What temperature is the water you fill your sprayer with in the fall or spring? What does it matter? Do you add ammonium sulfate? Why should you spend money on it?
These are just a few of the questions Fred Whitford addressed at a field day at Remke Farms near Harlan, Ind., recently. Whitford is the director of Purdue University Pesticide Programs.
Here are six tips for keeping your sprayer working efficiently and getting the most out of your herbicides.
1. Water temperature affects the ability of a spray solution to kill weeds. If water temperature is below 41 degrees F, your spray solution won’t be as effective at killing weeds, Whitford says. At least one large chemical dealer in Indiana raises water temperature to be used for spray solutions to 60 degrees just to avoid this potential issue.
2. Hard water affects effectiveness of some herbicides. If you don’t add ammonium sulfate to the spray mix and your water is hard, you may not get the weed kill you expect. That’s especially true with glyphosate, Whitford says.
3. Clean the tank out carefully, following the prescribed steps. That means the first rinse needs to be sprayed back over the crop instead of dumped on the driveway or anywhere else, Whitford insists. It’s unethical, if not criminal, to dump chemical where you know there is a possibility that it might reach a creek or other waterway.
4. Clean screens and plastic surfaces carefully. Some herbicides have an affinity to tie up in plastic surfaces, and may be pulled out of those surfaces later by a different herbicide. It’s one scenario that can result in contamination of a spray batch with a chemical that isn’t supposed to be in the batch. Cleaning screens is also essential. Be sure you know where every screen is located, and clean and rinse them all, Whitford advises.
5. Mixing order can matter with chemicals. Check labels and consult with experts before you start dumping chemicals into the spray tank, Whitford says. In some cases, it can make a difference which materials are added to the spray tank first. Certain chemicals mix better together than others, he adds. If you don’t follow the order correctly, there’s a bigger chance that mixing won’t be complete. When that happens, solids can form that wind up in screens or other places hard to clean out with normal cleaning procedures.
6. Look for dead zones along booms where materials can accumulate and clean them. One of the most notorious places to find gunk that has accumulated over time is in dead spaces at the end of booms, Whitford says. He believes it is crucial to remove the caps and check those spots. “First, they need to pass the eye test,” he says. “In many cases you can tell right away that these areas have a buildup of contaminants, and that they need to be cleaned thoroughly.”
Some companies are now trying designs that eliminate such dead zones. But until these products are available, be sure to clean the dead spaces, Whitford concludes.