Which straw is best? There are those out there who say the best straw to build with is rice straw because it is very strong and has a high silicone content which makes it hard to burn. Others say flax straw is a great idea because it is really rot resistant. Some suggest wheat is best because it can be long cut straw in tight bales and at the same time is easy on your tools. The answer, as far as I am concerned, is all of the above and none of the above.
For me, the best straw to use is the straw that is local to you. Consider that you are building an energy efficient home. Does it make sense to truck straw across the country to your site because rice is better than wheat or vice versa? I don’t think so. As long as the bales are tight, uniform, dry, and of general high quality, I think you can use what is closest to your site. In fact, I even know of a guy who built a house using bales of old, compressed cereal boxes!
Yup, even that worked and his material was basically free since the recycling center (who did all the binding and compacting) was happy to give it away instead of process it. They saved money and he got free building materials (small transport fees did apply of course). So use what is high quality and close to you and you will be happy in the end.