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aharriedmom

Choosing Correct Container Size. How? Why?

aharriedmom
11 years ago

** I am aware of potential issues with potting into a too large pot (see 3rd paragraph) - my primary question is in regards to knowing if a pot is/will be too small for a plant. This is information that I've searched the forum for but I'm either not using the right search terms or there just isn't a lot of information about it. I feel pretty confident that I'm just not using the right search terms, lol. I can't be the only one who has wondered about this.

As you might know, I'm new to houseplants. I've made up some gritty mix & 5-1-1 (waiting for my coarse perlite to make up more) and have repotted a few plants into the different mixes. I have several more that I plan to put into one of the two mixes but I'm unsure about pot sizes. Most of them are in the same size pot that I bought them in - 4". A few are in bigger pots (either that they came in or that I put them in) the largest is 6", not counting my peace lilies which are in larger pots.

Will I do the plants a disservice if I leave them in the 4" pots? How do I decide what size pot to put them in? I know that with the gritty or 5-1-1 I can put them into larger pots with no issues (except, perhaps, initially more frequent watering). I just happen to have a lot of cute small pots or cache pots and not as many bigger ones.

Right now I believe that if the plant's roots are filling the current pot, it ought to be potted up into a larger size. But what about the plants which might grow rapidly? Of course, except for a couple, I'm not entirely sure which of my plants would be/are rapid growers - but still...

I repotted the Dark Pittsburgh Ivy into gritty mix today. It had a little root system so I felt okay about putting it back into the 4" pot. We'll see how it goes!

Comments (43)

  • capoman
    11 years ago
    last modified: 9 years ago

    Container size matters. First of all, I know of no reason a large container would be an issue (except for cost or space) unless you want to deliberately keep the plant small. That is why bonzai tends to use undersize containers. In general, the larger the better, as keeping them in small containers actually increases watering and fertiliing frequency because of reduced buffering, and will tend to slow down or dwarf plants. If the plant isn't showing excessive roots or root circling, you are probably ok for now. Some say to judge container size based on matching size of above ground foliage, and I believe this is a good rule of thumb when you have fast growing plants, but plants that are mature will not need quite so much. Best test is still to pull out of the container and check root growth. Always tend toward overpotting rather then underpotting.

  • aharriedmom
    Original Author
    11 years ago
    last modified: 9 years ago

    Okay, thanks. So simple, really.

    So.... one more silly question - how would I use the foliage size to judge a pot? For instance, I have an arrowhead vine, pink butterfly Nephthytis, that is almost two feet tall but not very thick. Do I just imagine the top growth all "smooshed" down into a ball?

    -- I have a few plants that are potted into clear containers which are sunk into cache pots. I'm starting to lean towards believing that's much easier because I'll be able to see root growth without disturbing the plant. :D

  • calistoga_al ca 15 usda 9
    11 years ago
    last modified: 9 years ago

    When your plant out grows your pot size. you can tell as the pot will not be able hold sufficient water. The entire pot is full of roots and the water runs right through it. You notice the foliage wilting within hours of water being applied,instead of days. To keep it in the same size pot, the root mass will have to be reduced, as well as replacing the mix. Al

  • dickiefickle
    11 years ago
    last modified: 9 years ago

    You need to check for growing conditions for each individual species of plant .Generly a plants pot size increase only by 2 inches at a time ,4 inch to a 6 inch.
    However some plants need to be rootbound in order to bloom or cast out new shoots .
    If you dont know the name of a plant , posting a pic will usually get a correct reply.

