Egads. Too much of a good thing, fruitnut. I'm going outside right now to check MY blueberries. I amended the soil with soil sulphur, and we just had about an inch of rain last night and today. I'd be sick if I overdid it with the soil sulphur. Especially since I rescued two of my blueberries from rats (well-caged, now.)

Patty S.

Patty:

It's true the same could be done by adding too much sulfur. Since few people get the testing needed to figure sulfur application accurately, an over application is easy.

I am happy to know that excessively low pH can be so easily raised using alkaline well water. The first time I grew potted BB, the soil test said my pH was too low. I don't think it was but I was adding limestone to my pots. Limestone takes months to years to be effective. Alkaline water hours.

So far one friend has had pH 2-3 and another 6. Neither is working very well. My new Accurate 8 pH meter makes it all easy from now on around here.

Fruitnut,

I did a search on the Accurate 8 pH Meter and it looks interesting. The site I checked out had it for sale for $70.00 That hopefully should take it out of the "Junk" catagory. I couldn't find any product reviews so you are the man.

Have you done any accuracy tests yet to verify how good it really is? Are there any tricks to cleaning the probes between checks? Have you found any limitations to it use or effectiveness? Does the unit's probe actually give different readings at different soil depths?

Do you feel that the moisture meter function also works well?

The risk of too much sulfur can be reduced somewhat by using granulated or flaked agricultural sulfur, instead of powdered horticultural sulfur. An application of agricultural sulfur will take 12 months, or maybe 18 months, to be fully metabolized by soil bacteria, so the pH will be dropping slowly over that time frame, and this gives the gardener more time to react. The down side, of course, is that you have to wait 18 months for the pH to drop all the way to where you want it.

northernmn:

I haven't done any accuracy testing because I don't have anything accurate. But I continue to be happy with the unit. All readings appear reasonable and they are repeatable. My buddy is getting the same meter so when it arrives we can see if the readings match.

The moisture function appears to be of questionable value at best. It reads wet on everything I stick it in probably because it is in fact pretty wet.

I do get different readings at different depths to some extent. But there is no way to tell if that is real.

I hope to have more to post soon.

Why not just pour out all the soil, rinse the pots and roots, refill the pots with pure peat or a mix of mostly peat and potting soil and put the plants back? Problem solved.

RM

RM:

You don't just pour out the soil and rinse the roots. Blueberries form a solid mat of rootball. After a few years the rootball gets so dense it's hard to get the probe in the soil. You can cut the rootball down in size and repot. But I don't see separating soil from roots, not on a plant with any size or age.

The pH of the original subject of this post has stayed in the 4.5 to 5 range after leaching with well water. I think this is the ideal way to raise pH of potted blueberries that have drifted too low in pH. I had a few more that had drifted to the 3.5 range. One rinsing with well water and they are back to an average of 5.

I don't know of another way to raise pH a point or two in a matter of hours or less.

Good to know the outcome for the blueberries was successful, and this is exactly what our extension folks say for blueberries in pots out here in Calif, too - if you get them too acidic, flood the pot with water until you can get the pH back up above 4. Just had the chance to listen to Ramiro E. Lobo, who is the UCC E Farm Advisor, Small Farms & Agricultural Economics for San Diego county, and is our "blueberry expert" in the state of California. He spoke at our March CRFG meeting, and also presented at the Annual Master Gardener's Seminar. I have his slide deck, and we asked him this very question at our CRFG meeting. He said the identical same thing - flood the pot.

Patty S.

Glad I read this, good to know.

Regarding lowering ph, a farmer told me that alfalfa meal is slow-release, dirt-cheap, and nearly impossible to burn plants with. I'm just wondering if any of you use it?

Some of my 20+ blueberry plants that need ph-lowering:
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Dax

Fruitnut,

You make it sounds like these are 100' maple trees. These are blueberries in pots, take them out of the pots, looosen the soil, thoroughly rinse the roots as best you can and put them into good soil......no big deal.

Several years ago I obtained some three year old plants from a friend that had been over-fertilized and had too much sulfur added to them. I took the plants out of the container, cut off the bottom half the rootballs which was mostly dead, trimmed off the dead branches above, and put them in new containers with pure peat. A year later the plants were thriving.

Yes you can flood the pot and keep tweaking the soil until you get it right and hope the plants don't die in the process or just give them a new home. To me, replacing the soil in a pot is by far the easiest and most certain way of gettting the correct soil environment.

RM

I grow blueberries in Wisconsin, & I suspect that we have similar soil to what is found in Illinois. Agricultural sulfur is used to lower pH successfully in our soil. Alfalfa meal would raise the level of nitrogen, and I'm sure it would have some effect on pH, but I doubt that it would lower pH down to the optimum level for blueberry shrubs, which is 4 to 5.

ericwi, thank you.

Dax

The procedure that riverman1 is talking about may need to be done if the plants are in the ground.