Bluegrass music is an offshoot of the country and western musical genre. As with country music, bluegrass has its foundation in the music of Ireland, Scotland and England. If bluegrass is centered on one area of the USA, it is Appalachia. The people are of Irish and Scottish descent and in their music instrumental virtuosity is not a poor relation of singing. In most forms of popular music the instruments back up the vocalist, but in bluegrass the vocals and the instruments are all just members of the team. In a bluegrass band everybody is expected to take a solo just as they do in a jazz band. The instruments associated with bluegrass music are acoustic guitar, banjo, fiddle and bass.
The main thing to remember if you want to learn to play bluegrass scales is to learn some tunes. That is what music is made of. The scales are just the foundation of melodies and you need to be able to break out of the confinement of your scale as soon as possible. The other thing learning tunes is good for is developing right hand speed. As you can tell from listening to bluegrass music, speed flatpicking is essential.
If you are interested in learning bluegrass music and you would like to start by learning scales, start with the major scales in the open position. Do not bother with going up the neck of the guitar yet because learning your scales in the open position is crucial for playing bluegrass solos. Learn the scale in the key of G first, then C, D, F, A and E. Learn the keys one at a time so that you are comfortable with one before you go onto the next key. As with all musical learning, the more work you put into it at the beginning, the greater the rewards and the quicker your progress.
When you sit down each day to practice your scales, spend five or ten minutes going up and down the scale alternately. Then experiment a little. Try playing the scale by skipping some notes or playing the notes randomly. You need to become very familiar with the major scale because bluegrass solos rely on major keys. To get further into bluegrass guitar scales, find examples of the major pentatonic and the major diatonic scale.
Another basic scale that is important in bluegrass, blues, country and rock music is the minor pentatonic scale. It has five notes, should be learned in all positions on the guitar neck in all keys, and has been used for lead solos by every guitar player known to man. It is also popularly known as the blues scale. If you do not know much about modes, do an internet search to get some idea of the difference between a scale and a mode. If you have trouble understanding the theory, do not worry, just try playing.
The mixolydian mode is a good “scale” to practice on also:
To get more in-depth knowledge of bluegrass guitar scales, some great bluegrass guitar players to listen to are Vassar Clements, Doc Watson, Darol Anger, Clarence White, Norman Blake and Sam Bush.