I recently removed old roots, weeds and grass from a small area in front of our house. I had some leftover mushroom compost, so I built up some areas to make the entire area level, but now it seems that dead pine needles from a neighbouring tree are falling onto the area I just seeded. Will the pine needles not allow the seeds to germinate? Is there anything I can do?
The pine needles shouldn't really impede the growth of the grass unless they wind up covering the ground quite thick. It is common to put straw or other cover on grass seed to protect it from too much sun, animals, erosion, etc.
BUT if those "old roots" you removed were actually from said pine tree, this could cause the pine tree to drop a lot of needles that could, in theory, smother the seed.
Of very low concern - at least in most scenarios - is the pH change that could occur from the pine needles. I would expect the seed to establish before this could become an issue, though.