  • aseedisapromise
    11 years ago
    last modified: 9 years ago

    Here's what I do generally. I think of the plant having about as much of a root system as it does top growth. So I try to provide enough space for that many roots. This can vary depending on what you are trying to do, and what kind of plant you have, what soil you are using, and so on. Some plants like tall containers, and some do better in wide squatty ones. It might even depend on if the container is say, terracotta or if it is plastic or glazed ceramic. Sometimes there are things that just have to come with experience. I just changed a lot of my plants to some of tapla's mixes, and I am having more learning to do even if I have been growing house plants for a long time. There's no shame in questions and none in just trying things and keeping notes on what happens. I just put a rex begonia in a pot that was "too big", it was doing poorly where it was. My thought was that the big pot would provide extra humidity for it, and since it grows kind of along the ground (rhizomatous), would give it room to grow if it should snap out of its funk and want to do that. It is doing much better than it was, and is growing now instead of dropping leaves. This was probably a plant that I shouldn't have bought, as it needs an environment that will be hard for me to provide. A really good book on house plants, (and probably you could check one out at the library) has a wealth of cultural requirements for plants. You can kind of get an idea if you need to provide something special for a plant by researching it, or if you shouldn't buy it in the first place, as in my case. Anyway, the rex will be okay for now, Not sure how it will like winter at my house.

  • TheMasterGardener1
    11 years ago
    last modified: 9 years ago

    dicklefickle,

    I agree.

    I hear that is a "horticultural myth" from the "pros" in the container forum. ;)

    What plants would like small pots to induce blooming?

    Maybe some could learn from this.

  • TheMasterGardener1
    11 years ago
    last modified: 9 years ago

    For some reason I thought this was a different forum then the container forum. :)

    I think cacti like smaller pots?

  • tapla (mid-Michigan, USDA z5b-6a)
    11 years ago
    last modified: 9 years ago

    Possibly pertinent to the conversation is why it's a myth that this or that plant "prefers" to be grown under root bound conditions.

    Here is a cut/paste job about what determines "appropriate pot size":

    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 soil. 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 parroted 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 soil will remain wet too long and cause root rot issues, but it is the size/mass of the plant material you are working with, and the physical properties of the soil 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 soil you choose.

    Plants grown in slow (slow-draining/water-retentive) soils need to be grown in containers with smaller soil volumes so that the plant can use water quickly, allowing air to return to the soil before root issues beyond impaired root function/metabolism become a limiting factor. We know that the anaerobic (airless) conditions that accompany soggy soils quickly kill fine roots and impair root function/metabolism. We also know smaller soil 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 soils 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 with a soil that is too slow and water-retentive. This is a key point.

    We know that there is an inverse relationship between soil particle size and the height of the perched water table (PWT) in containers. As particle size increases, the height of the PWT decreases, until at about a particle size of just under 1/8 inch, soils will no longer hold perched water. If there is no perched water, the soil is ALWAYS well aerated, even when the soil is at container capacity (fully saturated).

    So, if you aim for a soil composed primarily of particles larger than 1/8", there is no upper limit to container size, other than what you can practically manage. The lower size limit will be determined by the soil 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 very large containers if the soil is fast (free-draining and well-aerated) enough that the soil holds no, or very little perched water.

    I have just offered clear illustration that the oft repeated advice to 'only pot up one size at a time', only applies when using heavy, water-retentive soils. Those using well-aerated soils are not bound by the same restrictions.

    Al

  • TheMasterGardener1
    11 years ago
    last modified: 9 years ago

    Now I see why I was mixed up about "stress blooming". The plant will grow many many tiny little blooms if in a small pot. Funny thing is I forgot I even tryed this first hand by accident never thinking it related to this :) I had a house plant do this, when I planted it in a bigger pot and now it is bigger and way more healthy. So you could say I tryed stress blooming and seen what it did, nothing good for the plant at all. Tiny weak little flowers. Plants that have the right root space will grow the right sized blooms and the plant will be over all healthy. Same thing with a cherry pepper plant- it was in a 2 gal container growing fine and giving my nice sized peppers. Then a month later I noticed it was giving many little flowers and growing small little peppers that were pointless in size :)

    ^So, is that stress blooming? Because as far as plant health and production goes, stress blooming is not good. I was wrong for ever thinking it was good, of course :)

  • capoman
    11 years ago
    last modified: 9 years ago

    Thanks for clarifying that Al. My assumption that a larger container is better was certainly based on using a properly draining soil. Using a smaller container because a soil retains too much water is not a scenario I would consider, and to me would be the result of a bad soil choice.

