to check the integrity of the pieces. If anything is broken or loose, don’t assemble the sprayer and instead contact the manufacturer for replacement.

After assembly, check if all parts are sitting tight and secure – no pieces should be loose.

2. Pick the right nozzle for the job

Be sure to pick the right spray nozzle for the job and the contamination level of your plants. If you didn’t know, the spray nozzle determines:

  • How much spray is applied to the area.
  • The coverage of the spray on the surface of the plant.
  • The proneness of the spray droplets to drifting away from the target.

The purpose of the nozzle is to separate the liquid into tiny droplets. The construction of the nozzle determines the size of the droplets and thus the factors listed above. Usually, the recommended type of sprayer nozzle is indicated on the package of the spray.

3. Calibrate the backpack sprayer

After mounting the right nozzle on your backpack sprayer, you will need to calibrate it.

There are three variables that affect the calibration of the sprayer:

  • The selected nozzle.
  • The sprayer pressure.
  • Your walking speed.

The purpose of calibration is that the crops receive just enough spray – too much spray will be wasteful and may harm your plants, whereas too little spray simply will not be able to keep pests away.

There are two ways to calibrate your backpack sprayer – the band method and the spot method. These are used for band and spot spray applications respectively.

Here’s how to calibrate your backpack sprayer for band application:

  1. Set up a calibration area that has a similar landscape to the area that you are intended to spray. The size of the calibration area is typically recommended to be 340 square feet.
  2. Choose the right sprayer nozzle for the application.
  3. Determine the width of your spray nozzle’s pattern (the band width). If using a sweeping motion to spray from side to side, make sure to measure the full width of the pattern.
  4. Divide 340 by the width of your spray pattern to determine the length of the calibration area. If your spray pattern is 6 feet wide, then the length of the calibration area will be 340 / 6 = 56.67 feet. This means that the size of the calibration area will be 56.67 by 6 feet.
  5. Fill your backpack sprayer with water.
  6. Spray the entire calibration area. You should walk forward at a comfortable speed. Use the backpack like you would in the field. While spraying, pump the pesticide at the recommended pressure.
  7. Measure the time it takes for you to cover the entire testing area. You may do a few passes and take the average time for a more reliable result.
  8. Prepare a measuring container. Spray water into the container for the same time it took you to cover the test area. Pump the sprayer the exact same way as during your test pass. The amount of water collected in the measuring container in ounces will be equal to the gallons per acre required for your land. If you collected, say, 15 ounces, then you’ll need 15 gallons per acre.
  9. Check the package of your spray to find out how much you need to apply per acre of land. This is to calculate the necessary amount of spray per gallon. For example, if the pesticide requires 15 ounces per acre and you determined that you need 15 gallons per acre in step 7, then you should add 15 ounces of pesticide to 15 gallons of water.

For an easier calculation, determine how many ounces of pesticide you will need per gallon of the mix. Simply divide the required amount of spray per gallon by the total amount of spray. In our example, this would be 15 / 15 = 1 ounces per gallon.

As for calibration for spot application, do the following:

  1. Lay out a 340 square feet calibration area that has vegetation similar to what you will actually be spraying.
  2. Pick the proper nozzle, fill the sprayer with water, and pump it to the right pressure throughout the test. You may practice outside of the calibration area to check whether the sprayer is set up properly.
  3. Mark the water level in the sprayer before starting.
  4. Treat all vegetation in the calibration area.
  5. From a container with a known amount of water, refill the backpack sprayer up until the mark. Check how much water it took to refill the sprayer. This will be your gallons per treated acre.
  6. Calculate how many ounces of pesticide to add similarly to step 9 of the band method.

4. Fill your sprayer with the solution

After you know how many ounces of pesticide you need per gallon of water, prepare the solution and fill your backpack. Make sure to pour the liquid in slowly to prevent spillage.

5. Wear the backpack sprayer

Put the backpack sprayer on your back and adjust the shoulder straps to ensure that the sprayer sits snugly. Don’t also forget to wear safety equipment, including eye protection, chemical-resistant gloves, work coveralls, and, if necessary, a respirator and chemical-resistant clothing.

6. Spray the pesticide on your crops

Finally, it’s spraying time.

First off, pump the handle for 10-15 times and test the sprayer. Then, pull the trigger to spray the pesticide on the desired area, ensuring uniform coverage. And every 5 seconds or so, pump the handle to ensure constant pressure inside the sprayer.

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