My well water is pretty high pH, (alkaline) and a lot of my plants get very chlorotic in the spring and fall months when I irrigate a lot. They are all beautifully healthy and green now because we had such a rainy summer, but I am looking sadly forward to the dry weather that's coming.

Is there a good way for me to treat the well water to lower the pH? Preferably without breaking the bank . .. Surely farmers must address this problem in some places?

I think baking soda will lower the PH. That's what I use in the hot tub. Let's see if you get a better answer.

A lot of organic matter breaks down into acidic compounds. Around here, pine needles are abundant, and mulching with them will make for acidic soil over time. I'm not sure if you have a source of pine needles or similar organics, but no price beats free, and mulching has a lot of other benefits as well. I don't think regular leaves are quite as effective as pine, but given that you're in Florida, it makes me wonder if palm fronds would have a similar effect.

If you need a stronger, faster acidity boost, you can work a bit of aluminum sulfate into the soil surface. I find it pretty inexpensive at my local garden center, but I could see the cost adding up if you are farming large-scale. Since my soil is naturally acidic due to the decades (centuries?) of pine needles that have fed it, I only use it on acid-loving plants (blueberries), rather than the whole garden. Be careful with it - too much can easily burn plants, especially those that prefer a slightly alkaline soil, so I'd limit it to plants that you know suffer from the well water.

Julia, a baking soda solution (because something has to be in solution to have a pH) is actually somewhat alkaline (pH around 9), so it would probably not help Elaine.

(Sorry for the double post. You replied while I was typing, or I would have mentioned it above.)

I was thinking of treating the water but I was going the wronging way.

Yeah, it would be a good solution to raise pH

I'm not sure whether the aluminum sulfate I mentioned can be added to water or not. I irrigate with rain water, which is naturally acidic, so treating the water is something I haven't considered. That brings me to another thought - Elaine, would installing a rain barrel be an option for you? Atlantic-derived rainwater is around pH 5-6, and it can be much lower if your clouds form inland, but I couldn't find info on the Gulf.

Thanks, ladies. Good thoughts all. I do have rain barrels, and two 600gal. rainwater cisterns. That water is 'reserved' for the orchids, vegetables and fruit trees. Even with well over 1000 gallons in reserve I run out of rainwater on a regular basis in the hot, dry months in spring and fall. The fatal flaw of collecting rainwater, it doesn't replenish itself when you need it the most, right? Spring and fall are the main growing season for vegetables here, and also the driest times of the year.

But the rest of the landscape - about 1/4 acre - is watered during the dry months with the well water that comes from 150ft. underground, and runs through Florida's fabulous limestone aquifer. I was thinking of something as simple as a drip system into the pump, with vinegar or something else acidic. But it would probably use gallons and gallons of the acidifier and be high-maintenance and expensive. Maybe if I post my question in the Farming forum somebody will have an idea, do you think?

Treating the acid-lovers with some aluminum sulphate might be my solution if I can't find a way to balance the well water reasonably. Thanks!

Elaine, a recent article by LariAnn (Aroideana vol. 36) refers to a product called Take Down, 70% phosphoric Acid, to neutralize her water. Purchased at a local farm supply store. Pine Needles, once brown, they don't add significant acidity to soil, even over time.

Ah ha! Thanks Evan. Perhaps the 'Take Down' product is what I'm looking for. Will check farm supply for more info on how to introduce it into the system.

I don't have pines in any case, but there are 4 huge old oak trees around the house that have been dropping leaves for a century or more. Their leaves are acidic, too. But even in the shady border under these oaks, the Heliconias and some other more sensitive plants turn chlorotic after a couple of months of well water irrigation. I 'mulch' those beds with the oak leaves, too! (i.e blow all the leaves into the beds with the leaf blower . . ) Obviously the slow break-down of the acidic leaves isn't enough to buffer the fast introduction of alkaline well water once I start irrigating regularly.

I'll bet the Ears are pretty sensitive to pH level in their water too, but seems that mine are not in that active growth until the rain starts, so I haven't seen chlorosis on them particularly.

