Question
I live in western washington, want a good looking lawn, as dark green as possible. What would be the best seed blend for this.  

Answer
I think a good kentucky bluegrass lawn would have the best chance of being dark green. In many instances, however, the selection of the actual cultivar (named varity) is more important than the actual grass type when it comes to color. I recommend talking to a local garden center and have them advise which of the KGB blends are dark green. Normally seed mixes are sold as light, medium or dark green.

Each grass types are seperated into individual cultivars which will each exhibit individual performance characteristics, such as winter color, disease resistance, color variation etc. These cultivars are then named.

Sometimes, cultivars are grouped into 'types' of one or more cultivars which exhibit similar performance characteristics. e.g. a type may consist of two cultivars which both have good winter color, are low growing, green up early in spring, and which has good disease resistance with wide leaved and medium green color.

If you can find it, the KBG cultivar called "midnight" is known to have a very (very) dark green, compact, dwarf growth habit with above average resistance to powdery mildew. It is a consistent leader in turf trials.

'Midnight' has also been given name to a type (group) of KGB cultivars with these characteristics. The best performance you get, if you have the garden center order a blend of cultivars of the "Midnight" types (consists of cultivars such as "Midnight", "J-1838", etc).

In general, if you go through a garden center and read the lable, a a pre-blended bag mixture containing cultivars such as midnight, ascot, alpine, and noblesse you can usually be assured that it should be dark green.

If you are looking for straight cultivars, try seedland.com
They carry midnight.