WeedzEatR

Ok, lets say that the PH of my soil is 5.5..
To bring it up (around 6.5), do I need just to add some tap water with a PH of 6.5? or it need a water with an higher PH (like 7.5) to bring it at a middle? or does it need more than just water!?

I don't know if my question make sense, but I try to up my PH, and it seems to stay low..

If someone can help me...

Thanks!

ciratac

pH is a measure of how acidic or alkaline a solution is. It ranges up to 14, with 7.0
being exactly in the middle, neither acidic nor alkaline. Pure water with nothing dissolved
in it is 7.0. A lower number means more acidic, and a higher number means more alkaline
(or "basic": a base is the opposite of an acid).

Anyway, to lower pH, you add something acidic, like vinegar (acetic acid). To raise it, add
something basic, like baking soda dissolved in water.

You probably don't want to use these household things in plants though, as they
may leave unwanted stuff in the soil.

Any garden center should have some sort of pH-up or pH-down product.

Typically with gardens, if the soil is too acidic, gardeners mix in lime (crushed limestone,
not the fruit). I believe you could dissolve some lime in water and use that to raise
the pH of your soil.

I'm no expert on this. Anyone else care to weigh in?


-ciratac-

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Lizzie Borden

Good info, ciratac.

If your soil pH is 5.5 and you want to raise it to 6.5, you should add water higher than 6.5. It won't necessarily meet exactly in the middle though.

But changing the pH by adding pH up and down type products to water is temporary. This is because of buffers in the soil which tend to swing the pH back to what it's "buffered" at. You can add enough acid or base to overcome the buffers, but then the pH becomes unstable. I have had better luck maintaining a correct pH by adjusting the amounts of peat moss and lime in the soil mix. This takes some experimentation to find out what works with your tap water and ferts.

If lime is soluble, I don't see why you couldn't dissolve some in water and use that to buffer the soil to a higher pH.

3hounds

Does is say "dolomitic" or "agricultural" or "hydrated" lime on the label?

A 10 X 10 area (100 sq.ft.) requires about 3 lb. of dolimitic lime to raise the pH one unit in good, freely draining soil. Heavier soils can need up to nearly 10 lbs. for the same effect. You can either mix it with water and apply, or broadcast it and water it in.
The result is not immediate, though... depending on rainfall, temperature, and a host of other factors it can take as long as 6 months for the pH to change.

Hydrated lime (the stuff they make concrete with) is faster acting (immediate!), but does not last well in free draining soils- more suitable for heavier clay soil. It is also the “strongest” form of lime, and will burn both skin and eyes... hurts like a mother if you accidentally inhale it. It is a very fine powder and with the least breeze you lose half of it before it hits the ground.
I use the agricultural stuff as I have a very sandy soil, and am ammending for the long term, not just one crop. I have used hydrated when it was all I could find.. I just find it more difficult to work with.

In altering pH for a quick crop like "ours" hydrated lime might better suit your needs.

I would suggest adding it maybe a tablespoon at a time to a gallon of water and testing the pH of that water. When it gets to roughly 7.5-7.8 I would water with it, then check the soil pH the next day, and periodically thereafter.

I do agree that ammending the soil at the beginning is much easier, if you use the same ammendments each time and know your soil mix well.

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ciratac

While we're on the topic, does soil pH typically change during a growing season? It doesn't
seem unreasonable to expect that as stuff breaks down, and plants take some of it
up from the soil, that the composition might change in a way to alter the pH.

Or, put another way, does soil pH need to be corrected at the beginning of each growing
season, or is once typically enough?

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WeedzEatR

Thanks for all the replies!
If my tap water has a PH around 8-8.5 (the PH is high here!), can i just use it to raise the PH? or should i try to lower a bit before?

btw, I have just a little garden, 3 little plants in pots..

ciratac

Wow, 8 to 8.5? That's really high. Does it foam when you mix it with vinegar?

You could just use some of that and see what happens. If you're worried that it's too
high, you could mix it with distilled water to lower it.

Even if this changes the pH, it might not stay that way, for the reason that Brindie
mentioned. Whatever is in the water that makes its pH high might not stay in the soil.

But it's worth a try, IMO, since you have it right there coming out of the tap.

By the way, how are you measuring the pH? Are you sure your measurements are
accurate? It might be worth doing a measurement on distilled water to make
sure you get 7.0.

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3hounds

In my own experience (and I have very poor 'soil') is that it is a long term, ongoing project. You strive towards an ideal, knowing you'll never get there.

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Lizzie Borden

One of the benefits of compost is it tends to pull the pH towards 6.5. I can't remember if I read that about compost in general or horse manure compost, which is what I use.

WeedzEatR

I begin to believe that my water test is not ok.. I have 2 aquarium test from Hagen, 1 with a PH between 4.5 and 9, and the other from 6 to 7.5... I've tested my tap water yesterday, and the 2 tests was over the max... a PH over 9?!? is it possible?
I was using some pure apple vinegar to bring it down, but I guess, like Ciratac said, it may leave unwanted stuff in the soil.. and maybe too much vinegar..
hmm.. what to do...