Why such small pots?

[Rothrock42]

Regarding catasetinae culture I often see statements like "Plants should be kept in relatively small pots." and most of the photos I've seen have pots where the pseudobulbs pretty much take up the whole pot.

I'm wondering why?

I'm pretty new to growing them and have only bloomed one and taken it through the winter. It now has another growth and bloom spike. I've also put it in a larger pot. I've also got a couple of new ones (because they are so cool) and I've also put those in larger pots that they came in. In my [limited] experience the roots pretty much fill the pot and even come creeping out -- and that is the larger pot. I just can't imagine what they would do in the smaller ones.

Maybe it is something about overwatering as they come out of dormancy and inducing bulb rot? But shouldn't careful water monitoring during that period head that off Any other reasons that people know?

Am I just missing something or setting myself up for a big gotcha moment?

[isurus79]

I wouldn't worry too much about pot size for these guys. Just don't make it overly huge.

[bil]

Originally Posted by Rothrock42

Am I just missing something or setting myself up for a big gotcha moment?

Careful! The tiny pot mafia will have you wearing concrete overshoes on the sea bed if you go around criticising perceived wisdom like that.

The fact is that you are quite right. Observe all the shrieks about "Don't put orchids in big pots!" foor long enough and you will see that usually, the people concerned are conflating depth with size.

There simply is no difference between a pot that is three feet in diameter, and one that is three inches, providing the media is the same, and the depth of the media is the same. It is better to put an orchid in a pot that is a foot in diameter and three inches deep, than it is to put it into a pot that is 6 inches i diameter and 6 inches deep.
Air HAS to get to the roots easily, and it gets to the roots better in shallow pots. Bigger diameter, shallow pots are best because they allow the roots to spread out more, they allow more roots to grow and so the plant can grow better.

---------- Post added at 07:31 AM ---------- Previous post was at 07:29 AM ----------

PS, yeah, I know that not everyone has the space for big pots, but this question is about what is best for the orchid, not you.
I find that for most, 8" Diam and 3-4 inches deep is the optimum.

[Rothrock42]

The other benefit for me with catasetums is that they tend to be top heavy and a wider pot lowers the center of gravity.

There seem to me to be a lot of wins. I plan to keep doing this until I find a reason not.

bil - It is difficult to find wide shallow pots, especially because I like the clear ones. I know you mod your pots. Maybe next year I"ll have to do that with my growing catasetum collection. I'm up to four now.

[bil]

Originally Posted by Rothrock42

The other benefit for me with catasetums is that they tend to be top heavy and a wider pot lowers the center of gravity.

There seem to me to be a lot of wins. I plan to keep doing this until I find a reason not.

bil - It is difficult to find wide shallow pots, especially because I like the clear ones. I know you mod your pots. Maybe next year I"ll have to do that with my growing catasetum collection. I'm up to four now.

It never cease to amaze me that you can't buy wide, shallow pots even in the US, which is the country of commercial choice, if ever there was one.
I can grasp that clear pots are a help with catasetums, especially when the roots need to be a certain length before watering, but I am dabbling with yet another heresy, and I am wetting those short roots.
Don't tell anyone, but so far it is working well.

[PaphMadMan]

I can't really comment on Catasetinae since I have so far avoided that particular orchid obsession. Need to save some new mania to make my twilight years interesting.

But for orchids in general, there are many that don't bloom at their best (or much at all) until they have filled a pot, whether that is a 2" pot or a 12" pot. For a plant with a long and indefinite life cycle and relatively slow growth (many orchids) it makes sense to maximize use of available resources before shifting from primarily vegetative growth to reproductive growth. Coupled with the fact that is easier to avoid overwatering an orchid in a small pot, a major issue for many new growers especially, the general recommendation of small pots does make some sense.

Wider shallower pots do make sense for many orchids that aren't held back in flowering by room to roam. Bulb pans are the type most generally available, though not as wide and shallow as could be useful. Deep large pots are good for many more terrestrial orchids. In either case, the larger the volume of media the more attention must be paid to avoiding soggy media that breaks down long before the orchid would otherwise need to be repotted. Always a juggling act, and rarely just one way that works.

