I think it depends on what the roots look like. If it doesn’t have many roots, you have to keep it in the smaller pots. Putting a small plant in a ”too big” pot is a recipe for disaster. Not sure what ”normal” potting mix is, but if you've had success with it for other plants, it should be fine.

If you want to put your succulents in a faster draining mix, what is most often recommended here is commercial cactus & succulent mix combined 50/50 with pumice or perlite, available at your nursery. But if your plants are doing ok in your mix, then you must be watering carefully so they don't get too wet. As you probably know succulents store water in their leaves and so don't appreciate being overwatered. However, if you plan to add any more succulents to your collection, you might consider getting the mix described above.

Your mix looks fine for your pretty fern.

My 2 cents.

Fern:

Nice plant. You can go up in pot size, judging from its size.

Choosing an Appropriate Size Container

How large a container ‘can’ or ‘should’ be, depends on the relationship between the mass of the plant material you are working with and your choice of grow media. We often concern ourselves with "over-potting" (using a container that is too large), but "over-potting" is a term that arises from a lack of a basic understanding about the relationship we will look at, which logically determines appropriate container size.

It's often repeated that you should only move up one container size when "potting-up". The reasoning is, that when potting up to a container more than one size larger, the medium will remain wet too long and potentially cause root rot issues, or at a minimum, limited root function. In reality, it is the size/mass of the plant material you are working with, and the physical properties of the medium you choose that determines both the upper & lower limits of appropriate container size - not a formulaic upward progression of container sizes. In many cases, after root pruning a plant, it may even be appropriate to step down a container size or two, but as you will see, that also depends on the physical properties of the medium you choose. It's not uncommon for me, after a repot/root-pruning to pot in containers as small as 1/5 the size as that which the plant had been growing in prior to the work.

Plants grown in ‘slow’ (slow-draining/water-retentive) media need to be grown in containers with smaller volumes so the plant can use water quickly, allowing air to return to the medium before root issues more serious than impaired root function/metabolism become a limiting factor. We know that the anaerobic (airless) conditions that accompany soggy media quickly kill fine roots and impair root function/metabolism. We also know smaller medium volumes and the root constriction that accompany them cause plants to both extend branches and gain o/a mass much more slowly - a bane if rapid growth is the goal - a boon if growth restriction and a compact plant are what you have your sights set on.

Conversely, rampant growth can be had by growing in very large containers and in very fast (draining) media where frequent watering and fertilizing is required - so it's not that plants rebel at being potted into very large containers per se, but rather, they rebel at being potted into very large containers in a medium too slow and water-retentive. This is a key point.

We know there is an inverse relationship between media particle size and the height of the perched water table (PWT) in containers. A PWT is water that fills spaces between soil particles and defies gravity by refusing to leave the pot. As particle size increases, the height of the PWT decreases, until at about a particle size of just under 1/8 inch, media will no longer hold perched water. If there is no perched water, the medium is ALWAYS well aerated, even when it is at container capacity (fully saturated).

So, if you aim for a medium (like the gritty mix) composed primarily of particles larger than 1/16", there is no upper limit to container size, other than what you can practically manage. The lower size limit will be determined by the medium volume's ability to allow room for roots to ’run’ and to furnish water enough to sustain the plant between irrigations. Bearing heavily on this ability is the ratio of fine roots to coarse roots. It takes a minimum amount of fine rootage to support the canopy under high water demand. If the container is full of large roots, there may not be room for a sufficient volume of the fine roots that do all the water/nutrient delivery work, and the coarse roots, too. You can grow a very large plant in a very small container if the roots have been well managed and the lion's share of the rootage is fine. You can also grow very small plants, even seedlings, in seemingly inordinately large containers if the medium is fast (free-draining and well-aerated) enough that it holds no, or very little perched water.

I have just offered clear illustration why the oft repeated advice to ‘resist potting up more than one pot size at a time’, only applies when using heavy, water-retentive media. Well-aerated media are not bound by the same restrictions. As the ht and volume of the perched water table are reduced, the potential for negative effects associated with over-potting are diminished in a direct relationship with the reduction - up to the point at which the soil holds no (or an insignificant amount) of perched water and over-potting pretty much becomes a non-issue.

