In Part 1 I started this article about all the different types of medium that is used to repot orchids.

For those of you that missed that article you can go back and read it.

There are still many types of medium to talk about so lets get started.

These media are starting to pick up in popularity.

They hold moisture up to seven times its weight and will last for years.
These materials are also very porous and easy to handle.

The coconut fiber is excellent for lining baskets and for use with orchids that like to be kept moist such as Paphiopedilums.

The husk chips are 1/4" to 1/2" in size and works very well in pots.
It has been used for years in Holland for Cymbidiums and Phalaenopsis.

The price for these media is very reasonable at this time. You can purchase it for around $1.00 a pound.

NOTE
As you certainly know coconut palms often grow at "sandy" seashore beaches. Those "sands" consist more often than not from pieces of mollusk shells, coral skeletons and the like rich in calcium and saturated with salts dissolved in the sea water.

May as sound as unbelievable as it is granted, yet there are coconut husk piles at beaches for example in Sri Lanka, which were piled up documentably centurieas ago - and became conserved by sea salts perhaps for millenia to come.

Needless to say, husks or fiber of such origin used without cautionary measures can be lethal to orchids.

Fresh husks and fiber "straight from the palms" contains high amounts of fermentable compounds and the microbial fermentation processes taking place around the roots of potted orchids may be lethal again.

Actively growing root tips of orchids are extremely delicate strutures: in fact in many orchids root tips are the most sensitivle structures of the whole plant.

Roots attached to a firm support or buried im potting media follow moisture and nutrient gradients. Although this explanation is far from being academically exact, yet just as you cannot feel the taste of excessively oversalted food, the root tips are experiencing somewhat similar problems in overly salty environments.

Root tips become stunted or stop growing at all, which means cessation of the whole root growth as such. Nutrient uptake of the plant may get badly unbalanced no matter what kind of fertilizing regime is used - and so on.

Therefore, make sure you buy coconut produts from a reliable source.

In case of doubt soak the material in large quantities of soft water (pure rainwater, melted snow or deionized water) changed several times over weeks before using it in potting mixes.

If you own or have access to a conductivity meter, check the conductivity of the leachate and do not use the material if the conductivity exceeds 600 mho.

The lower the better - 400 mho is just great, such material will be all right for your orchids for years.

Rock wool is a medium produced by spinning volcanic basalt rock in blast furnaces.
It has been used for years as an insulation in homes and buildings. Oil that is in the insulation type material is removed when the product is used for horticulture.

It can be mixed with bark or used alone.

This product lasts virtually forever and has very few problems with insects because it does not break down and decay when used alone.

It can be purchased in cubes, mats and pellets.
Rock wool tends to pack tight so many growers will mix perlite or tree fern fiber with it to maintain an airy consistancy.