Question
Hello. I recently moved to the country with a large yard underneath 90% Ponderosa Pine and 10% Oaks in Northern California (Twain) and would like to know if the bed of needles should be raked up to foster native grasses? I have heard somewhere that coniferous pine needles inhibite ground growth. Is there anything to this? I also heard not to tamper with the ground needle cover as it removes a protective layer of ground. My soil is mostly sandy (Feather River) riverside soils. Topsoil is minimal. Please render your opinion on this. I am getting two sides to this problem. Thanks. Larry W.  

Answer
Pine needles do not prevent grasses from growing and they actually provide a matural mulch. However, very large quantities can smoother small grass plants. Normal shredding is not a problem, but I would no go dumping inches of pine needles on new young grass plants.

Under mature pines grass seldom grow adequately due to competition for particularily sun and moisture. the tree shades the sun and the large roots compete for water. in addition the soil is often very compacted by the root activity. This, and not the pine needles, are responsible for grass death.

It may still not be possible to grow grass right around the pine trees. Normally a 5-8 feet wide "mulch ring" can be created around trees and grass then grown between trees but not right next to them/under them.

Grass may still not grow adequately if getting a lot of shade, however.