The cold hardiness of Douglas firs depends on the type of seedling, so check with the local nursery for ones appropriate to your area. Seedlings whose parents are from the Pacific coast are a bit less hardy than those whose parents are from the Rocky Mountains.
Douglas firs, like most trees, need sun. However, they will accept light shade. They tolerate most soil types except clay. While they appreciate atmospheric moisture, they do not like soggy soil. They prefer moist well-drained soil which is slightly acid (pH 6.0 to 6.5). Choose a site which gives Douglas firs lots of room to grow, but which is not exposed to high winds. The shallow root system that sometimes causes Douglas firs to blow over in heavy winds, also insures that they transplant easily.
