Did you have any idea that it is possible to purchase concrete made from hemp ?

There is a company in the UK that has a product called Hemcrete© using hemp that is grown and harvested in the UK.

There is also now a US company supplying hempcrete: Hemp Technologies LLC.

Since Hemcrete© is a bio-composite building material, it actually locks up around 100kg of CO2 per square meter of wall. That doesn't happen with normal concrete, since it is basically made of sand, gravel, and stone.
Meanwhile, up to 200kg of CO2 is emitted in the production of each square meter of walling of houses. Which would be about 400 tonnes of CO2 emitted to produce the walls of a typical house!
And you can only imagine the insulation benefits of using hempcrete walls over standard building materials.

My opinion: you guessed it! Go green! Go Hemp !

Here is some more information on the benefits of using Hempcrete:
http://www.natural-environment.com/blog/2008/02/01/you-say-hemcrete-i-say-hempcrete/