Bamboo is only suitable for long-term use when it has been properly dried. The high water content of bamboo allows it to rot, host fungi and be eaten by insects if it is not first cured. Three common methods of drying bamboo are fire drying, air drying and -- counterintuitively -- soaking in water.
Regardless of which drying method is used, the bamboo should be properly harvested so that it doesn't split during the drying process. Only cut down bamboo shoots that have been growing for three to five years. It takes this long for the plant to fully harden. Once hardened, the bamboo will shrink less when dried, and it will not be as easy for insects to bore into the plant. Cut in the fall and winter while the sap is not moving to decrease the chances that the bamboo will split and crack. Any cutting tool can be used, but cut the bamboo as near to a node as possible, where it is the hardest, to prevent crushing or splitting during the cut.
Air drying is the most common method because it is simple and cost-effective. Cut the bamboo shoots and store the pieces vertically without removing any of the leaves or branches. The large surface area of the leaves and branches gives more area for evaporation of moisture. Store the vertical stacks of bamboo in a cool and shady area; this allows evaporation to occur slowly enough that cracks and splits do not form. This method takes several weeks, and its success depends on the weather not getting too hot and drying out the bamboo too quickly.
Bamboo has natural resins, or oils, that can help preserve the bamboo. Heat sections of newly cut bamboo over a fire or other heat source that will heat it to 120 degrees Celsius (250 degrees Fahrenheit), taking care that it doesn't catch on fire. The bamboo's resin will bead on the surface of the heated section where it can be wiped away with a cloth. Bringing resins to the surface helps to seal and preserve the surface while removing internal barriers to moisture removal. Heat one section at a time, because the resins will quickly dry when removed from the heat source. Fire drying is the most reliable method for not cracking or splitting the bamboo.
Soaking in Water
Another method for drying bamboo is to first soak the shoots in water. Completely submerge the bamboo in water and soak for 12 weeks to completely saturate the plants, then place the bamboo in a sunny area to dry. Soaking protects the bamboo from insects as it dries, as it leaches out starches that the insects would normally eat. It also saturates the plant with water, evening out the moisture content, so, as the bamboo dries, the water evaporates evenly and slowly, which can prevent cracking and splitting even in hotter weather.
Joshua Bush has been writing from Charlottesville, Va., since 2006, specializing in science and culture. He has authored several articles in peer-reviewed science journals in the field of tissue engineering. Bush holds a Ph.D. in chemical engineering from Texas A&M University.