  • tapla (mid-Michigan, USDA z5b-6a)
    11 years ago
    last modified: 9 years ago

    Exactly!

    Al

  • eryka_serrano
    7 years ago
    last modified: 7 years ago

    Hello Al..

    I'm planning to change to the fir bark 5:1:1 mix for my fiddle fig tree. Do you recomend a bigger container based on the pic below? The one in the picture is 15" tall.. With the 5:1:1 mix what size do you recommend?

    (Zone 8a)

    Also do you think I need to put a stack to hold the bigger branch (the right side)? I think it is too heavy and I'm not sure if it's strong enough.

    Please advice

    Thanks

  • eryka_serrano
    7 years ago

    Thank you Al for your advice. All I want is a big and beautiful tree. I must say that I have never done this before, and to tell you the truth I am a bit scared of doing it, however I will follow your advice.

    I do have a question though, should I cut all branches? If so, how much should I cut from each branch?

    Once I prune the branches, I do plan on repotting the tree and changing the soil to the 5:1:1 mix using fir bark. As I change the soil and repot, do you recommend I also trim the roots?

  • tapla (mid-Michigan, USDA z5b-6a)
    7 years ago

    If you haven't read this about maintaining trees in pots over the long term, it will be helpful.

    Also, this thread is how to reverse the trend of plants in decline or those just treading water.

    I'll be back later in the day to answer your questions. Work demands my attention at the moment.

    Al

  • eryka_serrano
    7 years ago

    Thank you.! I will read them.

  • eryka_serrano
    7 years ago

    Done.. I already read those posts you recommend. Thanks Al for all that information. Now I understand better what to repot really means.. Do you have a post regarding branches pruning? I still don't know how much I should cut from each branch..

    thank you Al

  • tapla (mid-Michigan, USDA z5b-6a)
    7 years ago

    You're welcome - my pleasure. Here's what I would do, and I prune this hard ALL the time - I would cut the top back to just above the first leaf above that little bare spot. That should force back-budding to produce branches on the trunk where it's bare. ALL other branches would be taken back to 2 healthy leaves. You can prune top now and do the repot in 2 weeks, or do the repot and prune in 2 weeks (actually when there is certain evidence the plant is pushing new growth in more than one location.


    Al

  • eryka_serrano
    7 years ago


    Al

    Thank you for your advice.


    I'm planning to prune it this weekend so I need a little more clarification on a couple of things—again, I am sorry this is my first time doing this and I want to do it right. You mentioned to cut where the little bare spot is; it seems that someone else had pruned it there and the new branch grew from there but it grew almost straight (see attached photo). Is there any problem if I cut almost in the same place?

    And as per the other two branches, just to make it clear, you are recommending I prune the entire branch and leave only 2 leaves per branch? I totally trust you, just want to be sure I understood well.


    Would I be able to plant the newly cut branches?


    As always, thank you so much for taking the time to help me, I'm sure you have answered the same questions over and over again.


    Erika

  • tapla (mid-Michigan, USDA z5b-6a)
    7 years ago

    Is there any problem if I cut almost in the same place? No problem. The new cut will force budding below. After that occurs, you'll be able to prune that swelling off by pruning just above a branch that's yet to occur.

    ...... just to make it clear, you are recommending I prune the entire branch and leave only 2 leaves per branch? Yes. You'll get a new branches from the crotch of each of the 2 leaves you left. After each of those branches grows 4 leaves, prune them back to 2 leaves. This will get your plant to where it's as full as it can be (within the limits of other cultural factors - tight roots cause shedding of old and inner leaves, as does nutritional deficiencies of the mobile nutrients.


