The vegan or environmentally-conscious knitter should be familiar with bamboo yarn. Since bamboo, unlike cotton, grows again from its own roots, it requires less care, attention, and resources to grow, making it a more sustainable option. In addition, since it's a fully vegan fiber, those with an aversion to animal products will find that bamboo yarn, unlike silk or wool, is a strong alternative. There are some bamboo yarn patterns that specifically call for this kind of fiber, but even if a…