Sphagnum - Loose or Packed Tight?

[SouthPark]

Originally Posted by Ray

I have never understood the "physics" or "mechanics", or whatever you want to call it, of tightly packed sphagnum. (Those of you who know me well must understand my consternation at that!).

Absolutely. It is interesting that some situations appear very counter intuitive. I often wondered about that too in the past. I recall once reading somewhere - that the firmly packed spaghnum itself can behave on-the-whole a big wick.

If air-circulation is very good, then the water in the tightly packed spaghnum can disperse - wicked around through the mass. And if air circulation is good around the plant and also through maybe many big holes in the pot at the bottom, then a slow flow or movement of water and air etc can be maintained.

The grower must provide a suitable amount of water during the watering, and must have a suitable frequency of watering. They have to sort this out, or work it out for themselves under their own growing conditions. Too much water will definitely lead to saturation, and undesirable things that follow from that.

Too little water, and the water might not get down into the depths (middle and lower part) of the pot.

Catasetum nursery growers use this tight spaghnum method. Some do it for Cattleya - seedlings and all.

The tightly packed spaghnum 'system' is a system. How it all works and how it is controlled is often up to the grower. If the spaghnum is primed (pre-wetted), then one way to keep this system under control is to periodically add maybe suitable amount of water, to keep the system moist. Good air circulation is beneficial as always. An important thing is to know roughly what might be going on inside at the different layers or levels of the pot. This applies to any kind of growing media.

For myself, I've only recently begun to grow catasetum in scoria - 5 mm average diameter scoria. I haven't grown for long enough yet in this media. My current method with my catasetum is fairly tightly packed scoria, with big scoria rocks piled below the spaghnum mass, and around the sides of the spaghnum mass - all in a pot. So the spaghnum is surrounded by scoria. I don't know if it's necessary to do this, but the catasetum type plants have no problem with it.

I just prefer inorganic - scoria.