Category: Cleaning & Maintenance

All hort articles on sprayer cleaning and maintenance.

Operator Safety: How to Avoid Pesticide Hazards
A Veteran Applicator’s Questions about Pesticide Handling
Time and again, after years of working with dozens of different chemicals, I would wonder to myself “How dangerous is this chemical?”, “Is glyphosate as safe as they say it is?”, “How do I find out what type of safety gear I need while handling this chemical?”
Beyond the agrichemical dealer, ag. consultants, and university or government ag. extension specialists, a quick internet search reveals many sources of pesticide information. Collectively they identify the active ingredient(s) in formulated products, they detail which pests are best controlled by the pesticide, and they provide instruction for application. But it’s more difficult to find consistent, practical information about safe pesticide handling. Sometimes it’s excessive to the point of being impractical (try finding actual “chemical proof” gloves), and sometimes it’s minimal and vague – it depends where you look. No matter the level of precaution, pesticide safety is time consuming and involves some fussing, but it is the hallmark of responsible pesticide use. Just as we ensure that we are applying “safe rates” when spraying chemicals, we must also ensure we are respecting our own well-being while handling chemicals.
In Canada, the Pesticide Regulatory Directorate (PRD) is charged with protecting human health and safety by monitoring pesticides that are sold in this country. According to the Federal Pest Control Products Act all pesticides sold in Canada must be registered with the PRD. There’s a very nice overview of how that process works here. It is during this registration process that pesticide handling precautions are identified for the label. Further classification may take place under provincial acts.
All pesticides are designed to disrupt, repel, control or kill living organisms, but when it comes to safe handling, insecticides receive the most attention. This is because herbicides and fungicides target biochemical pathways that only exist in plants or fungi. However, most pesticides can be hazardous if they are not handled correctly. The handling precautions that appear on the label are based on five factors.
Five factors that affect handling precautions:
1. Pesticide Family
This factor is the broadest way to categorize potential risk to the handler. Generally, herbicides and fungicides are considered safer than insecticides, but there are notable exceptions. Do not rely solely on the pesticide family when making decisions on pesticide handling.
2. Pesticide Mode of Action
The mode of action gives further detail into how a pesticide should be handled. Modes of action that inhibit biochemical pathways that exist in the target pest, but not in mammals (people, in particular), have lower acute toxicities. Examples include herbicides that inhibit enzymes involved in amino acid synthesis or in photosynthesis – these enzymes do not exist in mammals. However, once again, there are always exceptions. Do not rely solely on mode of action when making decisions on pesticide handling.
3. Pesticide Formulation & Route of Entry
Pesticide formulation affects how a product can potentially be absorbed into the body. Emulsifiable Concentrates (ECs), for example, have higher rates of absorption than solutions or dry products. When it comes to the route of entry, dermal contact is considered safer than inhalation or ingestion. However, not all parts of your skin are created equal, and the point of dermal contact on the body matters a great deal.
4. Pesticide Toxicity
Taken collectively, the first three factors form the overall toxicity of the pesticide. The level of toxicity cannot be predicted – it has to be tested. The LD₅₀ (defined below) values that are reported for a pesticide come from standardized experiments such as animal feeding. Although the chosen species (usually white rats for mammalian endpoints) are known to be similar to humans in their response, there is still the possibility of error. Nevertheless, toxicity forms an important basis for establishing handling precautions.
5. Operator Exposure
People handle toxic substances every day. Household bleach, for example is surprisingly toxic, and yet it can be readily found on kitchen shelves in many homes. The risk of being harmed by a toxic product can only be determined by the likelihood of exposure. While it is possible someone might accidentally consume a hazardous dose of bleach, it’s improbable. Exposure does not just refer to a single exposure to a substance – repeated exposures to small doses of a toxic substance can have a cumulative effect. The goal when handling any pesticide is to minimize exposure, but it becomes even more critical when that pesticide is highly toxic. Together, exposure and toxicity form the basis for risk.
Risk = Hazard x Exposure
Studies have shown that exposure is greatest for handlers of agricultural pesticides during the mixing and loading phase of spraying. During this phase, the risk to the handler may be increased due to:
- physical stress
- the denial of risk
- a negative opinion of personal protective equipment (PPE)
The main method of pesticide exposure is dermal, and many of the surfaces on a piece of equipment are already contaminated.
Health effects of pesticides: Acute and Chronic
Acute: short term
High exposure, resulting in immediate reaction due to a high dosage of pesticide exposure. The severity depends on the toxicity of the molecule and entry into the body (dermal, oral, eyes, etc.). The most common acute reaction is skin irritation, although in certain cases respiratory, digestive, and neurological systems may be affected. Organophosphate (e.g. Lorsban, Malathion) and carbamate (e.g. Sevin, Lannate) insecticides inhibit the cholinesterase enzyme, which is found in humans and affects nerve function. Frequent users of these insecticides undergo regular blood tests to ensure their levels are normal.
Chronic: long term
