Soil Composition

[arcanedeity]

Hello all. I have recently received my soil test results. Most of it seems to be fine for gardening. My ph, however, is 7.4. Now I know that tomatoes like slightly acidic soil. But this got me wondering. What is the highest ph you guys have grown tomatoes in? Also any advice on how to lower the ph would be just dandy, if I need to.

[Gardeneer]

Yes, you are right. Tomatoes and most garden veggies like slightly acid soil. But they can thrive
in pH range of 5.6 to 6.8. That is according my soil test results. Mine is 6.2 to 6.5 (different beds).
To reduce pH need to add things like "Iron Sulfate". They recommend 3 lbs per cubic yard to reduce pH by 1 unit (e.g from 7.5 to 6.5 ).

But to directly answer your question : I have never had high pH issue, but the opposite.

Gardeneer

[ilex]

I have 8.5, water is higher. Only some in the boar series complain. I grow about 100 varieties a year.

I think tomatoes don't care about ph. They don't like reading books so don't know what they can or can't do.

7.4 is almost neutral, you shouldn't have problems with most plants.

[Andrey_BY]

Tomatoes may not like reading books and newspapers, but if your soil pH is 6-6.8 they will certainly say "thank you" with better desease tolerance and the best productivity.

The pH affects whether fertilizer and other nutrients in the soil are actually available to your plants. If they are hardly available to your plants in the case of tomatoes, peppers, and a few other vegetables, it contributes to a problem called blossom end rot.

You should check the pH level in your garden every 2-3 years.

If your soil pH is too low (too acid), you'll need to add lime to the soil to bring the pH back into the proper range.

When your pH is >7 tomato foliage is getting yellow due to iron blocking.
Rarely is an iron deficiency in plants caused by a lack of iron in the soil. Iron is typically abundant in the soil, but a variety of soil conditions can limit how well a plant can get to the iron in the soil. Iron chlorosis in plants is normally cause by high pH.

If you have high pH or alkaline soils you need to add iron sulfate, aluminum sulfate, and powdered sulfur. Compare products and follow label directions.

Although lime and sulfur can be added to the soil any time the ground isn't frozen, fall is a convenient time for many gardeners and gives slow-acting lime a chance to take effect.

[PureHarvest]

Originally Posted by arcanedeity

Hello all. I have recently received my soil test results. Most of it seems to be fine for gardening. My ph, however, is 7.4. Now I know that tomatoes like slightly acidic soil. But this got me wondering. What is the highest ph you guys have grown tomatoes in? Also any advice on how to lower the ph would be just dandy, if I need to.

You need to look at WHY your pH is 7.4
This will give you a much more accurate idea of what to add.

I like the analogy of taking your temperature. You might know something is off with a high temperature, but you might not know exactly why it is off. Taking an aspirin may temporarily lower your temp, but if you don't change the underlying cause, you will still have issues eventually or cause other imbalances.

And remember that pH from one point to the next is a huge jump.
6 is TEN times more acid than 7.
5 is ONE HUNDRED times more acid than 7.
So your 7.4 is 10 times more alkaline than 6.4

[bower]

Originally Posted by PureHarvest

And remember that pH from one point to the next is a huge jump.
6 is TEN times more acid than 7.
5 is ONE HUNDRED times more acid than 7.
So your 7.4 is 10 times more alkaline than 6.4

So... is pH 4 a thousand times more acid than 7?
If my container soils ever get too alkaline, I guess I could fix it with a pinch of the native clay outside.

[Gardeneer]

Originally Posted by bower

So... is pH 4 a thousand times more acid than 7?
If my container soils ever get too alkaline, I guess I could fix it with a pinch of the native clay outside.

It is a logarithmic/ exponential function. Let me give you an example

Household vinegar (5% acidity) has a pH of 2.40.
-- mix 50/50 ( v/w) : the pH will be 2.56
-- mix 12.5/ 87.5 (v/w) the pH will be 2.86
.....
That is why changing pH (in either direction) needs a lot of acid or alkaline.
Gardeneer

[arcanedeity]

Thanks. I knew about the logarithmic nature of pH, but was curious as to what that translates to in the practical world of amending soil. I know that changing pH takes time, especially if I am addressing the root of the problem. I live in what used to be a river bed some 100 years ago. I plan on adding organic material and the like, but that takes time. Just dont want my efforts to be in vain.

[ilex]

We don't get yellow plants around here.

