Everything you need to know to make your farm’s chem applications successful—whatever you spray, whenever you spray it
The ins and outs of getting the spraying done, from owning and operating your sprayer equipment to selecting and purchasing chem and making the most out of well-timed applications.
Did your father or grandfather teach you how to use a sprayer and make chemical applications on your farming operation? Did you learn how to fill and mix the tank from watching a pro up close? Maybe you studied agronomy or crop science to learn the ins and outs of active ingredients and how they interact in the tank and on plants.
If so, you might be among the lucky few. In years past, many growers left the job of spraying chemical applications to custom applicators. Not so today. Many growers prefer to own their own spraying equipment, thanks to cost savings and the flexibility of making more timely applications when crops need them. These are just a few reasons that owning and operating a sprayer allows farmers to gain more control and independence over the management practices on their farm.
Why we spray: Getting the crop off to a solid start
We don’t have to tell you that spraying is one of the most important activities regularly done on a crop operation. That’s why we’ve written this story with tips, best practices and management steps for DIY farmers who want to learn what the pros know, and how they do what they do, to make the most out of whatever you’re spraying, whenever you’re spraying it.
When we start looking forward to each growing season, it’s easy to get excited about putting seeds in the ground at the start or seeing those yield numbers come in at the end. But spraying is an equally important part of making sure that every crop has a chance at success.
- Controlling the pressures before they start. Without the preventative control of herbicides, insecticides and fungicides, we’d miss out on clean fields to plant into and healthy crops to combine. Making sure that you have a solid plan (with built-in flexibility!) for each crop you’ll spraying that season is essential, from proper sprayer maintenance between sprays to making sure the field is in the best condition based on the application you want to make.
- Managing in-season needs. Insecticides and fungicides do the work of protecting all your crop has to offer. While some of the chemistries we use are preventative (see #1), and should be applied before the crop might be showing signs of disease or pests, others have been developed to be suppressive if your crops do begin to show signs of pressure. Both have their place in the field, depending on the pressures you face and when they may develop in the crop’s growth cycle. Make sure you’re keeping bugs and disease at bay by scouting regularly and taking making the necessary applications to keep pests out of your fields. Learn about: early season soybean pests and early season corn pests.
- Reducing competition. By reducing a crop’s access to nutrients, water and sunlight, out-of-control weeds can keep your crop from reaching its full potential. Control the competition by taking the extra steps to keep resistant weeds, volunteer corn or any number of pests from getting a foothold in your fields.
And in every scenario, always, always, always read and follow label use instructions.
What’s going in the tank
What’s going in and what’s going down.
Modes of action: What you are applying and where
There are nearly 30 herbicide MOAs, with another 10 for insecticides and 15 for fungicides. MOAs explain how chemicals control their target pests. Knowing your MOAs can help you choose the best herbicide, pesticide or fungicide (and prevent resistance) on your farm.
Selecting the right chem: Branded versus generic chemicals
Thousands of farmers use generic products on hundreds of crops, but many farmers are still unsure about which products are generic, which ones are name brand, and how to know the difference. They’re also unsure of whether or not it matters if they’re buying branded or generic chemicals.
The reality is that though generic products are not identical to their branded equivalents, they tend to be very similar in terms of performance. The EPA states that a generic product has to have the same technical make-up as the branded version, meaning the active ingredient is the same. Generic and branded products are often manufactured by the same companies.
Rates and tank mixing: How much you’re putting down
Many farmers consider whether or not it’s the most efficient way (or the best value) to purchase a premix or tank mix your chemicals. Premixes call for less handling by the farmer and are professionally prepared based on the highest use rates of the region. However, the application timing may not always be preferable for the current weed growth stages and there may be issues in certain soil types and conditions. Tank mixes can be tailored specifically to a farmer’s needs, but require a greater understanding of the chemicals. They do allow for a more customized timing, however, they also require more attention to detail and safety precautions.
Extras in the tank
Beyond the active ingredients you’re putting down, there are a number of tank-mix extras that you might find useful. They can help with crop health, as biostimulants do, or like adjuvants, can help your chem sprays to perform and keep your tank mix from gunking up.
Biostimulants stimulate natural plant process that improve nutrient uptake (making your fertility applications more efficient) as well as environmental stress tolerance and can even improve overall crop quality.
Adjuvants are added to a spray tank mix specifically to ensure the spray solution does what it is intended to; it’s a non-pesticide product that improves handling characteristics, like spreading, penetration or droplet size, and can reduce application issues that happen to chemicals just by being mixed together in the tank. Examples of adjuvants include surfactants, oils, buffers, and defoaming agents. Most defoamers work best before foam actually begins to form. If you’re concerned about your tank mix compatibility, don’t be afraid to perform a jar test or read our blog "Adjuvants 101: Understanding the Extras in Your Tank".