Chronic affects are more prolonged as they are usually due to lower doses of pesticide exposure over a longer period of time. Although some rare cancers and disruption of the reproductive system have shown to be related to this type of exposure, when the general population and farming population have been compared in studies, the farming population has shown an under-representation in the majority of cancers. In the cases were reproductive malfunctions were observed, a different cause of the malfunction, such as genetic offset, was most often observed in these situations. However, cancer types such as skin cancer and brain cancer were overrepresented in the farming community. A study in France has shown that the onset of neurological disorders in Agriculture communities shows a strong connection between Parkinson’s disease and exposure to pesticides.
Label Information
The majority of information needed to safely handle pesticides is found on the label. Pesticide labels are legal documents, meaning they can be enforced by the federal government. The problem is that most sprayer operators rarely look at the label as they are not very reader friendly and easy to skim through. Most pesticide boxes even have the recommended rate, or acres/case on the side of the box now, so there is even less reason to look at the label.
LD₅₀– the dose of pesticide in mg per kg of the test animals body weight that is lethal to 50 percent of the group of test animals. For example, if the pesticide has an acute oral LD₅₀ value of 1000 mg/kg, and the test animals each weigh 1 kg, then 50 percent of the animals would die if they each ate 1000 mg of pesticide at once. A 100 kg animal would need to ingest 100,000 mg (100 g) of the pesticide for the same effect. LD₅₀ is often expressed by the route of entry – dermal, inhalation, acute oral (ingestion) are the main examples.
Degree of Risk and Hazard Symbols
Two Factors that Determine the Appropriate Level of PPE
1. The Hazard Rating (above) incorporates the minimum protection generally required for a substance with the rating.
2. The Label Recommendations will usually give the additional specific protective clothing and equipment needs for an applicator.
Degree of Exposure
This increases as the length of each pesticide application increases. As the number of pesticide applications increases, the time between exposures decreases. If an operator becomes exposed to spray, dust or fumes the degree of exposure increases. Essentially, more protective wear is needed as the degree of exposure becomes greater.
Knowledge
This encompasses all of the above information. In order for a pesticide applicator to avoid injury or the chances of adverse effects on the body, a pesticide applicator must be knowledgeable about pesticides. It can be overwhelming for an applicator to sort through all of the information on the label or on-line regarding pesticides. So much so, that most often applicators avoid the information altogether. Ongoing training and learning will ensure that they are effective in their work. Many aspects of pest control change continuously, as new studies are conducted on the effects of pesticide exposure.
A Safety Data Sheet (SDS) is available for each pesticides registered, and these are usually linked on manufacturers’ websites. It can be eye-opening what types of toxicity tests are done, and what the results are.
Denial that pesticides can potentially cause harm is also a major flaw in the behaviour of applicators. Maintaining a safe work environment and practicing personal safety will reduce the chances of an applicator experiencing serious injury throughout their farming career.
Unknowns
There is very little certainty in toxicology. For one, most testing is done using acute oral and dermal dosing. Basically, toxicologists expose test animals to the neat active ingredient and watch what happens. There is a lot of missing information – what about formulant like solvents, and surfactants? What about synergies in tank mixes? Some, but not all of these, undergo testing. We also have much less information on chronic (long-term) effects, and can only simulate these in quasi long-range tests. In addition, toxicological methodologies and statistical approaches can vary, and we should not be surprised that some reports disagree, and that there are outright conflicts between toxicologists and epidemiologists (scientists that study patterns of health in populations). Regulators are aware of these shortcomings and often use safety factors to account for them. But those of us that use these products regularly, the message is simple: be cautious, and protect yourself.
Avoid Cross-Contamination
Disposable nitrile gloves are the product of choice for handling pesticides. But one of the most common problems with the use of gloves is cross-contamination. You’re handling product with your gloves on, touching containers, hoses, valves, and couplers. When you’re done, you climb back into the cab where you take off your gloves. Later, someone climbs up into the cab to talk to you, using the railing and operating the door handle without gloves. Guess what’s on their hands? Even later, you put away the hose without gloves and return to the sprayer. Now it’s on the steering wheel and all the levers. There are a few solutions:
- Double-glove so you can take the dirty outside glove off and still be protected.
- Wipe down surfaces that you might touch with gloved or bare hands daily.
- If using non-disposable gloves, avoid lined gloves and rinse the insides out daily.
Learn More
If you would like to learn more about pesticide safety, or to obtain pesticide application training, the Pesticide Applicator License can be obtained from the Ministry of Agriculture. This course offers in depth, valuable safety information for applicators, as well as general knowledge for pesticide applicators. The Pesticide Regulatory Directorate provides workers, employers, and the general public with a wide range of pesticide information. The PRD can be contacted from anywhere in Canada toll free at: 1-800-267-6315
Download this Quick Reference Guide for commonly used herbicides. Print, laminate and post it at the fill station or pesticide storage area for easy reference. Also, grab a copy of Health Canada’s “Stay Safe when using Pesticides” factsheet.
Sources
May 11, 2026
Cleaning Your Sprayer
We all know the importance of cleaning out a sprayer. It protects a sensitive crop. It protects people working with the sprayer. It protects the sprayer and its components. But cleaning the sprayer is a pain. Here are some tips to make it easier.
