Hempcrete or hemplime is bio-composite material. It is a mixture of hemp hurds (shives) and lime which is used as a material for construction and insulation. Hempcrete walls are fireproof, transmit humidity, resist mold, and have excellent acoustic performance. Using hempcrete is a great natural way to build a home!
Producing and using hempcrete is also eco-friendly! One acre of hemp provides as much paper as 4.1 acres of trees. On top of that, it takes about 4 months for a hemp plant to be fully grown, and in some areas of the US you can grow more than one crop a year. Also, like all plants do, hemp absorbs CO2 from the atmosphere as it grows, retaining the carbon and releasing the oxygen.
But if you plan to build a hempcrete house in the US, you'll need a permit for the use of hemp in building.