Question: My neighbors haul away their pine needles, yet I see bales of pine straw for sale as mulch at the garden center. Are pine needles a smart choice for mulching if your garden does not have pine trees in it? Will the pine needles change the pH level of the soil?
Answer: For mulching and building garden paths, I love the needles of white pine (Pinus strobus). They feel soft enough to walk on with your bare feet. They do a remarkable job at weed suppression and water retention. Also, they can be easily crumbled into smaller pieces for mulching containers. The needles interlock, so they don’t wash away, making them ideal on sloped garden areas. They also tend to break down more slowly than other natural mulch options like deciduous leaves. However, they stay loose enough to let water and air penetrate the soil, as opposed to wood-chip mulch, which sometimes creates an impenetrable crust over time.
Despite all the positive traits of pine straw, this superb organic mulching material still has a bad reputation, likely linked to pH. People fear the needles will affect their soil's pH, but in the big picture the amount of acidity released from fallen brown needles is negligible. Even green needles, which are seldom used as mulch, have a low pH level that is quickly leached away with rain and exposure to the elements. So go ahead—mulch with pine straw and worry not.