Some herbicide label instructions are cumbersome, requiring many flushes with full tanks of water. Many applicators look for shortcuts and hope they get away with it. It doesn’t have to be guesswork. The following is a checklist that may help.
Be Prepared
A few supplies can help ensure a clean sprayer tank.
- A defoaming agent saves water and time
- A cleaning agent (commercial products, or simple household ammonia) is useful, and recommended, for Group 2 products except the imidazolinones.
- A supply of clean water, preferably with its own pump, and a pressurized spray hose helps clean the sprayer inside and out.
- A wash-down nozzle (whose flow requirements can be met by the clean water pump) can automate the tank wash-down.
- A bucket and brush for rinsing screens is very useful.
Products to Watch:
The products most frequently implicated in sprayer contamination are two members of the Group 2 modes of action: the sulfonyl ureas (e.g., thifensulfuron (Refine) and tribenuron (Express)), and the triazolopyrimidines (e.g., florasulam (Frontline, PrePass) and pyroxsulam (Simplicity)). Since these herbicides dissolve better at higher pH, proper cleanout usually requires ammonia, a weak base that raises the solution pH. The third member of Group 2 products, the imidazolinones (imazethapyr (Pursuit), imazamox (Solo, Odyssey), imazamethabenz (Assert), imazamox (Ares, Adrenalin, Altitude or Viper)), tend not be implicated in as many residue issues, and don’t require ammonia for cleanout.
Be Prompt and Thorough
Remove pesticide from mixing and spray equipment immediately after spraying – it makes the job easier. The main areas of concern are the tank wall, sump, plumbing (including boom ends), and filters. First, spray the tank completely empty while still in the field. It’s sometimes OK to cover previously sprayed areas – all herbicides must be crop-safe at twice the label rate to be registered by the PMRA. Take care with residual products that may create problems down the road. Reduce the rate or choose a fallow field to be certain. Second, add 10 x the sump’s remnant of clean water, circulate, ensuring agitation is on, and spray it out in the field as well. Repeat. These two rinsing steps will take care of the majority of the cleaning and won’t take very long. The less remaining volume there is in your tank after the pump draws air, the less water is needed to dilute this remainder to an acceptable concentration. Having a clean water tank on the sprayer and a wash-down nozzle makes this job easier.
Visual Inspection
Herbicide residue may precipitate out of solution in some parts of the sprayer or plumbing. A thorough visual inspection can identify these problem areas and ensure that they are cleaned properly.
Tank Wall
Removal of residues from tank walls is best accomplished with a direct, pressurized spray. Make sure all parts of the wall have been in contact with clean water. Use a wash-down nozzle if it provides complete and vigorous coverage of the interior tank surface.
Sump
Empty the sump as completely as possible by spraying it out. Any spray liquid or herbicide concentrate remaining in the sump area will be re-circulated in the sprayer. The only way to remove any remaining herbicide is through dilution by repeatedly adding water, and leaving as small a remainder as possible.
Plumbing and Boom
Plumbing can be a significant reservoir of herbicide residue. Removal from plumbing can be achieved by pumping clean water through the boom while ensuring that all return and agitation lines also receive clean water and all residue is flushed out. This may require opening and closing various valves several times, and repeating the process with new batches of clean water. Boom ends can extend up to 6” beyond the last nozzle at each end of each boom section. These ends must be flushed to removed trapped residue. A useful product that does this automatically is the Pentair Hypro Express Nozzle Body End Cap, or better yet, consider recirculating booms.
Dilution
The most effective use of a volume of rinse water is to divide it equally across several repeat washes. Assuming a 10 gallon sump remainder, three washes with 30 gal each are as effective as two washes with 70 gallons each, and equal a single 600 gal wash.
It’s even more efficient to use a separate clean water pump, introducing clean water as the rinsate is sprayed out. This saves water and time, and results in even more dilution.
Filters
Nozzle screens and in-line filters can be a significant reservoir for undiluted or undissolved herbicide and are one of the most overlooked parts of sprayer decontamination. Remove all filters and nozzle screens and thoroughly clean these with fresh water. Run clean water through plumbing leading to the screens.
Nozzle Bodies
Nozzle bodies can harbour herbicide mixture. When cleaning a spray boom, rotate through all nozzles in a multiple body to ensure clean water reaches all parts of these assemblies. Remove screens that may have been used with herbicide.
Tank Cleaning Adjuvants
Adjuvants such as ammonia can assist the tank decontamination process, especially with sulfonyl urea and triazolopyrimidine-containing products. Ammonia does not neutralize herbicides, but it does raise the pH of the cleaning solution which helps sulfonyl urea herbicides dissolve. When decontaminating after an oily (EC) formulation, the use of a wetting agent such as AgSurf will assist in removing oily residue that may trap SU herbicide on tank and hose material. Commercial tank cleaning products that contain ingredients for removing persistent deposits are available.
Tank and Boom Material
Both plastic and stainless steel are common tank and wet boom materials, and both can be cleaned using the above procedures. However, stainless steel is easier to clean, and this means that less time may be required. Consider the choice of materials a productivity factor in your next purchase or upgrade decision.
Rinsate Disposal
Always spray out the tank in the field. Do not drain the tank while stationary unless you are certain it is free of pesticide and that you are away from sensitive areas and waterways. Consider a continuous rinse system. Consider building a biobed for safe disposal of dilute pesticide waste.
Sprayer cleanout will probably never be the easiest job on the farm. But looking at it in a smarter way can prevent frustration and save time.
May 4, 2026

