Book 29, Question 116
What are peat moss and coir, and why are they in potting mix?
Both hold water and keep potting mix fluffy.
Peat moss is made from partly decayed moss harvested from bogs, and it forms very slowly, so many gardeners worry about digging up bogs. Coir is made from coconut husks, a leftover product. Both soak up water like a sponge. Many potting mixes now use less peat and more coir or compost.