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Soil Issues/Acidic soil under pines vs oaks

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Expert: James L. Crowder - 5/5/2009


Question
It is my understanding that the fallen needles (leaves) of a pine tree are in the pH range of 6.2 and the leaves from Oaks in the range of 4.3.  how is it that the soil under pines is more acidic than under Oaks?  Is it a chemical reaction of the breakdown of the needles that causes the pH to be lower while the Oak leaves do not decompose as readily and become widely dispersed with little affect on the soil immediately under the Oaks?  Where am I going wrong here?

Answer
Hi Michael, It's not as simple as it sounds.  The pH of the foliage is dependant on the pH of the soil and the type of plant.  Generally though, the more acidic the soil, the more acidic the foliage. Oaks have adapted to excel in different soils than pines but both will survive in less than optimum pH and soil type.  The truth is, decomposed pine needles or leaves have virtually no effect on the soil's pH.  Jim

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James L. Crowder

Expertise

I can answer questions about soils, soil amendments, drainage and proper planting. I can answer questions about insects and diseases, weed control, etc. I have extensive background in homeowner labeled pesticides (insecticides, herbicides, fungicides, etc.) and their proper use. I can also answer questions about the growing requirements of specific plants.

Experience

I have 40 years experience in the lawn and garden business split fairly evenly between the retail nursery business and wholesale distribution of consumer lawn and garden products. From 1990 to 2000 I co-hosted a weekly call-in talk radio program in Memphis, TN.

Organizations
Garden Writers Association

Publications
Green Thumb Magazine - out of print

Education/Credentials
40 years of learning everday.

Awards and Honors
Past president of the Memphis Horticultural Society. Past president of the Memphis Bonsai Society. Memphis Horticultural Society 2008 Horticultural Excellence Award

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