There must be something you can add to get that ph down.
It would probably take very little to bring it down.

My worst experience was glyfosate in alkaline water.
I sprayed out half a tank then some one turned up and I left the mixture sit in the tank for a while.
You could clearly see where I had stopped and restarted.
Glyfosate is a weak acid and the lime in my water ruined it .
I wonder if there is something that they use in swimming pools that would be available

Buffering agents commonly contain phosphates as the acidifying agent. Vinegar is not considered effective in buffering the water and protecting the pesticide. Relatively small amounts of a buffer will do the job. There are numerous buffers available, one of them is pHase5 (there may be others) contains a pH sensitive dye which will color as the pH changes, so you don't have to make measurements, just add and mix until the color indicates the desired pH. You will probably have to at least look them up on the internet, then find the quantities available. Getting a 2.5 gallon jug, commonly used in agricultural operations, will last a homeowner the rest of their lives and then some. Just look up "buffer spray adjuvant" and read a few university sites to get the background and find some trade names.

I've never used a buffer although my water runs 7.8 to over 8 in pH, however I often add a little ammonium sulphate. I think this will acidify the water to at least some degree--at least its chemical makeup says it should. Used to be that the Roundup label recommended adding ammonium sulphate or liquid nitrogen and a surfactant to improve effectiveness. The labels don't say it is needed anymore and dealers claim that Roundup contains the adjuvants premixed. However, I still see much better activity from the Roundup (and generic glyphosates) if I still add the adjuvants. Consequently, I will add a little ammonium sulphate anytime I am spraying a pesticide that is pH sensitive.

Thanks Bee on the tip about pHase 1. Never heard of it but I'll be ordering some for next season. I was planning to buy a water pH tester or at least use the paper but you've given me another option.

Citric acid is also another option. That's what most commercial growers use. It's cheap, readily available, and recommended by university extensions. As noted, it does require a pH tester to test the pH, but if your fresh water runs a consistent pH, then once you figure out how much citric acid to use, you won't need to test the pH every time you mix spray. Citric acid takes a VERY small amount to adjust the pH. My water has a whopping 9.4 pH and only takes about 1/12 teaspoon/gal. to bring the pH down to 6. Mineral acids are not recommended to adjust pH.

Michael, actually, you have it backwards on copper. Copper should never be acidified. For anyone looking for a very small quantity of citric acid, look in the canning section of your grocery store. One reason for incompatibility in certain sprays is that one spray requires, or makes the solution alkaline, and another spray (most sprays) require acid.

Yeah, the only thing that makes pHase 1 attractive to me is that my business in Spring is "has 25 gallon sprayer- will travel". Because I use a small sprayer I can whip up small custom batches for most any need. The drawback is I may use 5 or 6 different water sources on any given day.

Because the soil around here tends to be mildly acidic I never used to worry about pH even when using Imidan, which needs acid water. Figured the well water would reflect the pH of the soil.

I had already been spraying a couple years before I became aware of the issue and never seemed to have suffered for my ignorance in spite of many applications with water from many wells. All I spray is orchards, so this meant most applications included Imidan, sometimes where it sat in the tank for some time.

I live in an area where unprotected apples, etc, haven't much chance most seasons so I guess I was lucky.

Al,

Even though you live in the acid side of the country, you may want to take a look at this link. Apparently most of the rivers are alkaline, even those back east. Says the Potomac is 7.8-8.4. Same article says half-life of Imidan is 4 hours at 8.3. You may be getting good control because of the high toxicity of phosmet on moths. Don't forget, the pesticide continues to degrade until it's dry on the leaves. Of course this research is from Cornell, so take it with a grain of salt :-)

Here is a link that might be useful: Pesticide stability

Olpea: Wow 9.4! Will a spoon stand up in a glass of your water? I presume that is predominately Ca. I was trying to convey that there are pesticides that don't do well in alkaline water and that Kocide 2000's label states in the Special Precautions section that pH must not be allowed to go below 6.5 to avoid pH related phytotoxicity. That was easy, wonder why I didn't just say that the first time.

Viral encephalitis wracked my brain a few years ago and I make a few more mistakes more than I used to. So, thank you for pointing out an important one.

Here is a link that might be useful: Kocide 2000 label

Michael,

Naw, not calcium, sodium. Our nutty water district packs the water with soda ash to get the pH up. When I first read the pH was 9.4 in their report, I couldn't believe it. I checked with a meter, and sure enough it's 9.4. Strangely, our water district won some contest for the best tasting water in KS. All that sodium tastes goooood.
Mark

I don't get my water from the rivers, but from wells, my customers are very rarely on town water. However, I will no longer risk the highest possible efficacy of my sprays and will test all future water well by well. The point I was making, if there was any point at all, was that I feel lucky to have had good success in spite of inadequate pH monitoring. This success was primarily about controlling Plum Curculio.

Olpea: SODIUM!!! Have you developed any water infiltration problems in your soil? I seem to recall that sodium causes clay soils to defloculate as the calcium is displaced by sodium and those nice soil particles with soil pores between them are destroyed. I hope that doesn't happen to you. What water district is yours, Ours is Jewell Co, RWD #1.

You can always pour a little dish washing soap into the tank. I know people who use to throw a handful of Tide into 400 gallon tanks. Not scientific, and lots of suds, but better than nothing.

Michael,

Sodium may destroy internal soil drainage, but I'd think it would be hard for the sodium to displace calcium. Na has a +1 charge while Ca has a +2 charge. Once, someone who did soil consultation work told me that he'd removed Na on sodic soils, by adding Ca to the soil. With it's stronger +2 charge, it displaced the bound up Na and the Na was washed out of the root zone with heavy irrigation.

Either way, I've quit irrigating with our water. Our problem is more too much water. Water table's pretty high. What town you located near? I'm in the Stilwell/Bucyrus area.

A handful of Tide in a big tank, or any soap for that matter, works as a surfactant, not as a buffer. As a surfactant, it helps the spray evenly coat the leaves and helps cut through the waxy surface of the leaves to allow the pesticide to penetrate into the plant better.

A good example of this effect is spraying insecticide on cabbage plants. With just water and insecticide, when you spray the leaves tend to remain exactly the same color and most of the spray beads up on the leaves or runs off--looks like dry leaves with droplets on them. Add a little soap (surfactant) and spray, and the leaves will color a darker green and look wet with no droplets visible.

Oldpea--the sodium may not displace the calcium if you have plenty, but it is still salting the soil down. Unless you have a clean water source to flush the sodium out, over time your salt levels may build to the point of being damaging. Why in the world would a water system add sodium to the water? Do they also add lead or arsenic to get that "mineral" flavor? Just kidding--I think. I'd use well water or something else to protect the soil.

yes the Tide was what we call a spreader. I don't know if there was any buffering action at all. I don't know what my supplier will have this year in the way of a buffer, but in the past a pint per 400 gallon tank was enough to buffer it from about 7.8 to 6. These products are sold by the gallon and are not expensive. People should be able to buy them at the larger ag supply houses and you can see that a little will go along way.

olpea: I'm in the Mankato area. Good point about the divalent vs monovalent elements and their relative attraction to soil. I recall from my school days that sodic and/or saline sodic soils are reclaimed by chucking on the Ca and then leaching away the Na with heavy irrigation. What I'm not 100% certain of is whether added Na can displace Ca in soils, back to my soils texts I guess.