[bil]

Originally Posted by PaphMadMan

But for orchids in general, there are many that don't bloom at their best (or much at all) until they have filled a pot, whether that is a 2" pot or a 12" pot. For a plant with a long and indefinite life cycle and relatively slow growth (many orchids) it makes sense to maximize use of available resources before shifting from primarily vegetative growth to reproductive growth. Coupled with the fact that is easier to avoid overwatering an orchid in a small pot, a major issue for many new growers especially, the general recommendation of small pots does make some sense.

Wider shallower pots do make sense for many orchids that aren't held back in flowering by room to roam. Bulb pans are the type most generally available, though not as wide and shallow as could be useful. Deep large pots are good for many more terrestrial orchids. In either case, the larger the volume of media the more attention must be paid to avoiding soggy media that breaks down long before the orchid would otherwise need to be repotted. Always a juggling act, and rarely just one way that works.

Well, the question isn't the volume, it's the depth of the media.
Look, a foot diam pot that is three inches deep contains way more media than does a pot that is 6 inches deep and 6 inches in diam. It's the 6 incher tho that will be most at risk from root rot.

What is most interesting is that some orchids have to fill the pot before they bloom.
Can you tell me please what those orchids are? Only in all the time I have been asking questions about this, you are the first person to mention it and I would like to know more.

---------- Post added at 04:15 PM ---------- Previous post was at 04:13 PM ----------

"Deep large pots are good for many more terrestrial orchids."

Agree, - that is a different kettle of fish tho.

[PaphMadMan]

Originally Posted by bil

Well, the question isn't the volume, it's the depth of the media.
Look, a foot diam pot that is three inches deep contains way more media than does a pot that is 6 inches deep and 6 inches in diam. It's the 6 incher tho that will be most at risk from root rot.

What is most interesting is that some orchids have to fill the pot before they bloom.
Can you tell me please what those orchids are? Only in all the time I have been asking questions about this, you are the first person to mention it and I would like to know more.

Even in the wide 3" deep pot the area that has no roots will stay wetter longer simply because there are no roots there removing moisture, and that reserve moisture outside the root zone can wick moisture back to the center too. Probably not a major effect if it is warm and dry with good air movement, but it can be an issue in a cool greenhouse in winter.

It isn't necessarily that they "have to" fill the pot before flowering, but they may tend to maintain a more vegetative growth phase until they do. This may be a contributing factor in a lot of "why won't my orchid bloom?' questions. Reduction in nitrogen fertilizer is often part of the answer to those questions, and the unused space in the pot represents the same thing as the nitrogen, excess resources that tend to promote vegetative growth. This is probably less of an issue with many of the most popular orchids that tend to be the products of many generations of breeding and selection for quick and easy blooming.

Probably the best example of an orchid that tends to bloom easiest and most abundantly when it has completely filled the pot with roots is Psychopsis.

[bil]

Originally Posted by PaphMadMan

Even in the wide 3" deep pot the area that has no roots will stay wetter longer simply because there are no roots there removing moisture, and that reserve moisture outside the root zone can wick moisture back to the center too. Probably not a major effect if it is warm and dry with good air movement, but it can be an issue in a cool greenhouse in winter.

It isn't necessarily that they "have to" fill the pot before flowering, but they may tend to maintain a more vegetative growth phase until they do. This may be a contributing factor in a lot of "why won't my orchid bloom?' questions. Reduction in nitrogen fertilizer is often part of the answer to those questions, and the unused space in the pot represents the same thing as the nitrogen, excess resources that tend to promote vegetative growth. This is probably less of an issue with many of the most popular orchids that tend to be the products of many generations of breeding and selection for quick and easy blooming.

Probably the best example of an orchid that tends to bloom easiest and most abundantly when it has completely filled the pot with roots is Psychopsis.

OK, thanks.

I speak from having done a lot of experimenting. Keep the medium shallow enough, and yo have to water every damn day just to keep them alive.

2" deep of fine bark with Den phals is bone dry here by the second day. Now if you were in the depths of winter, cool and humid it would last longer, but then in those conditions you would modify your watering schedule.
Point is that with open, free draining material, it dries out so fast in shallow containers that the media isn't permanently wet, so it takes longer to break down too.
Plus, you get enormous root growth on plants with wide shallow pots, and surely that's a good thing?

As for unused space, what unused space? Roots spread out and grow at one hell of a rate.

[AvantGardner]

I have overpotted and underpotted before. Much better to underpot. I underpot and hang them. I water and fertilize (almost) every day.

This gives the plants more aeration to the root mass and more exposure to nutrients