Sphagnum - Loose or Packed Tight?

[Dollythehun]

I gather, from reading bits and pieces of this long thread, that you are mostly talking about catts. I use Roberta's method for most every other type of orchid. I have very good success mixing a touch of any bark, cut up corks etc. with my spagh. I wait to water until the top is crusty, then I drizzle water. If you pour it on, you'll be wiping the floor. For my oncids and phals, I will water from below about half the time. I have failures but, never from root rot. Also my 2c.

[Jmoney]

Thanks Roberta! I have been using sphagnum for years but in the beginning it was very much a love/hate. (back then it was mostly phrags). Plants really perked up and put on a growth spurt, but after a year or so invariably they would decline. They were potted "loose" and when I finally got around to repotting it was a slimy mess with dead roots. I chalked it up to rapid breakdown of the moss and needing to repot earlier.

under my conditions the tight packing method produces totally different results. Not saying one is better than the other, and clearly depends on one's growing conditions and watering habits, but just saying the two are night and day in terms of properties...

[Fairorchids]

I have also purchased from both OV & Christoffersen, and admire their results with the tightly packed spaghnum. Having read only the tail end of this thread, it appears that most are talking about large/mature Cattleyas. Size is an important consideration too.

I use spaghnum (coarsely chopped), but only for seedling plants up to 3" pot size, and mixed with about 1/3 seedling size bark & charcoal. That mix is only used in 3" plastic pots with multiple slits in the sides; I pack it fingertip firm, but not hard. This ensures a 3-4 day period of fairly consistent moisture + some air flow.

For 5" & larger I use clay pots, with granular mix II (Catt size bark/charcoal & super coarse perlite in 2:1:1 ratio).

For 3.1/2" to 4.1/2" sizes I use clay pots, with granular mix I (1/2 the bark is seedling size).

For a few larger plants, I use baskets with Aliflor (Leca) clay nuggets.

With this size based selection, I can water everything in the greenhouse at the same schedule (twice a week in winter, three times a week in summer).

My dad, who was old school, used exclusively clay pots, always with spaghnum/bark mix (3:1) and tamped down as hard as he could with a potting stock. Plants grew fine, but it made watering a more cumbersome process, as you had to water pots of different sizes at different rates.

[estación seca]

I heard a lecture on growing Phals in tightly packed moss. I took notes but haven't written them up yet. The gist is the moss is never completely soaked. When the top is crisp just run water over it for one second. That water diffuses through the entire moss ball, leaving it well aerated.

At repotting the moss is dampened but not soaked the night before. It should be flexible, not crisp, yet not feel wet. Wrap it around the roots to form a large ball and stuff it tightly into the pot. That person uses transparent plastic pots so she can see roots. Leave a generous gap below the pot rim for water.

I don't use moss because S/H works well for me. But without S/H I would use moss.

When I receive a new plant in moss I keep it until repotting at the appropriate time. Catts, Catasetinae and Oncidiums use water much faster than Phals. I do soak the moss for those. Note my growing area is warm to hot much of the year.

Alan Koch lectured he uses 7 different potting mixes for different plants to permit watering his hundreds of thousands of plants once a week. Moss is one such mix. He does soak it. I have bought Catts from him potted in moss.

[ozymand1as]

That is similar to my experience.

The best part about watering sphagnum moss is that moss weighs almost nothing when dry. That makes it incredibly easy to tell exactly how much water is in the pot. Much more so than bark.

Unlike bark, firmly packed moss moss wicks moisture so well that surface dryness usually indicates the rest of the moss is almost dry as well.

I don't even feel the need to use clear pots with moss, although it is still nice to have them.

[Roberta]

I don't have the problem, but know others who do have allergic reaction to sphagnum. There are spores, which are allergens. Certainly, nobody should ever work with the stuff dry... having it moist will reduce what goes airborne. Another common potting material that can be an issue - perlite (sponge rock). It crushes to a fine powder, and it's silica... something that you don't want in your lungs. Again, spraying with water can reduce the dust, but also stayi8ng upwind and wearing a mask are good practices with it.

[estación seca]

Almost no plants require one specific growing medium. You can find other media that don't affect your allergies. Most epiphytes can be grown in non-organic media like pumice, LECA, scoria/cinders or pebbles.

[isurus79]

Originally Posted by estación seca

Almost no plants require one specific growing medium. You can find other media that don't affect your allergies. Most epiphytes can be grown in non-organic media like pumice, LECA, scoria/cinders or pebbles.

This is a good point!