Water pH & it's effect on gardens & plants

[Wilson]

I have a drilled well that goes down 220'. When it was drilled in 1995, the pH that came back with the first water test was 7.0, perfectly neutral.

Over the years, I've had some plants begin to give me problems that took a while for me to notice developing as I thought it was just a year to year change in local conditions.

This year, in the spring while natural rain was sufficient, I remember remarking to my wife, 'Go look at the cucumbers if you want to see some nice dark green foliage.' During the past few years, my cukes have dropped off in production and the leaves are more yellow than dark green. This year we made no cucumber pickles and barely had enough for sandwiches.

I maintain a totally organic garden making compost & using some aged hen manure that is mixed with softwood chips in their bedding, so I doubted that the yellow leaves came from a lack of nitrogen. Also, these are raised beds (3' x 10' x 10") and have good drainage.

This year, after testing the mother-in-laws water and finding a level of coliforms higher than zero, I retested my own. I found that my pH had risen to 8.7.

But before testing, as the springs rain slowed, I began using a 'wand' waterer on my hose which puts down a lot of water fast. Within a couple of weeks, I noticed that the cukes were yellowing, my zukes wouldn't set fruit, indeterminate tomatoes failed to achieve their usual height and her garlic shriveled up and disappeared.

I sifted the garlic bed and saved all the bulbs I could find. In August, we got 18" of rain & I stopped watering with the well water. New garlic sprouted from the tiny bulbs I missed and are still growing lushly.

I'm going to switch to rain water next year. However, I can't find anything when I search on the effects of high pH water on plants. Nor have I any idea why my pH would change. Anyone else seen this happen?

[Billy]

No.

Who are your neighbors (residential, commercial, bucolic), and could they be affecting your well?

Lots of alkalin water on well drained soil, will affect its pH. Sulfur is your friend.

Otherwise it is the usual litany: where are you, what agricultural zone, what kind of soil, what is the soil pH, and how much sun do you get?

[David Hare-Scott]

I have no idea why the pH of your well water changed but I doubt you can alter it. I also doubt that the water is doing much directly to your plants but it may be altering the pH of your soil which will make a difference. The effect of high pH in the soil is to lock up some minerals by making them less soluble, this produces deficiencies in plants. A pH of 8.7 is quite high for a garden soil, not that it is certain your soil will necessarily be that high just because you are using water of that pH.

You should test the pH of your soil before going any further. I find the best kind of test is using dye indicators, a kit will cost maybe $20 and will do many tests. These kits are sufficiently accurate and reliable for the purpose, cheap electrical probe systems are not. I would stop using that water except in emergencies as it will slowly deposit minerals in your soil that will eventually raise the pH of the soil. For most plants (there are exceptions) a pH of about 6-7 is desired. If your soil's pH has in fact risen much above 7 you may have to amend it to lower it again or stick to alkali tolerant plants.

David

[Gunner]

44.69, -67.3 : Long/Lat? Acadia region of Maine? If so, have you considered seawater infiltration? This link is bit wordy but it may give some hydrology insight: well as:

From a hydrological or geological aspect, its highly unlikely any watering in your life time is going to reach 200+ ft depth. So it is also highly unlikely that surface contaminants are involved in your water from either you or your neighbors If you ARE in Maine, pretty much granite thus iron, isn't it? Don't see much limestone sources in your region as a possible. Regardless, it would take a huge amount of minerals (organic or inorganic) to change a pH factor by 1.7.

So with your stated practices and my region guess, it doesn't sound like your soil is the causative here and 8.7 is in pH range of seawater. So you may have or had zones of seawater infiltration in your aquifer, ergo, a myriad of elements would be present that would cause your plant's chlorosis. Consider an analysis beyond pH testing as proper protocol to specifically identify what is going on and take immediate corrective action. Otherwise, you risk test trials of every Garden Guru's " have ya tried..." theory. Those are usually based on highly biased folk lore and/or personal bent which usually just eat up time and money.

Recommend as a start you give your County AG Extension office a call as well as have your water analyzed for more than just pH and test your present soil conditions to see where they stand. Think about it a minute... with today's testing procedures, you would mostly likely have already had a scientific starting point and a course of action plan to test off of.

Good luck Wilson and please update what and how you do.

[Wilson]

I have both the probe type pH tester & the liquid ones. Never put much stock in the liquid type as it seems rather subjective to try to determine the proper color of now muddied water. Also, if I use my well water (pH 8.7) to perform the test, won't my reading be higher than if I used distilled water with a pH of 7.0? Going one further, if my soil is higher or lower than 7.0, won't distilled water move the results toward the neutral 7.0?

But my real question is about the effect of continued high pH or alkaline water on my plants. I can tell you it's not neutral from my experience, but am at a loss as to why I can't find info on when I search.

Like I said, it will be rain water for me next year or I might try to adjust a 50 gal. barrel of well water with some 5% acid vinegar. Now, if I could just find a good formula or equation for calculating the amount of vinegar to adjust 50 gals. of pH 8.7 water down to say 6.5, I might be in good shape.

Thanks to you & Billy for your replies.

[Wilson]

as well as: .

You have my area correct and we do hear from time to time that drilled wells are high in salt & need to be re-drilled. As you said, ground level activity isn't likely to affect the aquifer 200+ feet down unless some sort of crack in the ledge runs vertical.

The one thing that concerns me is that, while I'm in an area with low population density and am, in fact, living in the woods, I live near a Navy base which has been 'abandoned' and rezoned for housing. This base had it's own reservoir & water treatment plant, but since giving it away to the town, almost everyone of the houses on the base has had a drilled well put in and all are within a half mile of my well. I suspect that these new wells have put such a demand on the aquifer that the flow pattern of the aquifer might have been changed. And yes, I'm within a half mile from the ocean, so sea water sounds more plausible if the base wells have lowered the 'pressure' of aquifer resulting in new sources feeding it. God, I hope that isn't the case.

As for my failed garlic crop, I had that raised bed tested this past summer and the soil tested with a pH of 7.2.

[David Hare-Scott]

I have not had that problem as the one that I have comes with an insoluble white powder that is use to give a constant colour to read the dye against. Also I don't know why you have muddy water the dye indicator I use works on a solid sample. The _cheap_ probe sort are not reliable in my experience as they depend on water content of the soil to get a reading, the expensive ones (ie glass electrode) can be up to laboratory standard.

So what is the pH of your soil by each method?

Also, if I use my

Why do you need any water to perform the test? Both systems ought to work without it. What brand of dye indicator do you have, does the manufacturer have a web site?

Going one further,

Not appreciably but it's a non issue - see above.

I explained this before, pH determines the solubility of minerals which determines their availability to the plants. There are many thousands of references to this on the web I cannot understand how you can't find one.

Start here:

You will not find 'a good formula' to adjust the pH of your water, it isn't that simple. Also if you can water your garden satisfactorily with a 50 gal barrel you could use rain or tap water and forget all about the well, assuming that the well water is in fact the cause of your problems.

There is no certainty the soil is as alkaline as the water you put on it. Until you tell us the pH of your soil there isn't much more to say.

David