Sprayer Cleanout and Cleaner Selection

Editor’s Note: Changes have been made to this article since its original publication in 2015.

When in-crop spraying is around the corner, sprayer tank clean out is an important topic to address on your farm. Many farms have done the same clean-out routine for years and not had any issues with contaminating residues in the tank resulting in crop damage. Although the old saying “If it ain’t broke, don’t fix it” definitely has some merit, in this case it is good to question whether your cleanout routine is adequate. When you consider the way chemicals have changed over the years, especially the higher reliance on oily surfactants in modern chemicals, it makes sense why we need to pay attention to spray tank cleanout.

The goal of cleaning the tank is to remove and dilute the previous chemical formulation as much as possible to prevent buildup and carryover of residues which can cause crop damage on non-target crops.

Safety First

Always wear safety gear before working around chemicals. Although it can be a hassle, we all know that it is no fun spilling chemical on your clothes and skin. What’s even worse is smelling it all day in the sprayer cab. I use a long waterproof coat, a plastic face shield to prevent back splash when spiking jugs, and of course rubber gloves (No judgment on me looking like a total dork please:).

1 – Get the Previous Product Out of the Tank ASAP

In my experiences spraying, I have always tried to get the previous product out of the tank as soon as possible. Spraying the extra product out of the tank is the safest and most environmentally responsible way to rid your tank of left over product. Dr. Tom Wolf of AgriMetrix Research and Training, states that spraying a crop twice is usually safe, as all herbicides must be registered to be sprayed at twice the rate in order to be registered by the Pest Management Regulatory Agency (PMRA). If one lets the product sit in the tank overnight before beginning the cleanout, there is more time for product to congeal and adhere to the tank and plumbing components.

