Lots of thinking about the reality of repotting orchids lately.

[PuiPuiMolcar]

Im starting to become very paranoid about whether repotting is necessary or not, there's so much I dont understand the more I see how other vendors and owners are taking care of their orchids.

I bought several dendrobium in soils, full of rotting roots are while back and yet they still arent' doing well when I repot them in a "proper" medium.

There are many online resource tell me that I should repot phal, cattleya, den etc every two years because the media decompose. And yet I went to Andy's orchid and he told me some of his cattleya stay in the same pot forever, heck even my local swapmeet orchid vendor do that too.

Does it matter if I let my cattleya stay in the same pot forever even if some of its root are dead, At what point does the medium even matter?
I thought I've got it after all this time but I only ended up digging a bigger rabbit hole.

[Ray]

Here's my "take" on that:

As orchid roots grow, the cellular structure is optimized for the conditions to which they are exposed, and once grown, they cannot change.

When that environment is changed - whether that is due to decomposition of the medium or a change to a different medium (and we should not forget that fresh medium and the same medium several years later are "different") - those roots are no longer optimal, so will start to fail. The bigger the difference, the faster they will do so. This, by the way, is why repotting just as new roots are emerging is important; they will support the plant as the old ones fade away.

The goal is to have the environment be as consistent over time as possible.

Stephen Male, owner of Fishing Creek Orchids and one of the best growers I've ever met, repots all of his plants annually, thereby avoiding significant changes in his potting media and the related issues.

[Roberta]

Some media need replacing faster than others...the goal is always air around the roots. Cheap bark tends to torn into mud fairly quickly. Hard, high quality bark like Orchiata or Kiwi bark, can stay good for quite a few years. Sphagnum moss, it depends a lot on how it is used, but in general doesn't stay good more than a couple of years. Inorganic media like LECA or volcanic rock won't break down at all, but may eventually build up salts and other crud and need to be replaced. Water quality, watering frequency, humidity... all are factors. Also, some plants force the issue... growing along a rhizome, they eventually climb out of the pot.

[estación seca]

The most important factor in repotting is doing it at the correct time. Do it when new roots are just forming. If you do it at other times it may be many months before new roots form, and the plant will struggle to absorb enough water on the roots recently damaged while repotting.

[Mountaineer370]

FWIW, I use Orchiata almost exclusively nowadays, and I have yet to see it decompose. The orchids I have don't get repotted unless they have actually outgrown their present pot and need a bigger one. This could be two, three, or even four years. It's working for me; your mileage may vary.

[estación seca]

I did some more thinking about your original post. Most of your uncertainty is just inexperience. You haven't seen yet how the different orchids grow through the years. Believe in yourself; you will learn it the way we did. We stumbled through the exact same things.

As for Dens, there are many different kinds from different climates with different seasonal temperatures, rainfall and humidity. You need to know which kind you have in order to give what the plant needs. Which Dens do you have? One thing they all have in common is what I wrote before: It is best to repot only when new roots are forming. In my experience Dens are more sensitive to repotting at the wrong time than are many other orchids, because their roots tend to be so fine and easily damaged.

Bark media break down faster when continually moist. Orchids that need to stay moist, like Bulbos, Paphs or Phrags, generally need to be repotted every year or two at the most. All the prize winning slipper growers I have heard speak repot all their plants every year if they can.

Dens in the Latouria, Antennatum (Spathulata) and Phalaenopsis groups also should stay moist, so they usually need more frequent repotting. For this kind of Den. it is a good idea to use the smallest pot into which the root ball fits. They may have a lot of roots and a tight root ball, but they don't always spread very far from the plant. Most Dens have much shorter rhizomes between upright growths than do most other sympodial orchids. When well grown they don't crawl out of the pot as fast as do most Catts or Bulbos, which is another reason they are potted tightly.

Phals don't tend to outgrow pots because they make very little horizontal growth. Sometimes they form clusters of rosettes from the base, but most of the time Phals are repotted when the medium is getting old, or the stem is elongating so much the newest roots are far out of the medium. Depending on growing conditions this may be 2-4 years for most people. Using very large bark one can water Phals very often, even daily, and they like this. But people who can't look at their plants every day generally use smaller particle medium and water less frequently, when the plant is dry or nearly dry. This means Phal medium tends to last a little longer than Bulbo., Paph. and Phrag. medium. I grow my Phals in LECA clay balls because it doesn't break down. This means I don't have to repot right away when the medium breaks down; I can let the plant go for a little while before getting to it.

Most people let mature Cattleyas get dry or nearly dry between waterings. (Most small Catt seedlngs don't like being dry.) A few species, and their primary hybrids, must be kept nearly completely dry all winter. Because of this medium for Catts tends to last longer. The newest Catt roots are at the youngest part of the plant, and the older roots don't contribute much. So it's OK if a large Cattleya has very old roots in questionable medium near the center of the pot. I have bought and unpotted huge Cattleyas in 3-gallon/12 liter nursery pots in large bark. The plants looked amazingly healthy and had many leads. There were usually minimal roots at the center of the pot, and almost all the roots were growing around the outside of the bark mass along the walls of the pot. This is why many people prefer growing Catts in much lower, wider containers than used for orchids than need to stay moist; they don't root much into the centers of deep pots.

Catts grow horizontally, and they will walk out of a properly sized pot in 2-3 years after repotting. This is a matter of experience, too. Catts can crawl out of the pot and continue growing just fine if the ambient humidity is good.

Many of the bifoliate Catts do best in baskets with just a few chunks of extra large medium, or no medium at all. But this doesn't work in most homes where relative humidity is usually too low for this; when growing the bifoliates indoors, people tend to use large bark and water frequently when in growth, letting them get almost dry between waterings, and keeping them very dry most of the winter, with only occasional light waterings.

[SADE2020]

@Estacion.. thanks for such a wonderful explanation.

Please tell me what is your medium preference for Catts in your area (Arizona..)?

Thks

[estación seca]

Originally Posted by SADE2020

Please tell me what is your medium preference for Catts in your area (Arizona..)?

Growers here use bark and LECA. I haven't seen many growing in sphagnum moss. Almost nobody grows anything on mounts unless they have a greenhouse.

[SADE2020]

In regard to your doubt... Let say that will also depend on YOU.

You don't like to repot?
Do you feel better not dealing with roots ?
Avoid Repot period!!!!

How? As the above explanation, look for a medium and culture optimal for your condition and that don't need much reporting, then push the plant development with other sources; optimal condition (Temp-humidity-aircirculation-fert+Amino).
If you get new plants; wait 2 yrs ..or so for report, until it get really used to your environment and you know the pant well.

This is a hobby....play it as you like! Do what sound better for your "enjoyment".

Good luck!

[PuiPuiMolcar]

Originally Posted by estación seca

I did some more thinking about your original post. Most of your uncertainty is just inexperience. You haven't seen yet how the different orchids grow through the years. Believe in yourself; you will learn it the way we did. We stumbled through the exact same things.

I can't thank everyone here and especially estacion eough for taking your time pouring your years of experience on a newbie like me. I'm quite new to this hobby yes, it all started from taking care of my parent's sick orchids then turned in to a stubborn obsession. I get frustrated, but I still love learning, I am thanksful that I've found this forum, it's way better than using Reddit or facebook's groups.