Whatever winds up in the sprayer to apply—herbicide, insecticide or fungicide—understanding tank mixing order can eliminate any number of potential problems you might encounter during spray solution prep.
Real talk about resistance
Weed resistance is making the use of residual herbicides a hot topic. These products can be used to stop weeds before they emerge, and they’re so named for the long-lasting efficacy period. Residuals have become important in fields where herbicide-resistant weeds have become a concern. Using a residual with multiple modes of action allows for a variety of weeds to be controlled, and for resistant weeds to be targeted from multiple pathways, minimizing early competition for the crop.
Getting the sprayer equipment ready to roll
Before the sprayer even hits the field, there are a few steps you can take ensure that you make the most of each pass.
Take time to get to know your spray equipment. Most boom sprayers are made up of the same basic components – tank, agitator, control valves and gauges, hoses, pump, and strainers. It’s important to give every component a precursory look to prevent leaks and failure in the system.
Nozzles and spray patterns
Nozzles play a vital role in moving what’s in your tank to where it needs to go, so choosing the right ones is important. Depending on your spray method, application rate and ground speed, there are a variety of spray patterns, angles, shapes and sizes to choose from. Not every nozzle works for every spray, so it’s important to know your needs and what tools will best support them. Droplet size and water volume needs vary by MOA, and the product labels are your best source of information on this topic.
Know what’s happening in the field before you head out for a spray
There are four factors that determine the success of a chemical application: mode of action, canopy, water volume and target type/droplet behavior.
Plant size and shape makes a difference how you spray
An early season canopy doesn’t provide much of a barrier for target pests, so it may require a lower water volume than a denser, more mature canopy, where more water is required to reach the bottom layers. Thus, more layers require more water, resulting in coarser sprays. Along those same lines, less water volume makes finer sprays more necessary to ensure consistent coverage.
Larger more horizontal surfaces are better suited for coarser sprays, whereas smaller, more upright plants need finer sprays. Many broadleaf weeds are well suited for larger, coarser sprays. Grasses and young broadleaf weeds need finer sprays for effective control.
Crop growth stages
It’s important to time weed and disease management with crop growth, because the crop’s growth and development impacts your timing for post-emergence herbicide applications, as well as when you can apply insecticides or fungicides per label instructions. All herbicide products provide information on the limits of an application on the product’s label. In corn and soybeans, these limits can be by growth stage, height of crop or days before harvest interval required.
Avoiding spray drift at all cost
Fine sprays, however, can lead to an increased chance of drift, and it is important to do all you can to mitigate your risk of spray drift. Paying special attention to—and keep excellent records of—environmental conditions is key here as well. Temperature inversion (when air close to the ground is denser and cooler than the air higher up) is an often-overlooked scenario that can lead to a high risk of drift. Ground fog and a lack of air movement are two indicators that you might be in an inversion situation.
Warm weather can impact how spray applications will behave. For example, translocated herbicides, including glyphosate, may take longer to act in warm weather or may not prove to be as effective, due to the way they interact with the plant. Special attention should also be paid to contact herbicides; while the warmer temps may lead to improved weed control with these products, they can also increase the risk of crop injury. And PPO-inhibitors, like sulfentrazone, should be used cautiously as temperatures rise above 85 degrees.
Cold weather, for the most part, has a less concerning impact on crops, but comes with its own considerations. As long as they have received enough moisture to incorporate into the topsoil, residual herbicides should retain their efficacy in even while temperatures are low. Glyphosate is, again, an exception—it will simply take longer to show any action in colder temperatures.
Prepping for the next chem application
Once you’re finished in the field, the final big step happens: cleaning up the sprayer for its next go.
Leftover residue from a previous application can gum up your next spray or worse, damage your crop, so the key here is prevention. Removing most of the mixture, diluting anything remaining in the tank and making sure that everything that encountered the spray gets cleaned are simple ways to make sure you have your sprayer ready to head out again.
Keep a sprayer maintenance checklist, from pumps and hoses to filters, gauges and nozzles, know how to inspect and maintain your equipment to keep it calibrated and working properly. Make sure to note when the last cleanout occurred, where, what was cleaned and what products were used for the cleanout based on the last application made.
And you can’t forget the importance of reducing your own exposure. Always work with your spray solutions in a well-ventilated area, and make sure you’re taking the necessary precautions. Long sleeves, pants, socks, shoes, gloves and protective eyewear should all be part of your standard personal protective equipment (PPE). Some product labels require the use of additional PPE, depending on the product’s use and toxicity.
Finishing up the fieldwork and spraying season
At the end of the day, the most important thing you can do to ensure your spray applications are successful is to plan well, but be flexible. It is essential to develop plans and processes that work, but as with everything in farming, cropping changes, unexpected pests and shifting chemical needs can always lead to adjustments. Be ready to embrace them.