It wouldn't hurt, but may not be necessary. More important than the water's pH is it's alkalinity. Alkalinity is different than water with a high pH (alkaline:basic water). Alkalinity is a measurement of the water's ability to neutralize acids. The higher the alkalinity, the more acid it can neutralize.

If your pH is 8.2, but alkalinity is low it means that the pH of the water will rapidly change once it encounters an acid such as is released from peat moss or pine bark in the mix. The pH of the water in this case would have little meaningful affect on the plant's ability to assimilate nutrients properly.

On the other hand if the alkalinity is high then the acids from the peat/bark will be neutralized and the overall pH in the container will rise and continue rising over time until it is 8.2, the pH of your water.

For those with water supplied by a municipality, finding out if the water is high in alkalinity is as simple as an email or phone call to the water dept. In the case of your well I assume that at some point an overall quality test has been done? That test will likely indicate the alkalinity as well.

BTW, this doesn't just relate to container growing. If you have high alkalinity water, but your soil pH is, let's just say 7.0, areas receiving frequent irrigation will also see their pH rise over time. It generally takes longer in the soil than in a container as most soils have their pH fairly well buffered (sand would be an exception), but it occurs nontheless.

Thanks for the reply JaG. Much appreciated.

Here are the numbers from the test strip, visually compared to values in the test kit:

pH: 8.2
Chlorine: 0
Alkalinity: 160ppm

My understanding is that I should probably keep the pH value for water and soil somewhere around 6 or so, especially for conifers which prefer neutral or slightly acidic soil conditions.

I believe Al mentioned the gritty mix, when amended with gypsum, is somewhere around 6 or 6.5 pH. Just don't want the well water to raise the pH too much, hence the idea about using vinegar when irrigating.

Thanks!

Dave

Well, you aren't going to harm anything by using the vinegar. Since you have a means of testing pH, just add a TBS to a gallon and test it. It won't take very much vinegar to get the pH where you want it.

Good suggestion JaG.

Should I target a pH of 6 to 6.5 for the irrigation water to match the container pH? If so, then I can add vinegar to a gallon of water and figure out how much vinegar it takes to get my water down to the 6/6.5 range.

BTW, is it safe for th plants to add vinegar to irrigation water that already contains fertilizer and epsom salt?

Thanks.

Yes, but I am not sure if any reactions are possible if the fertilizer/vinegar are mixed in concentrated form.

I fill 5 gallon buckets with fertilizer, then the water, then add vinegar to the solution. I thought I recalled reading somewhere that some nutrient sources may have chemical reactions with the undiluted vinegar, but don't quote me on that. I figure it's best to just avoid the possibility by adding the vinegar to a weak solution.

I did a GW search and found a note from Al in a different fourm. From what I read in his post the irrigation water for most plants should be a pH value of 7 or less with an alkalinity of 0 to 100. (Mine is 8.2 pH and 160 alkalinity). Water with a pH over 7 and alkilinity over 100 may need adjustment, depending on the plant and soil type.

I think I'll pick up some white vinegar on the way home today and do a bit of experimenting with the well water, just to see how much vinegar it takes to get that water pH down to about 6 or so. I'll also check on the alkalinity and see what it reads.

To avoid any possible issues with vineagar and the MG fertilizer/epsom salt solutions, maybe I'll use the vinegar only with the irrigation water and not use it when adding the weekly fertilizer solution.

Sound like a good plan?

Thanks!

Sounds like a plan, but I regularly mix the vinegar in with the water/fertilizer solution and do not observe any reactions. My ASSUMPTION is that any reactions would be visible. Plus I usually fertilize every time I water so I don't have much choice ;)

Well I added 2 tbsp of white vinegar to a gallon of the well water. The pH dropped from 8.2+ to about 6. The alkalinity dropped from 160 to about 110.

Those are better numbers I think, so maybe I should do that each time I water and fertilize.

Thanks for the info and suggestions JaG. Much appreciated.

So by using the 2 tbsp of vinegar I was able to reduce the pH (8.2+ down to about 6) and the alkalinity of the well water. Since I'm growing plants (woody conifers) in containers that prefer pH in the 5 to 7 range,I think this might be a good way to adjust the irrigation water.