Our well water has high pH as well as a high "total alkalinity" number. The latter is the bigger problem because it has longer lasting effects. A high alkalinity number means that the water resists acidification. Essentially it is like watering with a mild liquid limestone. That's been okay for us in East Texas because our soil is extremely acidic, so watering with high alkalinity water is fairly preferable, as far as I've been able to see. I'm guessing it helps to counteract the acidity in the soil. But if our soil wasn't acidic to start with, I know we'd have a big problem on our hands. Our water has over 600 ppm total alkalinity.

Good luck and please keep us posted. I'd wager many FL gardeners have this problem. On the bright side there are some really cool Amorphophallus which grow naturally on limestone.

Ah, yes! Total alkalinity . . Just went and did a quick test with my swimming pool test kit, and it's not good, the test strip I used only went up to 720, and the reading was at least that high. <sigh> It might be cost-prohibitive to do what I'm wanting, considering the acidic additives seem to run around $26 per gallon. But I really only irrigate with the well water for about 4 months of the year, in the hot weather in spring and fall.

But I am sure that at least greenhouse growers (of which there are thousands in FL) must address this problem so there is a relatively simple solution. That's where I've directed my quest.

Our soil is basically sand, so slightly on the alkaline side to begin with. Miles from the beach, you dig up shells in your garden here.

Amorphophallus? Evan! You know what I think about stinky flowers. A flower's gotta smell nice or it has no place in my garden!

There are fertilizing programs that commercial growers use to address this issue. As for me, I just grin and bear it. As you said, one only irrigates for a few months out of the year.

Yeah, the option of just treating the sensitive plants in question with something like ammonium sulphate is looking more attractive.

I put my DH on the problem, and he (a mechanical engineer) is now all wrapped up in fancy complicated computerized dispensing systems and the projected cost is going into the stratosphere. I shoulda known better . ..

Pure elemental sulfur might be cheaper than aluminum sulfate. I see there are sulfer products that are OMRI listed (organic).

Straight sulfur Is probably not very fast acting. Microbes gradually oxidize it and combine it with water, which in effect produces sulfuric acid (H2SO4). That immediately counteracts some of your alkaline water (OH-).


The most finely powdered sulfur you can get is better - or rather, faster. Whatever is cheapest is probably best. I see "CSC Wettable Sulfur - EPA Approved for Feedstock" and a fancier products called "Disper-Sul® ". $2 to $4 per pound. 99.5%+ Ground Yellow Sulfur Powder

In the lab, it was called "flowers of sulfur" but that might be ancient terminology.

HERE we go! A 50 pound bag for $22.50. 45 cents per pound sounds better.
http://www.arbico-organics.com...

"TIGER 90 CR® Organic Sulphur 0-0-0-90 is ideal for soil amendment purposes when a soil test result shows a high pH (above 7.0 and especially above 8), as well as high sodium and high lime (above 1.0%). Soil with such a high pH value is considered alkaline, and its high pH value causes essential nutrients to be unavailable for crops. One of the most cost-effective ways to lower pH is to apply Tiger Organic 0-0-0-90, a granulated product made up of thousands of tiny particles of sulfur per granule. Tiger 90 CR is mixed with Bentonite clay in a special time-release formula. It is OMRI listed and WSDA registered for use in organic farming.

As TIGER 90 CR® Organic Sulphur decomposes and lowers your soil pH, it will react with the free lime in the soil, which will add gypsum (high in calcium) to the soil and free up the sodium to be leached out by watering.."

That sounds like some great stuff. Thanks Rick.

What about Epsom Salt's? doesn't that lower PH? Also works wonders as a foliage spray.


http://www.garden.org/articles...

You're very welcome! I used toi wonder how soemthing as boand as elemental sulfur could become an acid, until someone told me or I looked it up. then it seemed like magic.

In fact, one pound of pure sulfur (S) would become the equivalent of 3 pounds of 100% sulfuric acid, or 61 pounds of 5% sulfuric acid ... call it 6 gallons of dilute acid from one pound of sulfur powder.

Respect the sulfur- oxidizing bacteria! (e.g. Beggiatoa and Paracoccus).

Yes, Epsom salts is Magnesium sulphate, and it does have the potential to lower the pH, but I think you'd have to use way too much of it to neutralize my pH 8.5 well water, irrigating half my garden.

I have a half gallon of my well water sitting on the kitchen counter, so maybe I will experiment and see how much Epsom salts I have to add to it to get it down to a pH of 7.

Good thought! Thank Susan.

Well, what if you just spray it on the leaves.