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16 Steps to Better Spraying
Here’s what you can do to optimize efficiency and to minimize off-target drift.
1. Read the Label
Chemical manufacturers are starting to specify droplet size on product labels.
“As more and more chemical manufacturers start incorporating more information into the label, it will be critical that you study the label in detail,” says Bob Wolf, co-owner of Wolf Consulting and Research.
Reading the label gives you information required for optimal pest control. The label also contains information to curb off-target movement.
2. Think About Spray Nozzles
You are faced with the challenge of selecting proper nozzles, ones that provide necessary spray coverage to kill the targeted pest yet minimize drift.
“We commonly think it’s a good idea to have small droplets to get better coverage, and oftentimes in the real world, we’re working in environmental scenarios. Those smaller droplets will drift,” says Wolf.
Small drops give better coverage to control your pest target.
“The challenge then to the application is to get those droplets into the target area and not have them move off target,” he says.
Fortunately, there are nozzles built and engineered to reduce drift.
3. Pick the Best Nozzle
4. Use a Pattern Check
What does a spray-pattern check do? It checks your spray pattern, obviously!
One tool is the Redball Pattern Check, which tests the pattern with the sprayer holding water. You place the pattern check on the ground and spray on top of it. When it’s held up, the pattern is revealed. Through the pattern check, you can confirm that you have the proper nozzle spacing and boom height.
5. Look for Proper Pattern-Check Alignment
The pattern check shows that proper spacing and the proper height above the target can boost spray-pattern uniformity.
If a nozzle is out of whack, the tool indicates it by a misaligned red ball.
“You need to correct that immediately,” says Wolf. “Nozzle blockage can prevent the sprayer pattern from being as uniform as it could be.”
An ideal spray pattern should have all the balls at the same height across the Redball Pattern Check.
“It’s probably impossible to have a completely level spray, but something reasonably level should be accomplished,” says Wolf.
So what harm does a faulty nozzle cause? You’ll see spotty pesticide coverage. Weed streaks across the field are a dead giveaway. Ditto for disease streaks after you’ve applied a fungicide. Chewed-up or dying spots across a field after an insect application are giveaways, too.
“It is critical that you make sure each nozzle is spraying uniformly by itself individually and in conjunction with the nozzle next to it,” says Wolf.
There is a simple way to check nozzles. In a perfect world, it would be great to carry a pattern-check board with you everywhere. That won’t always happen, though.
The good news is you can eyeball a faulty nozzle by putting water in the spray tank from time to time and inspecting each individual nozzle. Check new nozzles, since newness isn’t a guarantee it won’t be faulty.
After you’re done inspecting each nozzle, drive across the lot and spray. Get out on the platform and watch the sprayed area dry. If it dries evenly, then you’ve sprayed evenly. If it dries in streaks, you’ve sprayed unevenly, says Wolf. After this test, a faulty nozzle will be obvious.
6. Space Nozzles Properly
Have a one-to-one relationship between boom height and nozzle spacing. For example:
- 15-inch boom height = 15-inch nozzle spacing. Or
- 20-inch boom height = 20-inch nozzle spacing.
These boom heights might seem low to you. Still, preventing off-target movement means you’ll likely have to lower your boom more than you have been.
“The challenge in the industry is that a lot of people are using their booms higher. This can result in more drift and could quite possibly also lead to some poorer coverage if the boom gets too high,” says Wolf.
Remember that when you’re spraying postemergent herbicide, you’re applying product to a growing crop and weed canopy. So, figure the height as above the canopy, not the ground.
7. Calibrate Your Sprayer
Calibration helps you get the right amount of product on the weed, insect, or fungi you’re targeting. Next, it prevents you from overapplying chemical that can escape into the environment. You have flexibility with how to configure the volume by being selective of speed, pressure, and nozzle size, says Wolf.
“Calibration of the sprayer should happen at least once a season, but I would like to see it occur much more often,” says Wolf. He advises calibration any time you change nozzles, solution, or pressure.
Calibration begins with reading the label. The label gives an indication of the gallons of the solution per acre.
8. Consider a Quick Way to Calibrate
The SpotOn sprayer calibrator that’s designed and manufactured by Illinois-based Innoquest is one way. It’s a way to obtain accurate calibration results in 10 to 12 seconds per nozzle.
That’s a fraction of the 1.5 hours that it can take to calibrate a 120-foot boom with 20-inch spacing and 73 nozzles by using a method that sprays water into an empty jug while it’s timed with a stopwatch.
