Forget Smoking It, Hemp Could Replace Concrete

The most sustainable building material is not concrete or steel — it is fast-growing hemp. Hemp structures date to Roman times. A hemp mortar bridge was constructed in the sixth century, when France was still Gaul. A wave of builders and botanists are working to renew this market. Mixing hemp’s woody fibers with lime produces a natural, light concrete that retains thermal mass and is highly insulating. No pests, no mold, good acoustics, low humidity, no pesticide. It grows from seed to harvest in about four months. (Click on title for full story.)