Combining Orchiata with NZ Sphagnum Moss

[HiOrcDen]

Some of the Orchids I have purchased came in pots with a combination of sphagnum moss and orchid bark.

Some of these orchids just have moss around the base of the leaves at the surface, towards the center. So I am guessing this is to keep emerging surface roots moist, is this correct? With these, I just water around on the bark, at an angle to get towards the center underneath. Though from my experience, roots which emerge above the substrate do not need to be kept moist, especially if green.

Some orchids I got seem to be in kind of a chaotic mix of a mass of sphagnum moss with bark chips, in uneven proportions. I try to water in a similar manner as the first instance, though I'd really like to repot them in a more orderly fashion.

So the 3rd instance is something which I actually like. And that is a smaller amount of moss mixed in with the bark substrate. I like the way the sphagnum keeps the chips in a solid mass. Is this okay for all species, or only certain species?

There are two more instances I would like to ask about.

One is a pretty big Brassavola Digbyana. I bought it over a month ago and put in sphagnum moss. It seems to have done okay til tonight, and I'm starting to see a bit of darkening. I would like to switch it to orchiata, since the plant is too big for moss, I think, especially in a standard pot. Should I put a bit of moss in with the orchiata when I repot?

Also, should I put a bit of pumice, for some aeration... should the pumice be somewhat crushed/broken up a bit.

Also, my big Angraecum, which came in just under a 1 gallon pot, I have repotted to a 1.5 gallon, standard pot (no slots) It came in 100% small chip bark. However, since it's now in such a big pot, when I repot to small chip orchiata, again, should I add some pumice and/or perlite for extra aeration?

I'd like to repot the Digbyana tonight... so I'd really like a suggestion of whether I should use a bit of moss (since its been in 100% moss for a month) as well as perhaps pumice or perlite!

[Burgos]

I use sphagnum to cover some of my pots for two main raisons:

First, it keeps the substrate a little more protected from sunlight, dry winds and dessication. It stimulates new root tips, which may otherwise die if they don't reach a cool humid surface in a short time. It's easy to remove when winter comes or to replace if it really breaks down.

It is also helpful when repotting, as it holds the plant and bark chips in place.

Then, I have recently been adding it in different proportions to some of my orchid pots which are more airy, so that roots can decide whether they go for the side where there is more sphagnum or to the other side. My desires japonica has quite improved since I repotted it in a higher proportion of sphagnum.

[Ray]

Originally Posted by HiOrcDen

So the 3rd instance is something which I actually like. And that is a smaller amount of moss mixed in with the bark substrate. I like the way the sphagnum keeps the chips in a solid mass. Is this okay for all species, or only certain species?

Orchids are the "Cinderella" of the plant world; each has it's own set of needs. There is no "one size fits all" in any aspect of cultural parameters.

Sure, you can use the same potting mix for all plants, but you'll need to find the watering technique for each individual pot that works with it to give the plant what it needs.

Nobody can tell you what mix to use, as what works for them in their growing conditions may not work for you in yours.

As far as the Rhyncholaelia digbyana is concerned, it needs bright, full sunlight all day.

[Roberta]

Rl digbyana also needs a very open mix. I have found that it does better in baskets under my conditions. However you pot it, needs to pretty much dry between waterings if it is a mature plant. A seedling needs more moisture than the mature plant, but still needs lots of air. I wouldn't put any Catt in sphagnum in a pot. Or in spahagnum at all.

[Jmoney]

Originally Posted by Roberta

Rl digbyana also needs a very open mix. I have found that it does better in baskets under my conditions. However you pot it, needs to pretty much dry between waterings if it is a mature plant. A seedling needs more moisture than the mature plant, but still needs lots of air. I wouldn't put any Catt in sphagnum in a pot. Or in spahagnum at all.

Several years ago I discovered a number of cattleya growers were using sphagnum (Chadwick as mentioned, also Steven Christoffersen and OV Orchids in CA). I was not happy with my typical mix and began switching over. It is not in my opinion a "beginner" potting mix but I have had good results. The moss needs to be potted tight and with the excess water squeezed out. For my conditions I use clay pots only and am liberal with styrafoam peanuts in areas without extensive roots (i.e. backbulb areas). I have a digbyana in it but of course it has to be nearly dry before watering!

[estación seca]

Chadwick and Orchids Amore pot Cattleyas in moss. It works well when the grower understands how to water and the conditions are correct: warm to hot, so it dries rapidly.

Keep in mind Rhyncholaelia/Brassavola digbyana is considered by many to be a very slowly growing plant.

I think if you want more aeration with a particulate mix you should use larger chunks rather than mixing in other things. I have heard several commercial growers say they mix in perlite chunks because they hold water longer than bark, not to improve aeration. This lets them extend the watering interval and cuts labor costs.

How did you decide you needed to repot the Angraecum?

[Dimples]

Perlite doesn’t hold water, did you mean rockwool?

[Ray]

In my experience , perlite holds lots of water, and wicks it really well, too.

My first attempts at what is now S/H culture used very coarse perlite as a medium. It worked well, but the perlite it too friable, and soon (months) ended up with a root-suffocating sludge at the bottom of the pot.

Particle packing is a freshman level course in ceramic engineering. The get the maximum amount of free void space, you need spherical particles of uniform size, yielding some 40% or so open voids. Any irregularity in size or shape, or the addition of a phase with a different particle size, decreases it.

That's one of the reasons Orchiata is so good, because it's graded well.

If you mix enough stuff of different sizes, you can approach 0% open space.

Having said that, if the particles are less spherical and have more flat shapes and surfaces, a second particle phase can work to keep them separated.

[Dimples]

Originally Posted by Ray

In my experience , perlite holds lots of water, and wicks it really well, too.

Sorry, should have said it doesn’t hold any water internally vs bark that acts like a sponge after awhile. I can’t imagine adding perlite to a smaller bark would increase the total water holding capacity of the pot. Perlite can definitely hold water between particles and in surface depressions/pockets, but unlike bark it doesn’t have internal water storage. I’ve cracked open a number of larger pieces after long soaks and the inside has always been dry.

If you all have had different experiences, could it be regional differences in feed materials or processing methods?

[estación seca]

Look up the Orchids Amore posts here on growing B. digbyana in moss.