I live in an area with a lot of pine needles and they seem to work great as a free mulch. I’ve heard some sources say that pine needles they have high acidity so they should be avoided in the garden. Other sources say once they’ve dried out and turned brown and brittle the acidity is drastically reduced and they will only leach a negligible amount into the soil so they are fine to use. Anyone have any experience/advice using pine needles such as I have here?
by carlakacich
6 Comments
Pine needles themselves are high acidic, that’s true. But pine trees don’t acidify soil, they just prefer high acidic soil themselves. After some research, including reading scholarly articles, I have concluded that the idea that pine needles acidify the soil is a myth.
Fermented pine needles do not affect soil pH. Unfermented pine needles may temporarily lower soil pH during decomposition, but the impact is minimal and temporary and they decompose extremely slowly. Pine needles make excellent mulch and can be used with confidence in most situations.
Although I have never used pine needles as mulch, but I often mix them with other soil . So far, I have not observed any adverse effects.
Here is a research “Effect of pine bark, pine straw and red oak amendments on pH of potting medium”
DOI:10.37855/jah.2010.v12i02.22
I’ll highlight their conclusion for you
https://preview.redd.it/kk0xwgxrkz5d1.jpeg?width=868&format=pjpg&auto=webp&s=a8b5549084e53d3159bef3f126e185c1fc0d5710
The comment above is correct. The great pearl clutching and wringing of hands over acidic things being used as mulch are way way overblown.
I’d also like to throw out that most pants prefer slightly acidic soil over slightly alkaline soil, and some plants(like blueberries) positively crave the acid. So mulch on! I wish I had a pine tree to give me free mulch. I have to purchase my mulch, and it’s not nearly as attractive looking.
I don’t have anything to add as an answer but I have a question. Do the rock strawberries help keep the birds away by them learning that pecking them will hurt?
I use pine needles exclusively to mulch around all my raspberries and blueberries. I put it as thick as I can. At least 3 or 4 in. Does an awesome job of keeping most of the weeds from growing, it breaks down very slowly, keeps moisture locked in at the soil level. It’s really an amazing mulch. And as others have noted the idea that it will significantly acidify the soil is a myth, especially if you’ve picked up the pine needles after they’ve been laying on the ground for a couple weeks or more.
I prefer pine needle mulch but it’s a little harder to find sometimes
It’s totally fine