I open the valve ends on my filters to empty the buildup in the bottom of the filter canister. There is often chemical residue or green slime from dug-out water in here. Next I like to go along my booms and empty out all the chemical product within the boom plumbing. Our farm runs a Patriot 4420 sprayer, with valves on each boom section to empty out product. Usually I will go to the sprayer and tip the boom ends up so that gravity allows all of the product to drain out. Then I raise the centre rack, and tip end of booms down to force the product to drain out the other way. You would be amazed at how much product comes out by doing this both directions!

Tipping the boom ends up with the centre rack down.

While the tank is empty and no pump is running, I will remove all the filters on the sprayer, and grab the handy dandy toothbrush – this is the most valuable tool in filter cleanout! This brush is just small enough to get it in the centre of the filter and scrub all of the residue and gunk out of the filters. A pail filled with rinsing solution is an easy way to clean filters and nozzles.

Possibly the most important cleaning tool. Don't put it back in the bathroom afterwards. — Possibly the most important cleaning tool. Don’t put it back in the bathroom afterwards.

2 – Begin Rinsing Process

I used to always put about 1,000 gallons of water to our 1,200 gallon tank, thinking that a larger volume would clean all areas of the tank better, but I’ve since changed my thinking. Research has shown that two or three smaller rinses *aka triple rinsing) is more effective for rinsing the tank than one large volume rinse. I always crank the agitation up to high and allow the cleaning solution to agitate for as long as possible.

Nowadays I try to do three 400 gallon rinses.

1st Rinse	Cleaning product plus 400 gallons water
2nd Rinse	Cleaning product plus 400 gallons water
3rd Rinse	400 gallons of just water to rinse, and run through plumbing system to check nozzles and for leaks

Many labels Recommend leaving the rinsing solution in the tank and lines overnight. This will allow more chemical deposits to loosen up. If an operator is forced to speed up the tank cleaning process due to limited time, they must understand that there are risks involved in doing a less thorough tank cleaning.

Cleaning Products

Detergent or ammonia? Check the label. If the label doesn’t specify, you can consult this table from Winfield United.

Detergent Cleaner	Ammonia
Solution contains an adjuvant	Sulfonylureas (SU’s)
Solution contains a milky looking component (an Emulsion or EC)	Thiencarbazone – methyl
Glufonsinate	Flucarbazone
Imi’s (Group 2)	Dicamba
Simplicity

Detergent (e.g. All Clear)

This detergent cleaner is specifically designed to remove pesticide deposits and other debris, including oily substances from booms, filters, and nozzles. Use All Clear (or other detergent cleaner) if the solution is milky-looking (called an emulsion), which means it is oil-based.

Label rate is 0.25 L of All Clear/100 L of water.
If you are adding 400 gal of water, you will only need 3.78 L of cleaning product.
Decontamination rate is double this: 7.57 L of cleaning product. Use this rate if you have had residue issues, or to do a more thorough cleaning.

pH Increaser (aka Ammonia; e.g. Flush)

This is an ammonia based cleaning solution. This product is used to raise the pH to increase solubility of most Group 2 products (from FMC, Bayer, and Corteva but not BASF). Flush contains 7% ammonia. Use Flush (or other ammonia based cleaner) for most cleaning, but especially for Group 2 products listed above, such as Varro, and Velocity M3, Express, Refine, Muster, and Spectrum.

Label Rate is 0.50 L of Flush/100 L of water.
If you are adding 400 gal of water, you will need exactly 7.57 L of cleaning solution.

A pail and detergent are "must-haves" during sprayer cleanup. — A pail and detergent are “must-haves” during sprayer cleanup.

Combo Products

Alternately, some solutions raise pH without ammonia. FS Rinseout is sodium hydroxide based, not ammonia based. It is a high alkaline solution that elevates and holds the pH combined with strong surfactants to help clean the tank. Another is CleanOut, which uses potassium hydroxide and disodium metasilicate, a detergent. In both cases they are both pH increases and detergents.

3 – Draining the Rinse Solution

After I have ensured all nozzles are working correctly, and there are no leaks in the system, I drain out all of the rinse water, fold in the booms, and get ready to fill the tank with chemical solution for spraying!

More Information

Learn where residue can hide. This video was filmed for the Environmental Farm Plan with the nice people at Clean Field Services in Drayton, Ontario. Hardly the height of our acting careers, but good messaging nonetheless.

