pH/soil interactions depend heavily on the soil's ability to buffer the chemical reaction.

That said, high pH water will creep your lower pH soil up...but how fast that happens depends a lot on the soil it's applied to.

There isn't a linear answer across the board since it's specific to the soil it's applied to and it's ability to buffer the pH raising/lowering substances being applied to it.

Does this involve the Buffer pH or the Cation Exchange Capacity listed on the soil tests?

For what it's worth, my soil pH was 7.8, buffer pH 7.5, and CEC was 102.6 meq/100g.

Water, no matter its pH will over time wash from your soil the Calcium, Magnesium, or Sulfur that affect the free Hydrogen ions that establish your soils pH. If you have a good, heatlhy soil the pH of your tap water will have little affect on soil pH.

Here is a link that might be useful: About pH

Here in Madison, Wisconsin, the pH of the soil in our blueberry beds rises about one unit per year. However, our shrubs are planted in the ground, not in pots, so I am not able to say if the rise in pH is due to watering, or due to diffusion from the surrounding soil. Our native soil is high in clay, and has pH around 7.6. Our tapwater, supplied by the city, comes from wells that are drilled down into limestone aquifers, and also has pH = 7.6.

It will also depend on the water itself, including the level of hardness minerals AND what they are. The water will have more or less buffer capacity depending on what's in it.

Around here, if you water a pot with tap water long enough, Ca and Mg minerals begin to build up on the surface of the soil. Our water is from limestone and dolomite aquifers so I expect it's ADDING those minerals to the soil rather than leaching them out.

Does this involve the Buffer pH or the Cation Exchange Capacity listed on the soil tests?

Yes. I have been away from the lab too long. I passed the tests at university but don't know if I could have ever explained it to someone else. Wikipedia's Soil pH - Wikipedia, the free encyclopedia seems much improved in the last few years. should you have a keen interest.

In any case, except for extreme circumstances, I would not expect most waters to have much lasting effect upon most soils.

What makes your water's pH so high? We have very hard water (hardness of about 33 grains in the summer). In a low rainfall year, I can see a white crust developing on top of the soil. Because of this, I have ruled out most pH sensitive plants. In the vegetable garden, yearly additions of compost helps the pH some and I try to capture as much soft rain water as possible to help leach the excess minerals.

Our tap water is high in mineral content with Calcium Hardness typically 200-250 ppm. Our water also leaves a white powdery crust when the soil dries out.

Does sulfur take longer to work in soils with higher mineral content?

While I'm thinking about it, does anyone know of a large(r) retailer that sells sulfur in 50-lb bags...and at a reasonable price?

I'm not exactly thrilled about buying sulfur in 4 or 5-lb bags at $3/pound.

absolute -- if you have a local feed store (check the yellow pages) try them. You're looking for "soil sulfur".

An online source in CA (good reliable folks) has it in 50 lbs bags for $27.99 (link below), but at that weight depending on where you are shipping could be more than the cost of the sulfur.

Here is a link that might be useful: Tiger 90 Soil Sulfur

I once bought a 50 pound bag of soil sulfur. I got it from a Garden Center. They didn't keep it on hand but ordered it from their supplier...without a big shipping charge.

Interesting link there TXEB. Sulfur 90% with Bentonite 10% in granular pellet form. I'd prefer this form if it works just as well.

Any experience with this?

None personally. Call the folks at Peaceful Valley - they know their products, are very helpful so long as you know what you want, and are very easy to deal with.

The closest large seller of farm fertilizer is about 50 mi south of here, but I can arrange a stop there on my way to getting pastured meat in the Fall. There used to be one not 15 miles from here but no more. As some of you know, my pH=9.2 water coupled with pH=7.7 soil can be a handful. Only grapes need it in the orchard, and I give it to tomatoes and potatoes in the garden, and of course I add more organic matter than most (21% OM in the garden).

Anyhow, IIRC in late 2011 one 50lb bag of sulfur was $20. I had to sign a declaration that it and the rest of the stuff was intended for food production not to pay the sales tax. If you have relatively large holdings, it pays to go to such a place. A single 50 lbs urea bag allows many years of fertilization between trips.

The 2011 trip was concomitant to starting the orchard in horrible, lifeless, compacted P=7ppm soil, so I got 25lbs of superP, 100 lbs of sulfur, microminerals solution to be added in the sprayer, and 50lbs of urea which will take me to 2020 or so. I have now added over 30 tons of wood chips to the orchard, and the soil is less horrible, but to start it you have to do a first amending.

glib - that's some nasty soil for MI, at least based on my experience. I had some of the nicest sandy loam I've ever seen, on top of glacial till if you went down far enough.

The water I can understand. Question - ever look at the salinity of the water?

Agricultural sulfur is used on fields where alfalfa is grown for feeding farm animals. I suspect it is also used on fields that have seen many seasons of soybean cultivation. I recently purchased a 50 lb bag of 90% S, 10% clay, for $22.50, in Marshall, WI, a few miles east of Madison.