Expanded clay for Phal repotting?
 

I just had one of my phals die on me, pretty certain it was because I hadn't repotted it and the sphag moss led to root rot. SO. Time to seriously think about repotting my other babies before the same thing happens! I've been thinking about expanded clay, it's pretty, leads to good aeration and has good water retention but won't lead to root rot (that I know of). Any of you used that type of potting medium for your phals yet?

It has some good properties that make it very useful as orchid media but it does dry very quickly and requires frequent watering. In the book 'Moth Orchids' the author suggests using a mix that includes expanded clay with a good bark, like Orchiata.

Unless you have the time to water every day I wouldn't recommend it.

Ugh, it dries out that quickly? I guess it wouldn't make a good substitute for the gravel in my hydration trays then either...

I use LECA for Phals and do well with it. It isn't for everyone and you have to understand what the plants need whether you use LECA or conventional media.

So, FWIW, I have them in plastic pots on heat-mats under lights. The heat-mats will go into storage when the weather warms up.

They are all doing great but I started with reasonably healthy plants!

Have you considered S/H culture. LECA works really well for that!

Bill on the PlantzNThings channel on Youtube uses a mix of hydroton and sphag moss. It seems to work well for him and it is something I'd like to try once I've used up all my bark.

Actually, it would work quite well in your hydration trays, as it tends to "wick" better than straight gravel. However, if your concern is about having to "top up" too often, you're not really getting the point of hydration trays (which are generally not that effective at increasing ambient humidity - they just don't have enough surface area) - the more water you can get out of them into the air, the better. :)

I am moving more and more towards inorganic mixes, and quite like LECA, but you will need to water often - I don't mind that, but some people will. You may find other inorganic mixtures which dry less rapidly, or a hybrid organic/inorganic mix which you like. And as Ray suggest, semi-hydro (visit his website firstrays.com) may well work for you, depending on how well your plants go through the "adjustment" to its somewhat different growing conditions.

I think that you will find that combination will be a problem, long term.

As the moss starts to break down, is becomes a soppy, clogging mess that will suffocate the roots, but being down in the mix, rather than on top, as when using sphagnum "straight", you cannot see it happening.

Then there is the added question: Do you want to pick all of that old moss out of the LECA when you repot?


Ray Barkalow
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I grow Leca, without S/H technique. Phals do well in it for me and I'm transitioning most of them to it.

In my climate I don't need to water every day, but probably water every 3-4 days for most of the phals depending on how quickly they are drying. It would dry quicker in a dryer climate though.

I don't use S/H for Phals because in my climate it's too cold for them to grow that way (as the evaporation causes the clay to cool). They are fine in the summer in S/H but struggle in the winter.

Personally it's my first choice of medium for Phals.