Good question. I've noticed in my area that grass just doesn't do well under a pine tree. I'm talking the plain old tall pines with only a handful of limbs way up high that can't provide enough shade to cause problems with grass. I'm thinking the needles have to be causing the problem. Maybe someone can give us an explanation.

Well, these needles are somewhat acidic. Most turf grass species are adapted towards a more or less neutral soil pH. so there's that, although in most cases I'm aware of, the soils buffering capacity will rather quickly neutralize any acidification provided by the needles laying there. To some extent, this depends on the pH range of the soil where you are. I'd generally recommend to go ahead and mulch them in. Another option would be to purposely collect them to be used as mulch around plants that appreciate a minor boost in acidity. It's not as strong as some folks think, again because of this buffering capacity, but a modest change in pH can be had.

+oM

Initially, pine needles are a little acidic, but not particularly so. Once they decay (and that's kind of slow), the resulting humic matter is in the pH 6-7 range. Ultimately, it tends toward 7.

Like a lot of other things, the myth that they're especially acid is just that--a myth. Eventually they'll tend toward neutral like any other organic matter.

Mulch them if you want, or rake them if you prefer as they can be a little difficult to mulch mow to invisibility.

Thanks. As morph mentioned, they didn't mulch very well, so I guess I'll stick to the strategy I executed yesterday - a very fast raking to get the bulk of them off the lawn. I'm relieved to know I don't need to worry about acidity...but I think I'll still chop off some branches because those needles are a PIA.

In the fall before the needles fall cut you lawn on the short side. You can then "rake" your pine needles with a leaf blower.

I have been doing this for years with success. Don't worry about those needles that have worked them down into the grass, as said above they will decompose.

As for the needles that you rake up, they make great mulch for the flower beds. I have been known to exaggerate my lot line to get more needles from the other side. DON"T use them to make mulch volcanoes around your trees. It is bad for the tree.

Just remember the leaf blower is the tool of choice for most non digging or cutting the grass task.