9. Check Wind Speed
It’s critical that you monitor wind speed during application.
“At a minimum, if it’s a big application time frame, you should probably do it at the beginning, middle, and end,” says Wolf.
Several handheld tools can be used to record wind speed.
“The measurement should be taken as near to boom release height as possible,” says Wolf. “You want to hold it down to where the boom would be.”
10. Monitor Wind Direction
Knowing wind direction is also important. “Obviously, you want to avoid spraying upwind from sensitive areas,” says Wolf.
You can detect wind direction with a rather simple tool. “It’s just a little stick with a ribbon on the end you can use to get a sense of the direction of the wind.”
This can be supplemented with a simple handheld compass to verify wind direction. This double reading would aid you if you are ever involved in a legal drift case.
11. Consider Using a Sprayer Weather Station
These on-board sprayer units can detect weather factors like wind speed.
“The device is set, so it can measure on-the-go wind speed,” says Wolf. “When you are working in the field, you can actually have information logged into the cab,” says Wolf. This can monitor the speed of the wind based on the direction you are going or on general field conditions during the application. It allows you to have a detailed record of the application process from beginning to end.
12. Monitor Impact of Sprayer Speed Changes
The rate controller will control the rate based upon when you speed up and slow down, maintaining a constant rate. “My primary goal as an applicator is to make sure that my rate is correct,” says Mike Flatt, operations manager for Ohio Valley Ag in Decatur, Illinois.
Understand that driving faster does affect the spray quality, and drift may occur, says Wolf.
Boosting sprayer speed can enable you to cover more acres.
Still, it can impact pressure, too. If you want to increase sprayer speed, you need to switch to a larger orifice size to eliminate any pressure increases.
“I would recommend that if you intend to drive at a higher speed, you should calibrate the sprayer at that speed to begin with,” says Wolf.
Speed fluctuations are normal, but major speed changes require changes in calibration and orifice size.
13. Check for Cross Contamination
In the good old days when you sprayed glyphosate, glyphosate, and more glyphosate to kill weeds, cross contamination from different herbicides wasn’t a concern.
Herbicide-resistant weeds changed that. You now frequently switch between different herbicide modes of action according to field weed populations. That creates cross-contamination potential.
“Any product that’s left in there becomes a source of contamination and potential for some crop injury,” says Wolf.
If you are in a situation where you need to switch chemistries between different cropping systems, you need to pay attention to product that can be trapped or captured in the system and cause problems later, he says.
Halting contamination requires much more than just cleaning out the sprayer tank.
“You need to be concerned about some features on the boom itself,” says Wolf.
For example, consider the distance from the last nozzle attachment on the boom’s end to the end of that boom section.
“Here we’re talking about a 3- or 4-inch space that could potentially lead to some contaminated product that didn’t get rinsed out,” says Wolf. “This could be pulled out into a future tank load that might cause some damage,“ he says.
Pay extra attention to these sections. If there’s an end cap, remove it and flush water through.
14. Check Hoses for Trapped Chemical
Front-fill systems are popular, but they have concerns.
“One of the challenges you’re going to have in this kind of a system is the length of hose it takes to get back into the pump and tank area,” says Wolf.
For example, some sprayers have about 10 to 12 feet of hose that runs back to the tank and then the pump system.
“As you look at that hose, think about how many gallons of product could be in there if you don’t rinse,” says Wolf. “The longer the hose, the more challenges you have for any droops in the hose where product can be trapped.”
A good triple rinse with fresh water and tank cleaner is the best way to ensure you won’t have any chemical hangover when going into your next application, says Flatt.
15. Don’t Forget About Cleaning Boom-Section Filters
One cleanout challenge concerns the filters on each boom section.
“Each one of the sections, regardless of how long it is, will have a dedicated filter,” says Wolf.
“The challenge will be for you to make sure each one of those filters is clean and does not have any contamination,” he continues. “I’ve done inspections on filters of this type in the past, and it’s not uncommon to find product or crystal of product inside the bowls of those. Strainers can even be dirty, and that can be a source of contamination later.”
16. Clean Filter Systems
Most sprayers will have some type of central filter. In many cases, it’s a larger type of stainless steel screen, such as 50 mesh.
“It’s common for product to get trapped in the bowl and in the filter itself,” says Wolf. “You may have not necessarily been on top of keeping those filtering systems clean in the past.”
This is a critical issue, since any leftover product becomes a potential source of contamination and crop injury, says Wolf.