We use coconut
husk fiber in a variety of ways when growing plants (primarily orchids).
We use to it line baskets; it keeps orchids mixes and soils in place.
We use it as a pad to retain moisture on plaques when we mount
orchids. We also use it alone as an orchid medium for specific orchids.
It retains a bit of water, re-hydrates easily and algae is very slow to
grow on it.
It is also great in cages if you have birds or reptiles.