A culm block and a method of manufacture are disclosed. The culm block comprises a plurality of straw stalks forming a first rigid wall and a second rigid wall as a result of an application of heat and pressure to the same and the inherent bonding agent found in the straw stalks. Preferably, the culm block further comprises a plurality of through-holes for receiving structural reinforcements or otherwise and a restraining device wrapped about the block for added structural support.