Coir peat is made from the outer husk of the coconut. It absorbs moisture and is great in sandy soils. It is also a waste product that is being put to good use. It also comes from struggling economies like Sri Lanka, that need the economic help. They soak it in water to remove excess salts and then dry it and bail it extremely compacted to efficiently freight.

You simply add water, break it up a bit once it softens, and then it is ready to use. It makes a beautiful mulch on top of the garden, or can be incorporated into the soil like I have done with this fern.

I shoveled the coir it into the hole, planted the fern and put more coir all around it. That should do the trick.

http://gardenworld.com.au/2013/01/10/planting-in-the-fernery-coin-spotted-tree-fern/