I was asked to give a presentation to the August 11th lunch time crowd during the "South western Low Desert Landscaping and Gardening Conference" held at the Arizona Biltmore Hotel in Phoenix. The assigned topic was Wives Tales and Snake Oils. I added "Gardening Myths" to the title. Several of the conference participants were from Cochise County and they requested that I write my presentation for the Cochise County Master Gardener Newsletter.

Myth #1: Soil structure and chemistry can be changed with amendments. Soil is huge; it is under our feet everywhere. The weight of one cubic foot of soil is from 80 to 120 pounds depending on the soil type. Many western desert soils have from 1 to 10% free lime or calcium carbonate. In our desert soils we have alkaline soil pH's. This is because of the calcium carbonate content of the soil. It is not leached through the soil because of our limited rainfall. Back in the East and the Mid-west the high rainfall amounts removes the calcium by leaching and the result is acid soils. Assuming a cubic foot of soil weighs 100 pounds and has a 1% calcium carbonate content then there would be one pound of calcium carbonate present. It takes one pound of sulfuric add or its equivalent to neutralize one pound of calcium carbonate. Therefore, to decease soil pH from alkaline to neutral or add it would require equal mixing of one pound or equivalent of sulfuric acid throughout the cubic foot of soil. If the soil had 10% calcium carbonate then 10 pounds of sulfuric add or its equivalent would be needed to neutralize the soil. This is not cost effective to do and is not going to happen. We need to learn to work with the soil we have on our property.

Myth # 2: Chemical fertilizers harm the soil and the organisms in it. The soil is a dynamic, living world of microscopic bacteria, fungi, nematodes and other organisms which are not static but constantly changing. When anything is added to the soil there is a reaction in terms of soil chemistry and organism. "For every action there is an opposite and equal reaction" applies to the soil. As a fertilizer is added to the soil whether, from a "chemical" or "organic" source, the population and ratio of organisms changes. If the fertilizer is high in nitrate-nitrogen the bacteria and fungi that consume it will increase in population, perhaps "pushing out" of balance other organisms for a while. What the nitrate-nitrogen is consumed by soil organisms and/or plants the soil returns to pre-nitrate-nitrogen "normal" and the population of organisms returns to "normal." "Organic" forms of fertilizer have the same effect on the soil, however they normally breakdown more slowly. "Organic" sources of nitrogen, for example, have to be broken down by soil organisms to nitrate-nitrogen before they can be used by plants for growth. Plants can use only inorganic sources of nitrogen. Just because something comes from a "natural" source does not mean that it is better or worse than "conventional" sources. Some of the most toxic compounds known to man come from "natural" sources i.e., botulin toxin, nicotine and the venom of a South American sea snake. Bagged fertilizes are mined in the cases of phosphorous and potassium. Nitrate and ammonium nitrogen comes from natural gas and air (which is 78% nitrogen gas) that are combined and processed under high temperatures and pressure. These are all natural products combined to make an "artificial" product.

To be continued next month...