How do you know when it's time to repot a plant
The plant I have in mind is a large leafed jade plant
. If has been in the same pot for at least 10 years. It turned out to be a large leaf Jade 0lant. It was a out 3" tall when first planted. It grew very very slowly until the past year. Then it just seemed to spring to life. It now has 3 large branches about 10" to 12" long now. Advise would be welcome.

Hi, Colleen. Root congestion is an insidious robber of your plant's potential in terms of growth and vitality. Symptoms include limited growth or no growth at all, and on branching plants, most growth is concentrated near the tips of branches (branch apices) where extension growth takes place. This occurs by way of shedding of oldest leaves and leaves closest to the trunk. The stress caused by root congestion can first be measured in the roots before the visual cues mentioned become conspicuous. When the roots of your plant become congested to the degree the soil/root mass can be lifted from the pot intact, the plant would benefit from repotting or dividing, depending on how its roots are structured.

What changes (in your care regimen) did you make that might have caused the plant to turn around? Typically, plants 10 years old that call the same pot 'home' for that time span don't just suddenly decide to start growing like crazy.

Also, there is a significant difference between repotting and up-potting or potting up. The former eliminates all stress associated with root congestion until it eventually becomes an issue again. It includes bare-rooting, root pruning, and a change of grow medium. Potting up is easier, but doesn't eliminate the stress of congested roots; rather, it ensures that root congestion in the middle of the root mass remains as a limiting factor until a pair of hands gets into the center of the root mass to correct the congestion and remove heavy nonessential roots.
Al

Are you able to add a pic? Firm believer in and practitioner of the excellent info above, because of the excellent advice above from long ago, so my next comments are not discounting or detracting. In particular about Jades, have seen so many decades-old Jades over the years that have never been disturbed.

I've never found much roots when uprooting Jades or repotting them. Even when put in the ground for 7-8 months and the one amazing specimen that I stuck in the ground as an unrooted branch and it survived 2 winters before I got nervous about it and pulled it up. Even that just had a little "poof" of roots, like wiry hair. They did look congested but I think that's just the way Jade roots are. It does seem like it would take decades for roots like that to fill a gallon size pot.

When they get top-heavy and are in danger of falling over, moving to a bigger/heavier pot can help. If you do disturb it, don't water for a few days to allow any wounds to the roots time to dry and seal.

You are right, very small gnarly root system. They do best in a wide, shallow, heavy pot - a wide heavy base to keep them upright.

It's more difficult to grow plants (especially those that don't tolerate wet feet with grace) in shallow pots than in deep pots; this, because at container capacity (when the soil has stopped draining and is holding as much water as it can) deep pots will have a higher % of unsaturated grow medium than shallow pots.
The images below are filled to the top with a grow medium that supports excess (perched) water.

If the pots are 12", 8", and 12" deep. It's easy to see that the shallow pot has less than 25% of well aerated medium at container capacity, while the 8 & 12" pots have about 62% and 75% (respectively) of well aerated media at container capacity.

What the plant would prefer is, being grown in a deep pot with plenty of room for roots to run ..... not a shallow pot that quickly constricts roots and leaves only a small % of unsaturated medium after a thorough watering. It's better to eliminate both horns of a dilemma than to choose the lesser of two evils.
Al

I hear what your all saying about the size of the pot to have it in. I will post a picture of the plant and pot its in and has been in for past 10 years. Hopefully you'll be able to tell me what size pot it should be in. Also, what kind of soil. When I was given this tiny plant i was pretty ignorant about growing house plants. I just planted it in regular potting soil. I did not know or understand that different plants have different soil or pot requirements. This has been a long and interesting journey. I am and probably will always be on a learning trip. Hence the saying, you learn something new every day.

What size pot is appropriate is somewhat determined by the current size of the soil/root mass, but primarily by your choice of grow media.

I grow succulents in a very fast-draining, highly aerated grow medium,

so I'm used to seeing roots of Crassula, Portulacaria, and virtually any succulents I grow filling the pot completely with healthy roots within a 1-5 year period depending on the plants' normal rate of growth. Any time a jade is in a pot for several years yet shows a small gnarly root system, there is something in the care regimen that is having a serious negative impact on root function, at a minimum, with significant potential for infection by fungal root pathogens.

This might prove helpful:

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/ over-watering 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

Agoo said: I hear what your all saying about the size of the pot to have it in. I will post a picture of the plant and pot its in and has been in for past 10 years. Hopefully you'll be able to tell me what size pot it should be in. Also, what kind of soil. When I was given this tiny plant i was pretty ignorant about growing house plants. I just planted it in regular potting soil. I did not know or understand that different plants have different soil or pot requirements. This has been a long and interesting journey. I am and probably will always be on a learning trip. Hence the saying, you learn something new every day.

The pot should be an inch or two bigger than the root ball but jades have relatively small root systems and are naturally top heavy. Make your new mix nice and gritty and choose a heavy, wide and low pot with lots of drain holes (I cover the holes with craft screen). If you wait to water until you notice the leaves are slightly soft when you squeeze one between your fingers, you won't overwater.

If you are keeping your jade inside, put it in your sunniest window and rotate it 1/4 turn every week. If the edges turn red, the light is right and come December, it might even bloom.

@Agoo No one can provide meaningful advice insofar as what size a pot should be unless they rely on assumptions, primary among them is the assumption that you don't know better than to use a medium which disallows you to pot up to a significantly larger pot because it's excessively water-retentive. If the assumption is invalid, the premise is invalid. As I noted there can be situations in which, if the grow medium is appropriate, that you could move your plant to a 10 or twenty gallon pot filled with that grow medium. In order to suggest you should only pot up an inch or two in pot diameter and depth, the assertion is being that person has a handle on the current size of the root mass, the grow medium you will be using, and your watering habits; this, because all 3 are used to determine the most appropriate pot size, and that information hasn't been available. In fact, in most cases when growers repot instead of potting up, especially if it's the plant's first repot, more often than not the pot should be smaller than it's currently in; but again, that too pivots on your choice of grow media. and watering habits.

BTW - don't think you have run out and buy a pot with multiple drain holes. One DH is all you need. If you have 2 pots, one with a single half inch DH and the other with 10 or even 20 half inch DHs, if all else is equal, both pots will hold the same amount of water when they stop draining. The one with 20 DHs will stop draining a minute or two sooner, but the amount of water remaining in the soil will be the same. Reason: Water retention is determined primarily by the size of the particles that make up the grow medium and whether any internal pores in the particles are open or closed. The water that's best avoided is the any water held in the inter-particulate spaces - the pore space between soil particles (perched water). That is what primarily limits oxygen supply to roots of containerized plants and as a result it limits root function. Soil compaction is also an issue with plants because the compaction of the particles squeezes air out of the small pores between soil particles, which is primarily a problem associated with fine-textured media.
Al

Its always good to get more than one perspective on a problem/question. One size answer does not fit all types of plants. Cactus and succulents are always the outliers on care. Read the advice carefully and choose what will work for you and your specific plant.

If you read carefully, you'll see it's me disagreeing with one-size-fits-all advice and qualifying what I say so people can understand the reasoning and science behind the advice. I've found that people appreciate more than one perspective when all parties support what they say with things like facts/ science/ logic. Disagreeing just to be disagreeable, and not supporting what we say in disagreement to arrive at an opinion really isn't helpful. You disagree with me so often, if I were to say, "You should only attempt to jump that 20ft chasm in a single bound", I expect you would insist it should be done in two.

Al

No need for personal attacks especially as we seem to be agreeing. Have a nice day.