Al

I guess the basis of my question is what size pot a fern likes ... my african violets would never want anything larger than their 4" pots. If this fern needs a 4" pot pot, too too, I'd go buy it one ... if it will be happy with the 5" pot, I'll use it ... It's getting repotted because it's new and currently living on the kitchen counter (not its final home ...) in the nursery pot it came in with a bag for a "saucer."

I guess the basis of my question is what size pot a fern likes ... When ferns are potted up, they need to go into a larger pot than they were in. The appropriate upper limit of that pot's size is determined by our choice of grow medium. Ferns have a rhizomatous root system, which means it's best to remove most of the soil and repot them into a pot of appropriate size. That size too is determined by our choice of grow medium. The more water-retentive the medium is, the more careful we should be about how large the pot is. There is no one size fits all rule; and, even the advice to move the plant up to only a slightly larger pot is based on the assumption you'll be choosing a water-retentive medium. The mediums I grow in would allow me to pot your plant in a 10 gallon tub and not have to give a moment of worry to whether it was over-potted. OTOH, Miracle-Gro moisture control or other MG products are probably not a good idea. My African violets would never want anything larger than their 4" pots. It's hard to emphasize enough how limiting it can be to a plant's growth rate, vitality level, and appearance, when it's rootbound. Tight roots can actually rob plants of more than 100% of their growth potential. I say that because tight roots can cause such serious shedding of roots, shoots, branches, and leaves that the plant is going backward in terms of biomass, which is the true measure of growth. No plant does better when it's rootbound, even if the results of being rootbound (more blooms, more compact plant, smaller leaves, shorter internodes) are pleasing to the grower. If your plant continues to grow, at some point it will definitely want a pot larger than 4". It's getting repotted because it's new and currently living on the kitchen counter (not its final home ...) in the nursery pot it came in with a bag for a "saucer." Your call, insofar as when you repot it, but true ferns are normally best repotted in early spring, a departure from when most houseplants should be repotted - June, in the N Hemisphere. Best luck, BB.

More About Being Rootbound

Al

Sorry, I should have been more specific ... my African violets would never want anything larger if I want them to flower. African violets prefer to be mildly root-bound when it comes to flowering ... (Source: https://extension.psu.edu/why-isnt-my-african-violet-flowering) ... generally African violets are recommended to be in pots that are a third the diameter of the leaf spread ... (Source: https://www.optimara.com/africanvioletcare3.html) ... my violets are in 4" pots and have 7"-8" spreads and aren't really pot bound, but there's generally at least one flowering most of the time (currently it's the double pink girl finishing blooming).

I guess I'll just go with the 5" pot, since it doesn't require buying a new pot.

Anyways ... moving on from pots, is there anything else I should know about growing ferns as houseplants? This is my first that will live inside ... The things outside are pretty much unkillable, but I'm assuming this is a bit more delicate.

I get where you're coming from, completely; but for clarity, no plant prefers being grown tight, the grower might prefer to grow the plant tight for the few extra blooms the plant produces as a result of the stress caused by tight roots; but, tight roots are still stressful to plants, always a negative factor, which limits a plant's ability to realize all of its genetic potential. All else equal, plants with room for roots to run will grow faster, be healthier, and be better equipped to fend off disease pathogens and insect herbivory. If Mother Nature thought it was advantageous for plants to be grown tight, she would have arranged for their root systems to grow in a tightly tangled mass, occupying only a small volume of soil immediately beneath the plant's stem, but we know that occurs in nature only when the root's ability to run is physically limited by rock, concrete, other. Again, I understand where your POV comes from, but my reply is meant to provide clarity for others.

Ferns love soils that drain quickly/ thoroughly and are rich in organic material. If I was going to build a medium for ferns it would be

6 parts of pine bark screened 1/8-3/8"

1 part perlite

1 part par-boiled rice hulls

1 part peat (skip the peat if you don't screen the bark)

dolomitic (garden) lime @ 1 tbsp/gallon or 1/2 cup/cu ft

I hope that helps. The most important part is that it's very well-aerated and retains moisture well w/o holding water in the larger spaces between soil particles.

