General Tips (Northwest US)
Oregon and Washington are split in half by the Cascade Mountain range. Rainfall is most definitely impacted by the combination of the ocean and the mountains. Soils tend to be neutral to slightly alkaline, but saline and sodic soils are generally not a problem. Cool season grasses rule here, in fact a large portion of the world’s grass seed production is found in this region.
West of the Cascades, the climate is modified by the Pacific Ocean providing sometimes very high precipitation in the form or rain and snow October through April. Summers tend to be mild in temperature with intermittent rainfalls likely. Because of the higher rainfall, problems with moss, bentgrass and Poa annua invasion of lawns is not that uncommon. Red thread, pink snow mold, and rust can be found. Insect pest such as cranefly and cranberry girdler can cause significant turf damage as well.
East of the Cascades the rainfall drops off significantly and winters can be markedly cooler. Summers are drier and warmer. Supplemental irrigation is needed to prevent lawns from going into summer dormancy. Lawn management issues may include water, possibly some alkaline soils, some insect activity like cranberry girdler, and potentially some disease activity like necrotic ring spot.