April 11, 2025

Airblast Spring Start-up and Winterizing
Any description of airblast sprayer start-up must, contextually, make assumptions on how it was winterized for long-term storage. This cyclic relationship is why I use a chicken-and-egg title slide when giving this presentation.
Answer: It was the rooster.
The inability to describe one process without the other is further complicated by the possibility that the sprayer is brand new and was therefore never winterized. So, what follows is an attempt at a logical sequence of pre-season maintenance activities to restore a winterized sprayer, or initiate a new sprayer.
New Equipment
If this is a new sprayer, you have an opportunity to perform some preventative maintenance.
Loosen, lubricate and re-tighten clamps. Always back gears off before tightening to avoid stretching them. (Image from Purdue Extension publication PPP-121: Preparing Spray Equipment for Winter Storage and Spring Startup)
Use double clamps on pressurized lines for added safety. Wider clamps are better and T-bolt clamps are better than worm-gear.
Put thread release on bolts and re-tighten with a torque wrench (not an impact tool). Use a paint pen to mark nut, washer and bolt for future visual checks. This is called a “Witness Mark”.
Protect hoses and wires at rub points. Follow hoses and with a paint pen, number the hose-ends and connections for future reference.
Using a new tractor? You may have to re-calibrate to account for different gear ratios. When hitching a new sprayer, note that the distance from the ball on the drawbar hitch to the tip of the PTO should be ~14″. Don’t exceed maximum working angles for PTO shafts (usually <25 degrees). If your tractor or implement manufacturer says differently, go with that. And get it in writing.
Winterizing (Long-term storage)
If you are preparing the sprayer for long-term storage, follow the normal rinsing process, but don’t reinstall strainers and nozzles.
Look in the nozzle bodies for debris. Discard worn or broken nozzles.
Soak, scrub, rinse and store nozzles and nozzle strainers. You may replace them once the sprayer is clean, but I prefer to store them separately since they have to come back off during start-up.
With the agitation on, circulate undiluted plumbing antifreeze (the sprayer already has 5-10 L (1.25-2.5 gallons) of water in the system from the decontamination process) for five minutes and drain it through the plumbing system (not the booms).
Disconnect hoses where they attach to the booms and drain as much liquid from the sprayer as possible. (Image from Munckhof Sprayers). Take the time to examine any hose fittings.
Clean the sprayer (Triple rinse with a detergent) and scrub the exterior. Do not use pressure washers on bearings, fittings, pumps or any lubricated or moving parts.
Examine fan blades for cracks, build-up or nicks that can cause imbalance. Replace (not just repair) punctured entrance grills.
Don’t ignore tank damage. Poly tanks are prone to sun damage and cracks. Never climb into a tank to repair it. Quite often, replacement is the best option.
Clean and inspect wheel assemblies. It’s best to do this during winterization to prevent bearing corrosion as the sprayer sits all winter.
Remove any rust and repaint (or just touch up). Paint not only looks good, it protects.
The excellent YouTube channel Ask Tractor Mike proposed storing the PTO shaft indoors in two pieces, and to cut away a portion of the interior guard to facilitate reassembly later on. Also, use a paint pen to mark the splines on the shaft for easier hook-up (see inset top-right of image).
RV antifreeze is a 50% solution of antifreeze and water with a rust inhibitor. It should not cause phytotoxicity if sprayed or dumped, but be sure to dispose of it away from water sources during start-up. Turn the pump manually to get antifreeze throughout the system. Close the nozzle bodies, loosely fit the tank lid and store indoors. (Image from Purdue Extension publication PPP-121: Preparing Spray Equipment for Winter Storage and Spring Startup).
Spring Start-up
Most operators are guilty of neglecting their airblast sprayers and babying their tractors. Sprayers are precision tools that must be kept in good operating order to prevent costly breakdowns, improve their performance, and increase their lifespan.
Your car is serviced based on distance travelled. Your sprayer should receive regular maintenance based on working hours, per the manufacturer’s recommendations. Daily sprayer inspections are part of regular maintenance since the operator will (hopefully) find small problems before they become big problems.
Never assume your sprayers is ready to go right out of long-term storage. Parts seize, scale breaks away from surfaces, and small beasties sometimes choose to eat, or make their homes in, cozy sprayers.
When planning spring start-up, never assume the winterized sprayer is ready for immediate hook-up. Expect a minimum half day per sprayer.