JaG, since you add vinegar into your fertilizer water then maybe I'll try to do the same. I mix about 1/2 tablespoon of MG 24-8-16 and 1/4 tsp of epsom salt in my fertilizer water and fertilize once a week. Once the MG and epsom salt are mixed I'll add the vinegar into that solution and see what happens. I just wasn't sure if using vinegar, MG and epsom salt together all at the same time would harm the plants in any way. If JaG and others on this list do it then must be the plants don't mind it either.

I'll keep you all posted.

Thanks.

Well yesterday I mixed up a couple of gallons of my regular fertilizer solution (MG 24-8-16 soluble plus epsom salt) and added 2 tbsp of vinegar. Tested the solution twice and the pH and alkalinity were approximately 6 and 110ppm respectively.

I then watered all the trees with the solution. We'll see how they like it. My guess is that they should be fine. JaG uses vinegar in his fertilizing solution each time he waters and he has great results.

Thanks.

Hi katsken41. I'm wondering if using a different fert might help this instead of using vinegar? You said you use "MG 24 8 16" which i think is a good overall fert. But what if you used something like a 30 10 10? I think that is made for plants that like more acid, like your trees.

Never used a 30 10 10 for my flowers and veggies but that might be worth looking in to and might keep the ph down a bit?

The fertilizers labeled as being for acid loving plants are a little bit of a scam.

Typically they derive most or all of their nitrogen from urea or ammonium sulfate, but then again most Miracle Grow type products do this regardless of whether they are labeled as being for acid loving plants or not. That's where the 'little bit of a scam' comes in. The N sources Miracle Grow type ferts use are the least expensive ones and they tend to produce acids so the label indicating it's for acid loving plants is really just to get the grower to buy yet another box.

It's true that these sources of N tend to produce acids over time, but they will do nothing to change the pH or alkalinity of the irrigation water itself.

Thanks JaG and pardak for your replies. When I first started container growing I used Miracid 30-10-10 for my conifer seedlings, thinking it was the best fertilizer for them since most conifers enjoy acidic soil. Once I started reading Al's posts about fertilizers I switched over to a more general 3-1-2 ratio fertilizer (the MG 24-8-16). This seems to work fine for my needs and the plants are doing very well.

Before I discovered that our well water was high in pH and alkalinity I never really thought about using a fertilizer that might reduce pH and alkalinity in water and soil, but from what JaG posted looks like Miracid wouldn't help anyway.

Adding the 2 tbsp of vinegar per gallon of fertilizing solution (including the MG and epsom salt) reduces the solution alkalinity and pH considerably. Judging from JaG and others it appears that adding small amounts of vinegar when watering does not harm plants so that is probably the best solution in this case.

I was a bit hesitant to try vinegar in my fertilizing water since I have used straight vinegar as a weed killer in the past.

Thanks again for the replies.

Dave

Before I discovered that our well water was high in pH and alkalinity I never really thought about using a fertilizer that might reduce pH and alkalinity in water and soil, but from what JaG posted looks like Miracid wouldn't help anyway.

I am bumping this post off page 2 because I just saw this reply and wanted to comment.

The MG type ferts typically deriving most of their nitrogen from urea *will* result in acids being formed in the mix itself. The formation of these acids can be very helpful in offsetting the pH raising effect of irrigation water with high alkalinity.

The distinction I want to make is that if one wishes to exercise greater control over the irrigation water itself, these ferts won't do that. The acids are the result of bacterial conversion from one N form to another. The actual fertilizer powder doesn't have the acids required to lower pH or alkalinity all by itself.

In other words, if you want to reduce pH/alkalinity of the water itself, add an acid to it. Vinegar is a safe, inexpensive, esy to find source of an acid (lemon juice would be fine too).

Using a fertilizer that forms acids goes the extra mile in that it will form acids inside the container that can then 'go to war' with with the various carbonates and bicarbonates that would otherwise raise pH introduced by the irrigation water.

As a side point, it's not necessary to accept a 30-10-10 formula (or whatever formula is currently being labeled as 'for acid loving plants'). Any of the water solubles that get most of their N from urea or ammonium sulfate will result in the acid formation occurring.