Depends upon how long you will keep them in containers before putting them in the ground.
I would think you could use smaller than 5 gallon containers quite effectively.
Use smaller container before sexing, then put the girls in larger containers until they are planted in your beds.
Most states provide very inexpensive soil testing through local cooperative extension offices.
In Florida it is only $7 per soil test.
Unfortunately, It appears that CA does not provide soil testing services… ?
Here is some info regarding agricultural cooperative extension offices.