Question
QUESTION: Can I use dusting wettable sulphur to lower the PH of my soil for blueberries? Has it got chemicals added to the sulphur to make it wettable? The bag only says it's for diseases and insects.







ANSWER: Dusting "wettable" garden Sulfur is 90 percent Sulfur mixed with 10 percent Bentonite -- a type of clay from Wyoming that grips onto the water molecules and makes that mixture "wettable".

The same material is said to be added to some pesticides and fertilizers for the same reason, but we won't go into that in this forum.

Lowering Soil pH is a tricky undertaking.  The common (and in my opinion easiest and most successful) technique is to amend the soil with Elemental Sulfur (sold as "Flowers of Sulfur") or, sometimes, Iron Sulfate, or (when desperate) Aluminum Sulfate.  But I see no reason you can't use the "wettable" kind for this if you have no choice.  The Clay is natural.

Regardless, Sulfur additives won't work on all Soil -- if it has been limed, for instance.  But the reason Elemental Sulfur works is that the Soil bacteria use oxidizing Sulfides for energy.  That means it also won't work if conditions are not optimal for the bacterial doing all the work.  You need the right weather. You need patience (ideally, a year). You need air and moisture -- not for the Sulfur, but for the bacteria.

In addition, not all Sulfur is, well, Sulfur.  The Sulfur in fertilizer is Sulfate form, SO4 -2, and it won't lower pH in Soil. This is a complicated molecule with 11 known isotopes, highly flammable (gunpowder is made from it), lethal to Fungi but not to fish, soluble in Carbon Disulfide but not in Water, probably the most complex element in the Periodic Table.  Acidifying Bacteria (mainly Thiobacillus) obtain energy through oxidation of Sulfur compounds.

Note that Peat Moss, too, causes pH to plunge over time.  Have you got any?

A Soil test is crucial to getting just the right pH for your acid-loving plants.  And you don't have to go to a lab for this.  Once your treatments are underway, you can step in and sample the Soil to see how things are going:

1. Put a few drops of kitchen Vinegar in a small handful of dry Soil.  If you hear or see it fizz, you'll know that the pH is higher than 7.5.

2. Take a handful of moist Soil and Add sprinkle Baking Soda over it. If you hear fizzing, you can be sure the pH of your Soil sample is lower than 5.0.

Even your Blueberries will start to suffer if they have to endure that state too long.

I hope this was clear.  I've tried to distill as much as possible without leaving anything out in the translation. Any questions?


THE LONG ISLAND GARDENER


---------- FOLLOW-UP ----------

QUESTION: Thank you for such a detailed answer. I had my sandy soil tested and the PH was 7.5. I already added some sulfur but it didn't lower it much. Your test with vinegar or baking soda was interesting. What do you do if it's between 5.0 and 7.5? Mary Jo

Answer
Very sorry, Mary Jo, for making you wait all this time.  I though this question was taken care of.  Instead, it's been pending.  Here goes.

You say you've had your Soil tested, but it appears it was only tested for pH. If you know what your Soil is actually made of, you can make sounder decisions about questions like how to adjust the pH, or what fertilizer to use -- and even better, what fertilizers to avoid.

Why does pH matter? Important plant vitamins and minerals can't be absorbed when pH goes wrong.  Why should I care WHERE you are trying to do this?  It would provide a clue about the cause of the extreme pH.  If you were in Iowa, for instance, where pH can be off the charts (Iowa State experts place it in the range of 7.2 to a scalding 9.5), we'd know that the Soil is made of near pure Limestone.  Your 7.5 Soil pH suggests it's loaded with Calcium Carbonate.  Good luck altering that.  You've got to replace the Soil.

Sandy Soil that you describe has a low Cation Exchange Rate, meaning it won't hold a lot of those vitamins mentioned earlier.  Canadian Sphagnum Peatmoss pH is strongly acidic, between 3.0 and 4.5.  Get your hands on some, and blend it in.  Then add a healthy serving of Humus and/or Manure to give you something to work with and improve the Cation Exchange Rate.  But instead of dosing up your plants with old fashioned, 20th century fertilizer, consider taking advantage of some of the science-based products that are gradually coming to market.

My current favorite: The line put out by bioscientists at Plant Health Care, plc, and its U.S. branch Plant Health Care, Inc., in Pennsylvania. PHC bought the rights to sell Cornell-patented Harpin Protein after the previous company bungled the marketing.  PHC also sells Soil MICROBES, tiny, microscopic nutrition powerhouses that work hundreds of times more effectively at pumping nutrients into plants.  In your case, your sandy Soil DESPERATELY needs Microbes.  And get this:  Microbial action lowers Soil pH.  Here's their U.S. website:

www.planthealthcare.com/HT/Home

PHC's 'Myconite' contains spores of Friendly Fungi. Once activated, they burst into action, colonizing root hairs on local plants and shooting nutrients right into the bloodstream.  The lucky plant thanks them by sending back Carbon that it doesn't need.  The Fungi use it for energy.  Everyone's happy.

There are other lines, too. But PHC has the market cornered on Harpin Protein, an Earth-friendly chemical cure for sick or damaged plant tissue.  That's the stuff they used to call 'Messenger' that was discovered by Cornell University scientists.

If you're not sold on the idea of using, say, Fungus Spores to help build up your Soil, consider this:  Penicillin, Ampicillin, Streptomycin and sundry other miracle antibiotics are all Fungi.  They save human lives.  Think what they could do for your plants.

To summarize: Amend your Soil with hefty quantities of Humus and Manure to boost organic matter and put some meat and potatoes on the table.  Get your hands on some Flowers of Sulfate and use according to directions on the package.  Re-treat as necessary.  If you can, instead of letting the Soil sit around, plant Alfalfa or Wheatgrass.  Test your Soil.  Churn in the Alfalfa when you are ready to use the Soil.  Sprinkle on a Microbes product according to manufacturer directions, then plant.  Keep me posted.

THE LONG ISLAND GARDENER