Excellent... thank you, SO. I think chemistry was my worst subject in high school, so having you summarize that simply and plainly is much appreciated! No danger of getting our soils anywhere near 6, eh? lol We must have excellent buffering qualities (hope I'm using that term correctly), though, because the efforts to lower pH here seem to be sticking better than areas such as daninthedirt is speaking of (great username, by the way, Dan). I also have a rather easy time lowering water pH for our aquarium fish; half distilled and half dechlorinated tap water keeps it in a comfortable range for them without having to purchase adjusting chemicals. (We're now on the river water pipeline that goes into town; well water was much, much worse and I could only use a small amount mixed with the distilled.) We're rural in the Humboldt area, but we have family who is mixed farming the Young/Allan area. :) Prairie Garden Seeds is in Humboldt here and I met Jim and his family briefly when I picked up a seed order last year. Nice folks. I should ask for a tour of the seed gardens someday. One more question. Our garden has flooded before. How long does it take for the iron to then get back to an unavailable state after such an incident? So as not to hijack crabbygardener's thread any further (sorry about that), I'm going to spin off with a new post over in the soil forum regarding my question about zinc and copper. This post was edited by macky77 on Sun, Mar 16, 14 at 11:29

It helps to know something of the natural history of your area. For example, our soil, here in Madison, Wisconsin, was once a seabed, during a long period when much of North America was covered by saltwater. We have two layers of limestone, formed from the leftover seashells and diatoms that sank to the bottom when the creatures died. Our native soil has a pH around 7.6, and our garden is healthy and productive, with only compost added to help loosen up the clay. Our compost starts out with shredded maple tree leaves, and there is also yard waste added, but not very much nitrogen source. I suspect that there are thousands, if not tens of thousands of folks in the midwest gardening successfully in soil similar to ours. However, we also grow blueberries, and we are using agricultural sulfur to lower soil pH, down to the range: 4.5 - 6.5, essential for blueberry success. Its not that hard to lower soil pH, but you will need to learn how to measure soil pH, so you know where the soil is at, before and after applications of sulfur.

Thanks to everyone for the interesting responses. dirtydan, have you had a soil test done to determine why your pH is so high? Unfortunately there is no one in this area that will do a soil test for less than $70 per sample. I recently found a link to University of Mass Amherst that offers soil tests for $13 so I am planning to send them some samples. http://www.umass.edu/plsoils/soiltest/soilbrochure2009.pdf I use home test kits for nutrient and pH. I also have a Hanna pH meter that comes in handy for quick tests. I don't know my native soil composition. Its pretty bad though. It could be described as dense gray clay with some occasional small pockets of white material. When dry, its is normally cracked and coated with a layer of frosty looking crystals that taste like salt. The salty crystals grow up the side of masonry, concrete and stucco walls. When wet, it turns to a slippery slime that will coat the bottom of your boots with a couple pounds of thick clay. It has no vegetative matter whatsoever. I have been prepping my raised beds with compost, sand, clay, fertilizer and various sulfur products to lower pH. Where are you in the Mojave? I am located in the city of Lancaster, CA. This is the high desert north of Los Angeles at about 2,400 ft elevation. We only get about 5 inches of rain per year, most of it is in February. In fact we will probably not see any significant rain here until next fall or winter. The arid conditions are one of the reasons for the high soil pH and lack of organic mater, also the fact that we are almost entirely dependent on alkaline municipal water for irrigation. What are you trying to grow that is having trouble? When I first moved here I put tomatoes, squash, cucumber, melon, and several others in the unamended native soil. They were all killed or stunted from the salt or nutrient deficiencies. Iron chlorosis and micronutrient deficiencies were evident in the plants that didn't die immediately. The only exception were some tomatoes that I managed to save by side dressing with aluminum sulfate and a highly acidified nutrient solution, they remained quite stunted however and suffered from BER. Since I have built raised beds and worked the soil, I have a productive garden and only seem to have problems with cucurbits in beds that have been freshly sulfured, and typical aphid and leaf miner infestations. There are two main reasons as to why sulfur is the preferred material for acidifying soil. 1. Economics Sulfur is one of the most plentiful and inexpensive elements on earth, said to comprise 2% of the mass of the earth. Sulfur is a byproduct of oil and gas refining and there is a massive oversupply of the material, especially in Canada where its is extracted from oil sands during refining. High concentrations are not toxic to vegetables. Cucurbits being the exception. Avoid sulfur contact with the leaf surface of cucurbits. Other possible acidifying agents (some impractical): ammonium nitrate liquid nitrogen urea diammonium phosphate acetic acid hydrochloric acid HCl (also called muriatic acid) phosphoric acid Elemental sulfur has been used for centuries as a fungicide and miticide. I don't know if, or to what extent, it affects beneficial soil fungi. I suppose that a reduction in soil fungi is OK as long as our vegetables are not negatively impacted, and there is no damage to the environment. Once the sulfur it oxidized by soil bacteria I would speculate that soil fungi will return to pre-application population size.

Phosphoric acid, nitric (muriatic) acid, sulfuric acid or citric acid are used to lower pH of water. Vinegar is too weak because high pH water is buffered by minerals. Food Grade Phosphoric Acid is used in commercial greenhouse operations. Although no acid is "safe" and all must be handled with care, nitric and sulphuric acid are dangerous. Citric is expensive. Food Grade Phosphoric Acid adds phosphorus, ppm, to the water. If the water is very hard or a person is using triple phosphate fertilizers then care must be taken not to exceed the plant limits. Water hardness and pH are related but not the same. pH is a measure of the acid or base. Hardness is a measure of the buffering ability of the dissolved minerals in the water. The type and quantity of dissolved minerals in some water requires more acid to lower the pH than water that might have a different mineral composition. The people over at the hydroponic forum can be very helpful for specific questions about water pH, raising and lowering. This post was edited by lucky123 on Thu, Aug 21, 14 at 0:11