Kniles:

I rinse my sprayer out with the hose occasionally, but there is not much reason to be concerned when switching between different insecticides and fungicides. Most of these chemicals are compatible, and are often applied in combination anyway. An exception is oil and lime/sulfur. If a heavy concentration of dried material, such as copper, builds up at the bottom, I take a rough sponge and warm water and reach in to scrub it out. What kind of chemicals are you using that are causing you concern?

If you are alternating between insecticides and herbicides, using the same sprayer, that is something you should not do. One of the first rules of spraying is to designate separate sprayers for herbicides and insecticides/fungicides.

If you are ending up with spray material in your tank when you have finished spraying, you simply need to mix up less. I must say, that is quite an unusual question.

Don Yellman, Great Falls, VA

Kniles & Don-
I agree. It's an unusual question. But one I've thought of posting myself.

I want to have enough spray (of any given spray) to do all the trees I intend to do. I don't want to have to come back and mix up a quarter batch, or something like that. So, I often wind up with a bit extra in the tank. In the past, it was the cruddy all-in-one spray or the dormant oil or the stinky deer spray or..

IÂd prefer not to send it down the drain into my septic and, IÂd have to bring it inside to find a drain, which I donÂt want to do. I'd prefer not to toss it in the stone driveway, as I have a well thatÂs not too far from there. This year, IÂll be spraying Kocide 3000 copper, and IÂd prefer not to overspray the rest onto the trees due to copper buildup in the soil. IÂve tried diluting it as best I can, and then tossing it on the grass, but the grass didnÂt seem happy with it. One time, after diluting it to the fullest extent I could, I took it for a long walk in the woods.

Another example is that I may spray dormant oil, and then a little while later, the fruit tree spray which contains Captan (need to get rid of the fruit tree spray, and it handles my Plum Curculio issues). Normally, on a tree, Captan too soon after oil can cause phototoxicity. If you didnÂt clean out the sprayer between those two sprays, could you have a problem? I wonder about these things, but I realize, I really need to get a life.

Yep, my herbicide sprayer is a 3 gallon black one. My 4 fungicide/insecticide ones are yellow.

For me, what IÂve done is have 4 one-gallon hand sprayers lying around. (It helps that the in-laws own a hardware store!) . Whatever I donÂt use, just sits around until next time. And, then I add to it. But, IÂm not sure how well the spray does when itÂs been already mixed up and sitting in a warm garage or shed.

As of 2 hours ago, I ordered by Solo 3-gallon diaphragm backpack sprayers per DonÂs recommendation. At the price of it, though, I certainly wonÂt be getting for of Âem!

-Glenn

I flush out the sprayer after every use - fill with some water and spray until it comes out clear. Someplace or someone told me that was the way to do it. I never do any other cleaning except when it gets clogged. I always empty the sprayer, never leaving extra. If I have a bit left I give that last row one more go-over, or maybe the tomatoes wouldn't mind some copper or the persimmons could use some summer oil... I think early on I dumped some things but now I have a pretty good measure of what needs how much. Some things can keep in the sprayer but other things lose effectiveness rapidly.

Scott

To clean your sprayer, after using up all the spray, the general recommendation is to triple rinse. Do this by filling it at least 1/2 full of water, swishing and shaking it around with the lid on, then dump the water out and repeat. After the third rinse has been dumped, there is so little remaining pesticide in the tank that it won't be of concern. However, if you are still using the tank for both herbicides and insecticides, DON'T. You can also increase the cleaning and neutralize any remaining pesticide by including a tablespoon or two of washing soda with the rinse water. This works particularly well when trying to rinse herbicides out of a sprayer.

Extra spray can still be effective if you don't save it more than a few days to a week, though it depends on the chemical. Pesticides that degrade in water with a high pH won't last too long if you use alkaline water. Things like your copper probably will still be good if stored until next year. If I have insecticide that I don't use, I will sometimes leave it in the tank until the next time I spray, then fill the tank and mix fresh chemical at the low rate on the label and use it that way. Extra chemical can also be poured into an empty 2 1/2 gallon jug and stored, and if you don't want to use it, you can probably add a tablespoon or two of washing soda to help denature it, then after a few days pour it out over a very wide area so you don't have the potential to build a concentration of any remaining chemical in one place, or just send it to the landfill.

I have found that when using surfactants, they often don't store well in a mixture and will tend to form a slime that plugs your screens and small orifices. Those are best used as soon as mixed and if you have some extra chemical, spray around your foundation, offer to spray the neighbor's trees, etc. and just don't mix as much the next time.

I have a John Bean sprayer with a 25 gallon tank on my tractor driven by the power take off. I learned the hard way to clean thoroughly after each use. Installing a new valve kit in a Bean sprayer is to be avoided. I am careful to mix the amount I need only and always use it all. Excess copper that gets in the runoff and into the streams or lakes is deadly to marine life. Al

As always, thanks guys.

I never keep spray that I don't use. Most of the time it will either go bad or clog your sprayer. I'd much rather mix not enough spray, and remix, if I run out.
I clean my Rocket Sprayer by dumping out the unused spray, then rinsing out the sprayer with clean water, then I
refill the tank and put several drops of Dawn detergent
in the sprayer, activate the sprayer and spray out at
least half the tank. This cleans out the spray hose and wand.

I always rinse my sprayer. I don't like to deal with clogs so I'd prefer to take the time to rinse it after I use it. Any extra spray gets dumped on the lawn in a spot where I don't care what the grass looks like. I'm getting better at mixing just enough for what I'm doing though. The only spray that I'll keep is my Round-up since that doesn't really go bad, but fungicides and lime-sulfur do go bad so they get cleaned out right away.