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Thursday, June 11, 2020

Pine Needle Mulch by Jon K. Fitzgerald

Jon K. Fitzgerald
Mulching your landscape with pine needles.



Jon K. Fitzgerald
Raking pine needles, or pine straw, from my lawn is my least favorite thing to do in the garden. It is very slow going, tiring to the shoulders, and takes a lot of patience. But as of a few years ago, I've now got a higher purpose for this daunting task. Free mulch!

The source for my free mulch is eight mature Austrian Pine trees, (Pinus nigra). In some areas it is known as European Black Pine. The needles live on these trees for about three years followed by a seasonal needle drop of the older ones in late summer and fall. The needles themselves, on the tree or on the ground, have a pH of 3.2 - 3.8 and this fact has led to some myths and misunderstandings about the acidic nature of pine needles and their effect on the soil when used as a mulch.
Jon K. Fitzgerald
In a search for scientific answers, my quest first took me to the University of New Hampshire: I learned that pine needles do not acidify garden soil. Then a visit to Oregon State University: I was informed that as the needles break down the decomposing organisms gradually neutralize the needles so there is no harm using it as a mulch. And then back to our home base, Colorado State University: It was confirmed that there is not enough measurable pH change in the soil when using pine needles as a mulch. Mission accomplished!

We already understand that mulch is beneficial for our soil and plants. It helps retain moisture, it suppresses weed development, warms the soil, decomposes into organic matter adding nutrients and makes the soils more tillable, and helps with compaction and erosion.

Pine needle mulch. The benefits are many: it is light and fluffy and does not compact much as it decomposes; it decomposes slower than wood bark or chips so it lasts longer; the needles interlock and resists blowing away in the wind. It is airy, breathes, and readily allows water to seep through to the soil. It looks attractive in the landscape and garden and it can be free if you have pine trees! I have not needed to purchase pine straw but noticed its availability at big box stores.
Jon K. Fitzgerald
Raking has not gotten any easier, but my reward is an annual and convenient supply of pine needle mulch to replenish my landscape and garden beds.

Additional Information:  CSU-PineMulchMyths