A great medium for starting seeds or propagating cuttings, coir is a biodegradable peat alternative made from coconut husk fibers, a renewable by-product of the coconut harvest.
These compressed pellets are particularly convenient because you don't need soil or pots. Just drop the pellet into warm water and it expands to several times its original 1 3/4" × 3/8" size, making it ready for planting immediately. A fine mesh covering holds it all together.
When the plants have grown to size, you can drop the whole thing directly into the ground or into a planter.