Attempting to loosen or shift something that hasn’t moved in several months is risky. Pressure gauges snap off, fittings crack, welds break. Expect the unexpected and either have spare parts on hand, or a plan to get them quickly.
Parts are most likely to seize during the first spray. Bearings and PTO universal joints, especially.
Start-up is a good time to lubricate parts. Grease the guard ring bearing every 100 hours, the universal joint cross every 25 hours and the shaft and shear bolt regularly.
Insects, birds and rodents eat, or make homes in, sprayers. Professional rodent bait/traps, steel wool and peppermint oil/gel are possible solutions.
Check belt tension, alignment and wear. (Image from Purdue Extension publication PPP-121: Preparing Spray Equipment for Winter Storage and Spring Startup).
Pump specific maintenance is beyond the scope of this article. Hypro recommends changing oil after 40 hours of break-in operation and every 500 hours after that. The diaphragms should be replaced every 1,000 hours. Generally speaking, EPDM (black) diaphragms are a better choice for airblast sprayers, while the Desmopan (amber) diaphragms are really for lawn care sprayers.
Pump maintenance is beyond this article, but change the oil every 500 hr or 3 months. Use a paint pen to write on the pump what type of oil it requires, and then date the filters. Note the “winterized” sticker.
At minimum, check the tire pressure. Hard tires drive faster, but leave compacted ruts. Soft tires drive slower, but disperse weight better. Airblast sprayer wheel assemblies should be cleaned and inspected as part of regular annual maintenance. Wheel bearing maintenance before long-term storage may prevent water from corroding the bearings.
Ensure tire pressure matches the ideal stamped on the tire. Or, if using less pressure to avoid spring soil compaction, ensure both tires have the same pressure.
The relief valve on your sprayer should always be in the bypass position during start-up. If your gauge spikes then the gauge may always read high afterwards and should be replaced.
A reminder to always set the relief valve to the bypass position when starting up the sprayer. This is one reason why pressure gauges spike and can eventually fail.
Replacing leaking, opaque or inaccurate gauges improves sprayer performance. Be sure to use the oil-filled variety of gauge to eliminate a bouncing needle. You can also get suppressors that fit between the gauge and sprayer to prevent pulsing. Consult the article on testing airblast pressure gauge reliability.
Use a wrench to turn gauges at the nut. Don’t twist them by hand holding the face. Ensure they are not opaque, leaking, plugged or resting above the zero pin.
Many spray materials do not mix well and one of the common causes of uneven application is poor agitation. If you find deposits at the sump in the bottom of the sprayer after an application, your agitation is insufficient. For mechanical agitators, check for propeller wear and ensure paddles are secure on the agitator shaft. Learn more about agitation here.
If the agitator shaft is leaking a little, tighten the packing. The packing gland is a common source of leaks. Keep it properly greased. If a leak occurs you can usually repair it by tightening the bolts on the packing gland by ½ a turn, but if that doesn’t work you may have to remove and repack (or replace) it.
On sprayers with mechanical agitators, look for prop wear and loose or damaged paddles. Fill the sprayer with water and looks for tank leaks. Tighten the bolts 1/2 turn if the packing gland on the agitator shaft is leaking. You may have to remove and repack the gland if the leak persists.
Look for signs of hose wear and examine the sprayer for leaks while under pressure. Be careful when pressurizing the sprayer for the first time in the spring; this is when lines are likely to come loose or burst. (Image from Purdue Extension publication PPP-121: Preparing Spray Equipment for Winter Storage and Spring Startup).
Minerals chelate (i.e. scale) more readily on stainless steel than plastic tanks. In either case, the first tank of water and leftover antifreeze should be sprayed from the nozzle bodies with no line or nozzle strainers, and no nozzles. Replace them once the tank is sprayed out.
The last step is calibrating the sprayer, and that process really depends on your definition. If the preceding steps conflict with those of the manufacturer’s, always follow the manufacturer’s. Do this for reasons of safety and to preserve any warranty.
Thanks to Fred Whitford (Purdue University), Gail Amos and Mark Ledebuhr (Application Insight LLC) for reviewing the content of this article and for their helpful edits.
March 29, 2025
Clean Your Nozzles
