As I have mentioned, I have started changing my plants from bark to scoria and stalite, and the plants seem to be happy so far, although it is too soon to tell for sure. Yours has done well in scoria? The one I just ordered is a young plant in a small pot. I have some small scoria. Do you think that would be appropriate for a small plant? As it gets larger I can pot it in medium scoria (I actually prefer to put medium scoria in the bottom half of the pot because it is somewhat larger, and then I fill the top portion of the pot with stalite, because the medium stalite is somewhat less coarse than the scoria and I feel like the roots will be able to penetrate the stalite better than the medium scoria), and it seems to be working so well. Is Phychopsis temperemental about when it is repotted? Can I pot it in the small scoria as soon as I get it, or do I need to wait until I see new growth with new roots forming? That is assuming I don't have a repeat of my last Psychopsis fiasco and I have a new growth that actually gets big enough to grow roots haha. That was such a strange thing that happened with the first one I tried. I have a hard time imagining that the same thing would happen twice. But full disclosure, the plants were small and inexpensive, so I bought two just in case I had a problem with one of them lol. If they both do well and mature, then I'll have an extra one to trade for something I don't have.

---------- Post added at 07:44 PM ---------- Previous post was at 07:31 PM ----------

And by the way, how do Oncidiums tend to do in small scoria? I know it depends on your personal growing conditions and such, but I get a lot of rain in the summer, and I tend to be an overwaterer in the winter, so it seems like small scoria might be a good solution for keeping the roots on my Oncidiums in better condition.

J.S. ----- I think your plants will do just fine in scoria/stalite combination.

For baby plants with enough roots on them, I believe that small sized scoria will be absolutely no problem for baby plants. I have small sized baby Sedirea japonica growing in small size scoria. So will see how they go within the next month or two. If they stay nice and healthy, then they'll be fine. I just water mostly around the edges of the pot, and less toward the middle.

I have an incoming Sarcochilus ceciliae, which I'm just going to pop that into small sized scoria too, and see how that goes. Apparently online sources mention this sort of orchid does better or well with less water. Will see what happens anyway heheh.

Regarding repotting ------ I believe that many recommendations about waiting for active growth is definitely workable, and makes good sense. I think that is something that can be followed.

For myself, I will report however that - for my tropical conditions - orchids can arrive by mail at pretty much any time of the year, and I generally will just repot them right away - removing all the old media (eg. bark/perlite/moss etc) - checking for snails etc, and then putting into either the same pot or a new pot ---- with scoria. I generally spray with mancozeb too ..... pretty much all of the orchids that come in. Whether that is necessary or not ---- not sure. I just do that.

JS ----- my oncidiums in the tropical conditions are doing great in both small size and large size scoria. Humidity is quite ok here. No problems with the relatively thin roots in the relatively large 10 to 15 mm average diameter scoria. But I also have them growing in say 5 to 8 mm average diameter scoria too --- also no issue here. Doing really well. For the oncidiums here ----- the water drainage through the pot is really good. My oncidiums are Sharry Baby 'ruby' and Twinkle 'fragrance fantasy'.

Interesting. I have never heard of scoria/stalite. I look forward to reading more on it. What is a good quality brand?

nzadro - scoria is lava rock, I'm guessing there are specialized brands that are nice and aesthetic out there but I just picked up a bag of the landscaping stuff I found at the local home improvement store and am using that. Had to sort through since there are all sizes in the bag. This is one of the mediums I will potentially be using it for the psychopsis juvenile I just got.

Stalite is heat expanded shale from what I've been able to find about it. I know nothing of it but seems to be a very close lava rock replacement.

J.S. I took these pics 20 mins or so ago ------ showing the Oncidiums in scoria, and the Psychopsis in scoria (with the new leaf seen this time just peering out from under the juvenile paph leaf).

All the roots were thoroughly disturbed when I first got them ----- not only with bits of old media removed, but the roots run through with water from a garden hose.

Those look great. I think as my Oncidiums need repotting, I will switch to scoria/stalite. I just find the watering so much easier to get right with plants not in bark. I'm bad about waiting too long to repot, and the bark breaks down, and I don't adjust my watering to allow for slower drying time, and I end up damaging the roots keeping them too wet, and I'm also an overwaterer. I just love watering my plants. Potting in scoria seems to solve that problem, and my plants are doing great. They're just more vigorous and growing faster with larger growths than when I was growing in bark, and I recently repotted a Catt that had been growing in scoria, and the root system was amazing, and all I had to do was drop it into a larger part. Didn't have to disturb the roots at all. I was worried about being able to keep Oncidiums moist enough in scoria, but it seems to work fine for you, so I'll give it a shot. Thanks for the tips.

Plants that I've had a long time that need repotting, I always wait until I see new root growth, but like you, I usually immediately repot new plants to get them into my preferred growing medium. Even if it isn't the best time to repot them, I give them a treatment of KelpMax (thanks Ray! I just ordered the 10 liter jug, and I just got an email from you saying you shipped it) and that seems to greatly reduce any repotting stress. That KelpMax really is some miraculous stuff. But that's beside the point. Scoria and stalite are the way to go for my particular growing conditions and cultural habits, and I'll start planting my Oncidiums in scoria too. Those are the only ones I wasn't sure about so hadn't tried yet.

J.S. thanks for letting us know that you're trying the scoria/stalite combination. Keep us posted in the future about the good results from that combination.

For my oncidiums, I noticed that they can handle a lot of water just getting sprayed onto them (even around the bulbs) very well. Their roots appear to be fearless of lots of water. The drainage does help a lot here I guess.

But for some catts ----- and maybe other orchids, I think it can be handy to watch out for the amount of water that gets bundled directly under the orchid in scoria, where maybe the bulk of the root mass might lie (except when the pot becomes 'root bound' heheh).

I noticed in the past that even under my good tropical conditions, water hanging in and on the roots and around the media too long (or too much) can impact the roots negatively. That's what I noticed anyway. I think it's the same story --- where a big pot of scoria can possibly develop very watery conditions toward the centre or middle of the pot. That can possibly hurt some orchids.

On the other hand, if we purposely add water toward the sides of the pot (in a suitable band or width of our own choice), it eases up on the amount of water that gets bundled up into the middle of the pot.

And for the roots that eventually extend out to the extremities of the pot ----- the situation could 'probably' be getting towards 'water culture' ..... where the roots eventually get to regions where they will just transition into .... get more used to (or even fully used to). That's the 'roots meeting the very watery region under own terms' thing. This doesn't necessarily mean this method of watering should or must be done for every catt or orchid. But is an option for sure. The method is there if we ever need it!

It is true that the type of pot used (depth, etc) is a consideration. Shallow pots can help a lot ----- so water pooling inside the pot is probably much less of a problem with shallow enough pots. I've generally been using big and deep pots though ----- without issues when taking into account ways of watering.

My psychopsis fully opened on both spikes at the same time today! I think my 2 little Hausermann psychopses are about 4 years away from this size....maybe 3 years from a first bloom. Here are some pics with the sun lighting one of the flowers. Bliss.

That's a real beauty. Top photograph too. Excellent shot.

Here is my Saturday morning mini project. I moved this little one into inorganic medium of leca with some lava at the bottom so the leca doesn't fall out.

The medium on top was still pretty good, but the stuff in the bottom of the pot was pretty stinky and broken down. It seems they don't do much with the plants other than move up a pot size and put more medium on top.

Roots were pretty good, I trimmed a few of the old dead roots off the smallest pseudobulb but most of them were in good shape. The new growth was putting out a nice new root so hopefully it will acclimate to it's new home fairly easily!