7 Ag Sprayer Maintenance Checklists Old Farmers Swear By

There’s no worse feeling than being halfway through a critical spray application when a nozzle clogs, a hose bursts, or the pressure drops to nothing. Suddenly, your perfect window for pest or weed control is closing fast, and you’re stuck troubleshooting a machine full of expensive chemicals. This isn’t just an inconvenience; it’s a potential crop-saver turning into a money pit, all because of a preventable failure.

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Why a Sprayer Checklist Saves Time and Money

A sprayer isn’t just a tank on wheels; it’s a precision application tool. When it fails, the costs add up faster than you can walk back to the barn. First, there’s the wasted chemical, which is never cheap. Then there’s the potential for crop damage, either from the untreated pest or from an uneven application that burns your plants.

Think of these checklists as insurance. Spending ten minutes on a walk-around before you start can save you a three-hour repair job in the middle of the field. It’s the difference between a smooth, effective job and a frustrating, costly disaster. A well-maintained sprayer applies the right amount of product exactly where you want it, saving you money on inputs and protecting your yield. It’s that simple.

The Annual Pre-Season Sprayer Shakedown

Before you even think about putting chemicals in the tank for the first time each year, the sprayer needs a thorough shakedown. Winter is tough on equipment, causing plastic to become brittle and rubber to crack. This is the time to go over every inch of the machine, looking for problems that developed during storage.

Start with the basics. Check all hoses for cracking, soft spots, or brittleness—squeeze them to be sure. Inspect the tank for any cracks, especially around fittings. Look at the pump and check the oil if it’s a diaphragm or piston pump. Manually turn the pump over to make sure it isn’t seized.

This is also the perfect time to clean or replace all your filters and strainers before they have a chance to cause a problem. Fill the tank with clean water and run the pump. Check for leaks at every connection point, test the pressure regulator, and make sure all the boom sections turn on and off correctly. Finding a leaky fitting now is a minor annoyance; finding it with a full tank of fungicide is a major headache.

Daily Walk-Around: Before You Fill the Tank

Your daily check is a quick but vital habit. It takes less than five minutes and catches 90% of the problems that will stop you in your tracks. Before any water or chemical goes in, do a simple walk-around. Look for the obvious stuff first.

• Tires: Are they properly inflated? A low tire can throw off your boom height and application rate.
• Hitch and PTO: Is the sprayer securely hitched? Is the PTO shaft properly connected and shielded?
• Visual Leak Check: Look under the sprayer for any fresh drips that weren’t there yesterday. Check the pump, valves, and hose connections.
• Tank Lid: Is the seal on the tank lid in good shape? A poor seal can cause splashing and pressure issues.

This isn’t about rebuilding the machine every morning. It’s about catching a loose hose clamp or a dripping valve before you fill a 50-gallon tank. It’s a simple discipline that prevents messes, saves chemical, and keeps you safe.

Post-Spray Triple Rinse and Flush Protocol

Cleaning the sprayer immediately after use is non-negotiable. Leaving chemical residue in the tank, lines, or nozzles is a recipe for disaster. It can damage the sprayer components, cause cross-contamination that harms your next crop, and lead to stubborn clogs that are a nightmare to clear.

The triple rinse is the gold standard for a reason. First, drain the tank completely in the field you just sprayed. Add clean water to about 10-20% of the tank’s capacity, along with a tank cleaning agent if needed, and spray it out through the booms. Repeat this process two more times. This systematically dilutes the remaining chemical residue to insignificant levels.

Don’t forget the "dead ends" in the plumbing. After the final rinse, take the nozzle caps and strainers off and give them a separate cleaning with a soft brush and water. Store them off the sprayer if you won’t be using it again soon. A clean sprayer is a reliable sprayer, and it ensures you don’t accidentally apply a broadleaf herbicide to your sensitive vegetable patch.

Weekly Nozzle, Strainer, and Filter Check

Your nozzles are the most critical part of the sprayer for accurate application. Even a small amount of wear or a minor clog can dramatically alter the spray pattern and output. A weekly check, or more often if you’re spraying wettable powders, is essential for keeping things consistent.

Use a soft brush (an old toothbrush works great) and a bucket of water to clean every nozzle tip and strainer. Never use a wire or a pocketknife to clear a clog, as you’ll damage the precision orifice and ruin the spray pattern. While you have them off, inspect the tips for visible wear or damage.

Don’t stop at the nozzles. Your sprayer has other filters designed to protect the pump and prevent nozzle clogs. Check the main suction filter and any in-line filters in the boom sections. A dirty filter restricts flow, puts a strain on your pump, and is the number one cause of pressure problems.

Monthly Pump, Hose, and Agitator Inspection

Once a month during the busy season, it pays to do a slightly deeper dive into the heart of the system. Your pump, hoses, and agitation system work hard, and they deserve a closer look. This check is about catching wear and tear before it leads to a total failure.

Start the sprayer with water and just listen. Does the pump sound different? A new knocking or whining sound can indicate a problem with a diaphragm or bearing. Check the pump’s oil level and clarity. If it’s milky, you likely have a bad seal and water is getting into the crankcase.

Next, with the system pressurized, carefully inspect all the hoses. Look for bulges, soft spots, or signs of abrasion where a hose might be rubbing against the frame. A bulging hose is a blowout waiting to happen. Finally, look inside the tank while the agitator is running. Is it creating a good swirl? A weak agitation leads to poor mixing and uneven application, especially with powders.

End-of-Season Winterization and Storage Prep

How you put your sprayer away in the fall determines how easily it starts up in the spring. Freeze damage is the ultimate enemy of a sprayer. Water left in the pump, valves, or boom lines will expand when it freezes, cracking housings and destroying seals.

The process is straightforward but must be thorough. After a final, deep clean, drain the entire system as completely as possible. Open all valves and remove all drain plugs. Then, add a few gallons of RV antifreeze to the tank.

Start the pump and run the antifreeze through the entire system—the pump, the valves, and out through every nozzle on the boom until you see the pink fluid. This ensures every part of the system is protected. Store the sprayer inside if possible, or at least under a cover, to protect hoses and plastic components from UV degradation. Proper winterization is the single best thing you can do to guarantee a trouble-free start next season.

The Critical Spray Pattern and Calibration Test

All the maintenance in the world doesn’t matter if the sprayer isn’t applying product correctly. A pattern and calibration test is your final exam, and you should do it at the start of the season and any time you change nozzles or application pressure. It tells you if your application is uniform and if you’re putting on the right amount.

For the pattern test, simply fill the tank with water and spray onto a dry patch of concrete or a gravel driveway. The wetted pattern should dry evenly. Dark streaks mean too much overlap or worn nozzles, while dry spots indicate a clog or a bad nozzle. It’s a simple visual check that immediately reveals problems.

Calibration sounds intimidating, but it doesn’t have to be. The goal is to confirm your gallons-per-acre output. There are many simple methods, but they all involve catching the output from a nozzle for a set amount of time and combining that with your ground speed and nozzle spacing. An uncalibrated sprayer is just guessing, and guessing is a good way to waste money or damage your crops. Taking 30 minutes to calibrate is one of the highest-return activities you can do on the farm.

These checklists aren’t about adding more chores to your already long list. They are a system for turning sprayer maintenance into a simple, predictable routine. By building these habits, you transform your sprayer from a potential liability into one of your most reliable and effective tools.