Soil ph and how water affects it.

2broke2smoke

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As I have recently begun a small outdoor grow I have been posting on other peeps soil grows. Recently I said that with dolimite lime in your soil there is no need to have a digital ph meter. As I expected I received feedback stating otherwise. Since it was not my thread I did not elaborate on my position. I will do that in this thread.
I am horrible typist so much of the information will be copy/paste with references.

We will start with the question will the ph of water affect the ph of soil?

Here comes the copy/paste:

"In some cases, your water source can have a significant influence on soil pH.
Soils have the capacity to resist changes in pH, but there are instances where the water pH can cause changes. Both the soil and the water contain negatively and positively charged ions that influence the chemical composition and thus the pH of soil. Some soils are more resistant to change, while other types can change rapidly if the water pH is significantly different from the soil matrix.

What Are The Characterisitics of Water pH?

The pH of pure water is related to the relative number of hydrogen and hydroxyl ions. If water has a higher proportion of hydrogen ions, it is acidic and has a pH less than 7. If it has a higher number of hydroxyl ions, then it is alkaline and has a pH of greater than 7. But water doesn't naturally exist without other mineral ions being present. This is especially true with groundwater and surface water sources. Carbonates and the calcium ion are common in groundwater sources, making for alkaline water sources. Rainwater is normally slightly acidic. And there is also acid rain to consider, which has both sulfates and a large surplus of hydrogen ions.

Why Soil pH Can Be Affected by Water pH

A soil's ability to be influenced by the pH of the water is related to its texture. Soil particles which are smaller, like clays and clay loams, are more influenced than coarse, sandy soils. Fine-textured soils have a higher number of very small particles called colloids. These colloids are sites where positively charged ions are retained. The ability of a soil to retain these ions is called its cation exchange capacity. Ions in the soil solution are exchanged with ions on the colloidal particles. Negative ions in the soil solution have less influence on soil pH.

Fine-Textured Soils Resist pH Changes

Soils with a high cation exchange capacity can resist pH changes due to the water source. This resistance to change is called the soil's buffering capacity. As pointed out before, finer textured soils are less affected than coarse sandy soils. A larger percentage of soil colloids results in stronger retention of positive ions like magnesium, aluminum and calcium and thus higher buffering capacity.

How Water pH Can Overwhelm the Buffering Capacity of a Soil

In normal rainwater and acid rain, there are excess hydrogen ions that can change soil pH by displacing calcium, aluminum and magnesium ions from the soil colloids. The buffering capacity becomes overwhelmed when the positive ions attached to the colloids are exchanged for the hydrogen ion from the water source. The calcium, aluminum and magnesium ions migrate downward in the soil profile and the soil becomes acidic. High rainfall areas are more prone to this problem, and acid rain can speed up the process.

In arid environments, soils are generally alkaline. This happens because of the alkaline minerals are in the upper soil horizons. Overcoming the high pH is necessary in many situations if one wants to grow plants that require a neutral or acidic soil, such as beans, melons and potatoes. Gardeners don't usually change the soil pH by lowering the water pH. Rather, they usually incorporate organic matter, an acidic fertilizer like ammonium sulfate or sulfur. These soil amendments leach out the excessive positively-charged ions on the soil particles and thus change the soil pH."

References:
About the Author
As a scientist, Randy McLaughlin has been a professional technical writer since 1980. He has a Master of Science from Texas A&M University and a Ph.D. in plant pathology from the University of Wisconsin. McLaughlin covers diverse topics, including Costa Rica, technical guides, alternative healing and spiritual development.

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2broke2smoke

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I add dolomite lime to my garden. Dolomite lime has a netural ph or ph 7.

Dolomite lime is a mineral from the earth which contains a natural form of calcium easily available to plants. The limestone it comes from occurs due to the accumulation of water borne minerals over eons of time.
As a very safe form of lime for gardens, there is almost no limit to its use as a conditioner in soils, especially those sandy and acid soils so common in the southern interior of British Columbia.

Wherever you see pine trees growing, that’s an indication that the soil will benefit from dolomite lime. Old time gardeners used it to ‘sweeten’ the soil and combat excessively acidic conditions.

In clay soils, dolomite lime will enable the clay particles to break up and become more friable, allowing better water drainage. It also enables the nutrients tied up by the pH to be released for use by the plants.

Find dolomite lime in garden shops and hardware stores
Gritty and heavy, dolomite lime is one of the most useful materials
Added in combination with organic matter it will improve most soils immensely in only a few years.

Used in specific garden beds to locally improve soil for growing Brassicas, peas and tomatoes it’s invaluable.

To prevent blossom end rot in tomatoes which is caused by a lack of calcium simply broadcast the dolomite lime along with ample compost over the soil.

If blossom end rot shows up later in the season, add more with a liberal application of compost tea to wash it into the soil.

Sprinkle it in trenches for direct seeding or for planting out young seedlings as it has virtually no risk of burning like hydrated lime which should never be used in a garden.

Sprinkled over lawns or gardens under coniferous trees it combats the acidity produced by many years of needle drop, and raises the pH of the soil enough to enable the release and use of nutrients. In cases like these, it's safe to use a large amount without bothering about pH testing.

Wood ashes are another pH adjuster that you can add to your garden.

The best way to use it seems to be to sprinkle it (dry) onto the surface of the soil and water it in

Think of dolomite lime as ph perfect for soil:D

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WeedHopper

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If your growing Organic thats a great additive. Never really had to worry with PH of my soil when i grew organically. Good stuff bro.
 
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