Not every plant absorbs iron well from foliar. A better alternative is to fertilize with chelated iron; it can be absorbed by most everything in spite of the pH. Chelated minerals are a little pricey; but for me (Meyer Lemon grower), they are sorta like an insurance policy.

Because a one-time application of sulfur usually solves the problem- particularly if it's incorporated or at least placed under mulch.

"Because a one-time application of sulfur usually solves the problem- particularly if it's incorporated or at least placed under mulch".

Harvestman,

No......not even close. That is like saying adding ice to your drink and leaving it on the counter will keep that drink cold forever. Does not work that way. The soil always will revert back to the native soil PH in time just the same as the water in your drink will return to room temperature. If you are irrigating the plants with water that is rich in bicarbonates or any bicarbonates it just speeds up the process. It may take months or a year but that PH will rise. The real problem is the delay from when you add the sulfer until it kicks in but in any case you will have to add sulfer much more than "one time".

During a recent e-mail conversation that I had with Keith at Backyard Berry Plants, he mentioned an experiment that he'll be running next year that, similarly, challenges assumptions about blueberry bushes and soil pH in container culture. His theory is that, for potted plants, "liquid feeding supplies nutrients to the blueberry irregardless of soil pH. To test this," he continues, "I'll have our mix we use as a control, and then some mixes that are buffered to varying pH's, including an alkaline pH (8.0)." While this doesn't go quite as far as your suggestion, gonebananas, it's definitely in the same vein -- as long as you can supply the necessary nutrients in a way that's accessible to the plant, soil pH isn't particularly important. I recall that Al (tapla) has suggested something similar (i.e. that media pH is less important for container blueberry culture than the pH of the nutrient solution). I don't think he goes so far as to suggest ignoring pH, of course, just that his 5-1-1 mix (without lime) should be close enough to a proper pH that it's not really worth monitoring the media pH all that carefully.

Bamboo, I meant compared to frequent foliar applications. I realize the pH always reverts after amending over time. The usual schedule here is once every four years- at least for liming. I've found acidifying here longer lasting, but that's probably because we tend to run slightly acid to begin with.

Thanks for explaining....could not for the life of me figure out how you could think that.

I do sometimes use the chelated iron but as a foliar spray, figuring that portion washed off becomes regular root fertilizer eventually.

If you don't mind the effort required to correct soil and/or irrigation problems the micro sprays are an ok and last option, that said; when it comes to certain situations, like mine, correcting the soil problem has distintct advantages. 1) when it comes to micros in my calcareous soil, Mn, Zn, Cu and Fe are all tied up by the bicarbonates, therefore, they can all be deficient in the plants, dumping my irrigation water (also high in bicarbonates) with no treatment onto the soil exacerbates the problem. Needless to say, trying to account for those 4 deficiencies by foliar sprays would be a challenge. As you all may know, sometimes it can be difficult to impossible to get a spray on when it is needed due to life or the weather, I usually have the time for S applications and am already irrigating so it's no real extra time to treat the water and I don't have to spray something else, whoopee! Yes I realize things like chelated Fe can be tank mixed with other things thereby avoiding an extra, separate spray.
Anyway, I just prefer to fix the problem in the soil and water to......that's my 2 cents worth.