If you decide to use a medium that leaves you with concern it might hold too much water, try this ..... in fact, try it for any planting of a manageable size:

Newton's First Law

For conventional container culture, it's a given that saturated/partially saturated media rob roots of the oxygen they need to function normally and efficiently. At best, soil saturation robs your plants of immense measure of potential in areas like growth, appearance, yields, ….. At worst, plants unable to cope with the strain of drought stress caused by saturated media will succumb to it. This isn't a 'scare tactic, it's a very simple and straightforward observation that will be difficult to disagree with a straight face.

Newton's First Law of Motion states that an object will remain either at rest, or in motion at a uniform rate and in a straight line unless acted upon by an external offsetting force. In this case, we will designate the 'object' as excess water in your potting medium. At risk of my being redundant, the 'law' can be seen as a simple statement about inertia, that objects will remain in motion and in a straight line unless a force acts to change the motion. To put the law to work for you/your plantings, you should water to beyond the point of total soil saturation - so the medium has been completely saturated and at least 15-20% of the water you have applied has exited the pot. Unless your soil is purposefully constructed to eliminate all/nearly all excess water, it's extremely probable, when the pot has stopped draining, there will be too much water in the potting medium for the plants' liking.

To eliminate this excess water: immediately after a thorough watering, hold the pot in one hand over the sink, lawn, or over-sleeping significant other and move it downward, then sharply reverse the direction to upward. You'll immediately note that a good measure of 'excess' water will “continue downward in a straight line” and exit the drain hole. The sharper the reversal of direction, the more water exits the drain hole. When you have repeated the exercise until water no longer exits the drain hole on the reversal of direction, you will have eliminated all excess water and your plants will regard you with a newfound sense of awe.

Al

Huh, I'd never thought about shaking the plant to expel water ... I tend to give a light shake while still over the sink to keep from dripping during transfer back to outer pot or saucer. For attached saucers, I just tilt in all directions, let sit on sink or counter for a couple minutes, and then tilt again before returning. (Some of the saucers don't hold much, and they sit on wood surfaces, so floods would be bad ...) Any similar suggestions for attached saucers? (To be clear, I'm not talking about self watering ... there's still a drain hole and no reservoir, the saucer is just attached.)

Any similar suggestions for attached saucers? Yes. Your pot shouldn't sit in effluent that exits the drain after you water. We flush plants to limit the build-up of salts (in the medium) from fertilizer solutions and tapwater. Allowing plants to sit in the effluent provides a pathway by which any salts which have been flushed out can make their way back into the pot. The pathway quickly allows the solution in the collection saucer to reach a state of isotonicity (balance), so the level of salts in the saucer and the soil solution will be equal. Pots should be raised above the highest level the effluent will ever reach to eliminate the pathway back into the medium.

One way:

This is not a problem for plants easy to handle so they can be watered at the sink, allowed to drain, then returned to their collection saucers. Since I'm mainly talking about large plantings, something beyond the impromptu pots feet (plastic bottle caps, medicine bottle caps, ....) must be used. I have found that small blocks of composite lumber run through a table saw and cut to 3/4 x 1 x 1.5" gives the grower 3 options insofar as how high they want the pot to sit. Another good choice would be treated lumber of the same dimensions. 1" PVC pipe fittings (unions), stood on end, also work very well and cost about $.50/ea.

If you happen to be using a wick to help drain excess water, the wick should not be allowed to dangle in the effluent, as that too provides a pathway by which salts can make way back into the pot.

Al

Just thought I'd share my repotted fern ... I did use the 5" purple pot, and it turns out the poor little fern was severely pot bound, so sizing up was definitely warranted anyways.

Yes, I loosened up the roots when repotting.

This isn't its final home, but we put it back in the spot it had been before repotting to reduce stress (one big change at a time). The paper towel is just to protect the counter from the pot. It'll probably get a coaster or little feet when it goes to its destination (slate topped piece of furniture).

It's currently a couple yards away from an east window (not the window visible behind it ... that's a west window). It'll be going to a spot around a foot or so from a north window with sheers; I'm assuming I can just move it directly, unless someone wants to tell me otherwise ...