Would Pine Needles Be Good Mulch?

If you have toured some of the carefully cultivated gardens in the southern United States, you have probably seen pine needles used as mulch. Organic mulches, such as pine needles, improve the quality of the soil, control weed growth, conserve moisture and moderate temperature changes.

Benefits

Pine needles (also known as "pine straw") are particularly effective when applied as mulch around acid-loving plants, such as rhododendrons, azaleas and roses. According to the Cornell University Department of Horticulture, pine needles break down over time, lowering the pH of the soil to a more acidic level while at the same time adding organic matter. Pine needles also have an attractive dark brown color that improves the appearance of the garden.

Function

Pine needles form a light mat that prevents soil compaction and crusting and allows air and water to penetrate to the soil below while acting as a barrier to the growth of weeds. The mat also insulates the soil from extreme temperature changes in the heat of summer and the cold of winter.

Disadvantages

Because pine needles are so light and airy, a deeper layer (as much as 4 to 5 inches) may be required to keep the weeds in check. When pine needles are purchased in garden stores, they should be clean, but gathered needles may contain weed seeds that can sprout the next growing season and actually cause more weed problems than they prevent.

References

• Cornell University: Mulches for Landscaping
• Texas A&M University: Pine Straw as a Ground Cover Mulch
• MSU Cares: Vegetable Gardening in Mississippi