I don’t know if you have purchased a new sprayer lately, but even ATV-type spot sprayers have gone up a good bit in price. What else is new, right? Everything is more expensive, but that makes it more important than ever to properly protect and store our spraying equipment.

Overbay andy
Extension Agent | Virginia Cooperative Extension
Andy Overbay holds a Ph.D. in ag education and has more than 40 years of hands-on dairy and farmi...

Complicating the winterization of our spraying equipment is that some of our farm’s target pests are best controlled in the cooler months, when they are in the proper stages of growth.

While we may want to use our sprayers during these cool times, like most everything on the farm, there are no timeouts. Once a cold snap has damaged our sprayer pump, filters or other components, it’s too late to worry about winterization.

The best additive to protect our sprayers is an RV-type antifreeze. It is safer to both humans and pets, and it’s safer for the environment when we flush it out next spring. Never use automotive-type antifreeze. The risk of accidental poisoning is just too great.

The first step to getting your sprayer ready for cold weather is to get it as cleaned out as possible. We want to make sure there are no chemicals in the sprayer that could be an issue on down the road.


If you are a tightwad like me, you might be tempted to try to salvage the tank mix that is left in the sprayer. Do not attempt this, mainly because it is likely a waste of time and could result in a failure from a pest control standpoint later. Chemicals tend to separate over time, and once the ingredients of your tank mix fall out of solution and crystallize, the chances they will remix correctly are slim to none.

We also don’t want to just run any mix out on the ground. Our best bet is to apply the mix to a target that the spray will control and do so at a diluted rate. Remember: Dilution is the solution to pollution. This is a good time to also consider the issues with buying only the amount of chemicals we need for any given season and also only mixing the amount of spray solution we need to cover the targeted area – and that area only.

If you do have spray concentrates left over, you will definitely want to check their labels to see what they require for off-season storage. As we in the business will tend to preach, “the label is the law,” so please take the time to familiarize yourself with both proper and legal storage of chemicals – especially restricted-use chemicals.

Keep chemicals in their original containers and check for possible leaks or package damage before storing them. This is especially important if you need to bring your chemicals inside your home (such as storing chemicals in your basement) during the cold-weather months.

Once we have the tank (or tanks) cleaned out, we can add our RV antifreeze to the sprayer and (using the agitation mode) run the antifreeze through the main pump. Your owner’s manual should give you instructions on the amount of antifreeze you will need to properly treat your spray rig, but if you do not have your manual, you can likely find the proper amount with an internet search using your sprayer make and model.

One area to pay close attention to is the filter (or filters) on your sprayer. These are mostly screens of different gauges that can become clogged over time with chemical slimes and debris from past mixes. Chemical reactions to additives that neutralize and bind up chemicals in tank mixes can exacerbate this issue, and the clogged filter may not receive proper protection against the cold.

As with the filter, once you have run the antifreeze solution through the pump in agitation, you need to push the solution through every component in the system. Work the solution through your handheld spray gun and through the nozzles if applicable.

Boomless nozzles are fairly simple; however, if your spray rig has a boom, you need to make sure they passed through every nozzle. If you rig is equipped with multiple nozzle tips, I would suggest rotating them to make sure no water finds its way into the inactive spray tips.

RV antifreeze tends to foam as it hits the ground, so if you are winterizing your spray rig yourself and are monitoring nozzle output from the operator’s seat on a large sprayer, you should be able to visually see that antifreeze is being passed through the system.

The same can be said for any valves your spray rig may have. Rotate valves on and off to ensure no water has found its way into the valve, causing it to split and fail in the cold weather ahead.

Like any part of our farming operations, if we want our machinery and equipment to take care of us, we need to take care of them. Proper maintenance takes time, and time is one thing we cannot manufacture, so it is best to use time wisely.

Believe me when I say this, “Experience is not the best teacher.” The best way to find out that your spray rig has suffered cold weather-related damage is not by watching tank mixtures pour out through holes and cracks in failed components next spring. Treat your sprayer so it will be ready to attack targeted pests next spring.  

Andy Overbay holds a Ph.D. in ag education and has more than 40 years of hands-on dairy and farming experience.