Pot size for adult Phalaenopsis - Orchid Board

The Peloric Orchid · #1 10-06-2021, 10:38 PM

I've been raising some Phalaenopsis seedlings from flask. I'm pretty sure they need to be potted up into a larger pot, but I'm not sure what size to get. So I have two questions:

First, given that the pot in the attached photo is 4" square, should I repot into same size pot, or pot up into 4.5" or 5" (or larger) inch square pots? Many of these plants also have very long aerial roots.

Flickr

Second, while I'm ordering new pots, I may as well save on shipping. What's the largest size pot I should have on hand for my adult phals?

estación seca · #2 10-07-2021, 12:08 AM

It depends. If there are plenty of roots down in the medium you can leave the aerial roots exposed. If not you need something into which you can fit at least some aerial roots.

You can often soak bare-root plants for an hour or more to get the roots more flexible for twisting into the pot. Some may break. It is generally the velamen that breaks, and the water-conducting core remains intact. I don't worry too much about breaking some velamen.

The largest pot depends on how much space you have. The very low but wide bulb pans, or wide clay dish pots, can accomodate a wide root system.

Many people settle on a maximum pot size and figure out how to stuff the roots into that pot. It is one way of dealing with limited space.

camille1585 · #3 10-07-2021, 01:39 AM

What size to repot into really depends on the root mass. I have a bunch of young Phals at home, and last time I bought some supplies I got a whole range of pot sizes (from 2 to 4 in). When I repot I use the smallest pot the roots will comfortably fit in, and use a twisting motion to get very long roots to coil up a bit.

As to adult Phal pot size, that depends on the species/hybrid. The smaller ones do well in 10cm pots (Phal equestris, Phal pallens...), while my larger ones are generally in 12cm pots. I have a couple in 15cm pots as well, but those are rather old, large Phals (That would be 4,7 and 5,9 in).

Paphluvr · #4 10-07-2021, 07:37 AM

I'm curious about your potting medium. It seems to have no texture. Can you tell us what you're growing in, please?

Ray · #5 10-07-2021, 09:17 AM

I think one must consider potting to be a "system" of several variables that can be adjusted independently to make it "work" to meet the specific plant requirements in your growing environment:

pot dimensions
pot material
pot design
potting medium

Starting with the size of the root mass, you need a container that will accommodate that, as Camille stated, but that's just a starting point.

The potting medium stays wetter longer in a bigger pot.

The potting medium stays wetter longer in a plastic pot than in clay.

The potting medium stays wetter long in a container with solid walls that it would in a perforated or slotted pot.

So right there you have three variables than can be manipulated in conjunction with the choice of potting medium, and they vary all over the map, too.

Roberta · #6 10-07-2021, 01:23 PM

A trick that you can use if you need to use a larger pot but don't want to leave a wet "dead zone' in the middle due to too much volume for the surface area... invert a small pot or plastic basket under the roots in the center of the pot. Then when you fill in with medium, you will have a nice air pocket in the middle instead of a soggy lump of medium.

The Peloric Orchid · #7 10-07-2021, 07:51 PM

Ray and Roberta, would using an inorganic medium, like rockwool and LECA, cause less of dead zone than using sphagnum moss?

Roberta · #8 10-07-2021, 08:08 PM

In a larger pot, sphagnum is likely to be difficult to get the watering right... it'll tend to stay too wet, but if it dries out too much, is hard to re-wet. If it were my plant, I would gravitate toward medium-sized bark, loosely packed (just enough to hold the plant) which will allow for good drainage. But that's me, with my watering practices. Others, who use LECA or other inorganic media would be better able to advise on that than me (since I don't use it) The goal, whatever you do use, is to have an environment that has lots of air space, since Phals want "humid air' more than "wet". There are lots of ways to achieve that, but that's the goal.

Fairorchids · #9 10-07-2021, 09:59 PM

I am puzzled that nobody has commented on potential plant size. Since these plants spike from plants less than 12" across, I don't think that they will grow as large as most of the NOID Phals in the stores.

From that observation, I would say that 4" pots should generally suffice, though you might want to have a few 5" and/or 6" pots on hand - just in case.

camille1585 · #10 10-08-2021, 01:29 AM

Quote:

Originally Posted by Fairorchids

I am puzzled that nobody has commented on potential plant size. Since these plants spike from plants less than 12" across, I don't think that they will grow as large as most of the NOID Phals in the stores.

I did mention it in my post.

Also, not sure what you mean by " these plants" as the OP does not mention what the Phal in question is, it might be something that gets rather large once mature.