When operators winterize their sprayers, they should remove all the tips and store them separately. Many store them in large pails with lids. Calibrating the sprayer just prior to winterizing will indicate if the nozzles should be stored, or replaced. Let’s assume each tip flow rate is within 5% of the average output and no more than 5% more than the manufacturer’s pressure tables. Yes, industry standard is 10%, but I always wonder how the spray quality suffers with that much wear. Nozzles are, comparatively, a cheap replacement and it’s not worth skimping. Learn more how to check nozzle flow rate, here.
Just like any other part of the sprayer that comes in contact with spray liquid, nozzles (and strainers) should be cleaned regularly. And, just like any other part of the plumbing, the best way to do that is to dilute any residues via a series of rinses. For a more rigorous cleaning, one of the intermediate rinses should include a detergent, and soaking during this step is an excellent practice.
The orifice of any nozzle is delicate, either machined or molded to exacting standards. Even small changes to the orifice shape results in distorted spray (e.g. spray comes out at undesirable angles), a change to the rate (typically more volume per minute) and a change in the spray quality (typically larger median droplet size). If foreign objects or residues remain in the tips, the subsequent spray job may be less accurate and even damage the tips.
In the case of air induction nozzles, which are essentially the standard on most boom sprayers, debris and weed seeds can plug the air-intake ports. When that happens, the nozzle will not function as intended. So, while the occasional soaking of nozzles does a great deal of good, they may also have to be scrubbed. Don’t use picks or reamers! There are nozzle cleaning tools out there, but they’re basically toothbrushes so save your old ones (and mark them clearly). Soft bristles are the way to go for removing stubborn residues and cleaning any tip orifices, but we found a nifty new way:
Occasionally we receive photos like the one below and we’re asked what we think. Well, just the same way we don’t recommend cleaning your sprayer overalls in the family clothes washer, we also don’t recommend the use of dishwashers for nozzles.
Not a great idea. Certainly not if you intend to ever use this dishwasher for anything else. And where does the rinsate go?
In an interesting experiment, Lucas Olenick of Wilger tried cleaning tips in a heated ultrasonic cleaner. We haven’t tested this and we don’t know what heat and vibration might do to poly and ceramic components, but surely it’s no more aggressive than hot, soapy water and a bristle brush. Lucas tried several durations with and without detergent and arrived at this recipe:
“For tough, non-water-soluble pesticides, around 8+ hours in a heated ultra-sonic cleaner with (Dawn) dish soap to come out like brand new. Other solvents may speed this up, but I’d generally suggest against heating solvents at any concentration. For water-soluble pesticides, expect to be within the 3-6+ hours for the first time to be confident enough in not having to flow-test each of the nozzles. With any pesticides, ensure proper care in handling contaminated nozzles and rinsate after cleaning nozzles.”
The mad genius of Lucas Olenick (@WilgerParts) who used dish detergent and a heated sonic cleaner to unplug tips. Be sure to dispose of rinsate safely. Photo credit: Lucas Olenick.
Don’t have a heated sonic cleaner? No problem. Here’s a step by step:
1. Wearing gloves, remove all nozzles, strainers, rubber gaskets and tips from the sprayer.
2. Put them in a large plastic pail and cover them in warm water. Leave them to soak.
3. Drain the pail, but be aware that the rinsate will have pesticide residue.
4. Fill a second pail with a solution of the same commercial detergent used to clean the sprayer.
5. With a toothbrush, scrub the caps, gaskets, strainers and nozzles to remove any residue. Some nozzles can be pulled apart to expose the mixing chamber and facilitate cleaning.
6. Once scrubbed, leave all the parts to soak in the detergent solution.
7. Drain the solution, which will contain trace amounts of pesticide, rinse the parts with water and reassemble the nozzles.
While you’re at it, drop those filters and scrub them alongside the tips. This may seem extreme, but of all the technology on a sprayer, the nozzle has the biggest impact on the effectiveness and efficiency of the spray job. Take the opportunity over the winter months to clean and inspect the tips for damage so the sprayer is ready for calibration in the spring.
Soak, scrub, rinse and store nozzles and nozzle strainers. You may replace them once the sprayer is clean, but I prefer to store then separately. Photo credit: Jason Boersma (@RVFBoys), Ridge Valley Farms, Ontario.
Thanks to Jason Boersma (@RVFBoys), Ridge Valley Farms, Ontario, who sparked this article with his tweet: “Great job for a cold winter day, soak & clean all your tips to be ready for spring also saves on down time!”
September 22, 2022