I've seen books saying it is impossible to grow orange trees here due to alkaline soil. Well, that's what everybody grows.

[Andrey_BY]

Ilex,
it is not only about Iron chlorosis or any other decease like BER. It is mostly about how your tomato plants get feeding... But I don't think there are any problems if you don't see them at your growing conditions

And about citrus growing outside - that's what I've been always dreaming about, but frost is here...
Growing them indoors is quite complicated as well when you are not a private house owner and you've got windows to the Noth and East at your flat...

Originally Posted by ilex

We don't get yellow plants around here.

I've seen books saying it is impossible to grow orange trees here due to alkaline soil. Well, that's what everybody grows.

[PaulF]

My soil, and most soil in my area, has a natural pH of 8.0 to 8.6. By adding elemental sulphur, occasionally Ammonium Sulphate, lots of compost and other nutrients the soil test calls for, over the past dozen years the tomatoes still grow despite pH being much higher than optimum. No matter what steps are taken to lower pH, after a while (a couple of years) the soil tends to return to its natural state. It is a constant battle but that is all part of the fun of seeing what we can get out of what we have.

The soil in my garden is loess (pronounced 'luss') which is wind blown volcanic dust from the Rockies a few million years ago. It grows great weeds and trees and other vegetation that has acclimated to the high pH soil. Non-naturals like tomatoes and peppers and lots of other plants need help.

[RayR]

Everybody has different native soils here, it's like comparing apples to oranges. My soil is slightly alkaline too, around 7.3. That is not a problem for growing most plants. Trying to change the PH chemically is a long term and many times a fruitless activity. Soils are buffered at a certain PH and will resist any permanent change. You may be able to lower or raise PH temporarily but soils can be very stubborn and will return back to their buffered PH.
It's a lot easier to control PH in a raised bed or container with a soil-less medium than it is in native soils.
The place where PH really counts is right around the plant rhizosphere. Root exudates will change the PH up or down depending on what nutrients the plant is trying to take up, so the plant has some control there. The bacterial and fungal partners of the plant will also modify PH around the roots and also naturally chelate many nutrients so their root uptake is not dependent on PH. If your plants are not performing because your PH is too low or too high, concentrate on improving the soil biology and let nature do its thing at controlling PH.

[arcanedeity]

Originally Posted by RayR

Everybody has different native soils here, it's like comparing apples to oranges. My soil is slightly alkaline too, around 7.3. That is not a problem for growing most plants. Trying to change the PH chemically is a long term and many times a fruitless activity. Soils are buffered at a certain PH and will resist any permanent change. You may be able to lower or raise PH temporarily but soils can be very stubborn and will return back to their buffered PH.
It's a lot easier to control PH in a raised bed or container with a soil-less medium than it is in native soils.
The place where PH really counts is right around the plant rhizosphere. Root exudates will change the PH up or down depending on what nutrients the plant is trying to take up, so the plant has some control there. The bacterial and fungal partners of the plant will also modify PH around the roots and also naturally chelate many nutrients so their root uptake is not dependent on PH. If your plants are not performing because your PH is too low or too high, concentrate on improving the soil biology and let nature do its thing at controlling PH.

Thanks Ray. I have been reading up on what affects pH and was leaning toward an answer such as this. Its amazing how everything is connected in soil biology.

[arcanedeity]

For those that were curious. Here are the results of my soil test: 2% organic matter, 91 ppm for phosphorus, 226 ppm for potassium, 284 ppm for magnesium, 12 ppm for nitrogen, calcium is at a whopping 1938 ppm (Im guessing this is related to the pH), sodium is at 15 ppm, soluble salts are at 0.2 mmhos/cm, pH is at 7.4, excess lime rate is low, and the C.E.C. is 12.7. Right now, I am researching ways to mobilize the calcium. Is the C.E.C. related?

[PureHarvest]

Originally Posted by arcanedeity

For those that were curious. Here are the results of my soil test: 2% organic matter, 91 ppm for phosphorus, 226 ppm for potassium, 284 ppm for magnesium, 12 ppm for nitrogen, calcium is at a whopping 1938 ppm (Im guessing this is related to the pH), sodium is at 15 ppm, soluble salts are at 0.2 mmhos/cm, pH is at 7.4, excess lime rate is low, and the C.E.C. is 12.7. Right now, I am researching ways to mobilize the calcium. Is the C.E.C. related?

If you can give the base saturation percentages, I can tell you what is going on with your cations. I can calculate them but you did not list Hydrogen.