Here are some other facts to consider:

• Pine straw in itself is slightly acidic at 6.0 - 6.5.
• Normal rain water tests at 5.6.
• So why hasn't the soil at a pH of 7.0 in the salvia bed become more acid?
• Soil is not a static medium. Its components react with one another. In the case of rain water and pine straw, those interactions have a neutralizing effect on their initial acidity.
• Research by others, more carefully and scientifically done than my experiment with the salvia bed, shows both small increases and small decreases in soil pH from using various mulches such as oak leaves, pine straw, and shredded cedar. However, the changes were so minuscule that they were totally insignificant, and there was no negative impact on plant health.

nother issue sometimes raised in the pine-straw-as-mulch debate is that of terpenes in the needles. Terpenes are chemical molecules said to retard germination and new growth. Since I don't mulch seed beds and use pine straw only in established beds, retardation of germination is a good thing. It helps to keep weed seeds from germinating.

The terpene effect turns out to be short-lived. Terpenes dissolve readily in water and dissipate into the air, leaving behind only trace amounts that may discourage germination but certainly don't harm established plants. By the time pine needles are brown and dry, most of the terpenes have evaporated. Once that wonderful pine fragrance has gone out of the needles, so have the terpenes, the source of that fragrance.

So why is pine straw a good mulch? Let me count the ways:

1. It lasts a long time. Pine straw doesn't float and wash away. It breaks down more slowly, so it doesn't need to be reapplied as often as other mulches.
2. It's lightweight, lighter per cubic foot than most other mulches. The bales are easy to carry and offer more coverage for the equivalent weight of other mulches.
3. It's sustainable. No trees are harvested to produce it.
4. It promotes soil health. The soil breathes better, doesn't compact, and allows for better water infiltration with pine straw than with other mulches.
5. It promotes plant health. Its decomposition adds organic material and nutrients to be taken up by plants.
6. Its uniform color and fine texture is visually appealing.
7. It doesn't attract termites.
8. It's easy to apply.
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