pH and Your Rose Soil

Melody Perfumee

Melody Perfumee, Photo By: Irene Hannestad

A soil test is essential to planning for that new garden or changing one to accommodate new conditions. At the least, a test of the soil's pH is necessary to determine the health and vitality of the ground into which you plan to invest your landscape dollars.

Simply put, pH is a chemical term used to express hydrogen ionization in water. The term refers to potential hydrogen and indicates the breakdown of water (H2O), normally a stable molecule, into a positively-charged hydrogen ion and a negatively-charged hydrogen-oxygen molecule (HO).

The soil's acidity or alkalinity is determined by this ionization. It occurs when the various minerals and organic materials combine with water molecules forcing the soil to change its properties.

Luster Leaf 1817 Rapitest Mini Soil pH/Moisture Tester

We measure this ionization on a scale from 0 to 14. Neutral soils are said to have a pH of 7, or midway up the scale. Acid soils are those with a pH of less than 7, and alkaline soils are those with a pH above 7.

Soils with an extremely low pH – very acid soils – are said to be sour. Conversely, soils with a high pH are said to be sweet.

So much for the scientific jargon. What is important to you is the knowledge that pH directly affects your soils health. And your soils health, in turn, directly affects your plants health. And finally, your plants health directly affects its susceptibility to disease and insects, which may require you to apply pesticides which, in turn, may directly affect your health and the environment!

Most plants will not tolerate a soil with extremes in pH. The reason for this intolerance is because pH affects the release of essential elements necessary for the plant’s growth and vitality.

Nitrogen (chemical symbol N) the element we hear about most often. It is the primary element that affects productivity of plant life. That is, it is directly responsible for vegetative growth in plants. Without nitrogen, the plants leaves lack their lush green color and growth is stunted. In soils with very low or very high pH, nitrogen is trapped – a condition most plants cannot tolerate.

Phosphorous (P) is essential for strong roots, flower and fruit development, and resistance to disease. It too can be trapped in soils that are excessively out of neutral in pH. Recent tests have shown many soils have excessive amounts of phosphorous that has accumulated by excessive application of synthetic fertilizers onto tight clay soils. One of the reasons for this accumulation is that these normally high pH soils prevent the plant from using all the phosphorous that is available.

Potassium (K) is the third important element in soil health. Most often, plants us the form of potassium known as potash or potassium oxide (K2O). Potassium is essential to the plant's ability to create sugars. It is also essential to the plants capacity to resist disease, survive cold temperatures, and provide drought protection. It is less susceptible to variations in soil pH, but can be significantly trapped when soils are at their extremes in alkalinity or acidity.

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