    Yes, you can start the trimmings as cuttings. If you want a standard (1 trunk) leave the growing tip on the cutting. If you want a multi-stemmed plant, use an internodal cutting (remove the growing tip).

    It's true there's a lot of repetition in the questions asked on this forum, but my reason for being here is to help other growers gather knowledge and develop skills that allow them to get more from the growing experience. Since growers keep bumping into the same obstacles, the same questions re how to get around them are to be expected - goes w/the territory. The more we learn about how plants work and the best ways to get them to do what we want, the more reward we get for our efforts ..... and we all want rewards. I enjoy feeling/knowing that my contributions are helping, and the only thing that allows me to feel that way is the feedback I get about the comments I make.

    Al

  • eryka_serrano
    7 years ago


    Thank you Al

    I have two more questions.

    Regarding the two branches that should be cut back to two leaves, you mentioned in the previous email that they should be cut back to two healthy leaves. The two first leaves seem to be old and sagging, is that OK to cut there? Or should I cut a little further up where the leaves are healthier? Please see attached photo.


    Regarding the trimmings, do I just plant the trimmings without roots in a normal pot? Or, Is there a special procedure you recommend to help the trimmed branch start rooting faster?


    Do you have a blog of your own? If not you should. :)

    Erika

  • tapla (mid-Michigan, USDA z5b-6a)
    7 years ago

    You're ok to cut those branches back to 2 leaves.

    Cuttings like lots of air in the root zone, so choose a medium that doesn't support a tall perched water table and be SURE not to stick the cuttings so deep the proximal end will fall within that saturated layer that's virtually inherent in almost all commercial soils. Also, it's good to secure the cutting so it can't move in relation to the pot

    because movement breaks very fine roots and slows establishment. Use a very sharp tool to 'clean up' the proximal en of the cutting so there are no microscopic tag ends, which is where rot usually gets a hold


    Al

  • eryka_serrano
    7 years ago
    last modified: 7 years ago

    Thank you.!

    one more question.. Do I have to wound the base of the branch? Or that is just when you are going to use a rooting hormone?

  • tapla (mid-Michigan, USDA z5b-6a)
    7 years ago

    When you remove a cutting, the cut is all the wound you need. Just be sure you don't use a tool that will crush the tissues while cutting through them and don't forget to clean up the wound end by trimming carefully w/a straight edge razor blade or a new utility knife blade.

    Most growers think rooting aids are essentially the same, but the wrong rooting hormone can actually slow down or prevent rooting in plants for which the aid isn't appropriate. IBA is the appropriate choice for ficus, in case you're heading in that direction.

    Al

  • eryka_serrano
    7 years ago

    Thank you Al for share with us all your knowledge I won't use the hormone..

    Erika

  • eryka_serrano
    7 years ago

    Hello Al

    I finally pruned my tree today.. And I'm planning to repot next Sunday.. It's that ok wait just a few days to repot or should I wait two weeks?

    I have a couple of questions.

    do I have to put anything on the Clipped branches? Or do they heal by themselves? (Hopefully is not too late)

    Regarding the cuttings.. I put them 3" deep into the mix soil. Is that ok? How long does it take to start rooting? Are they going to lose the leaves? Do they need any special care?

    Here are some pics of the cuttings.. Let me know what you think and if you have any suggestion please let me know..

    thank you Al

  • tapla (mid-Michigan, USDA z5b-6a)
    7 years ago

    You can repot now.

    No need to dress the wounds. The stubs will die back to the first node below the cut. You can remove the stub later, and it should be removed when the tree starts to grow a collar around the stub. Then, cut the stub off flush to the collar.

    The cuttings should be buried at least 2 nodes deep. I'd leave only the 2 top leaves on the cutting, and I would cut them in half across venation (90* to the main leaf rib) to reduce transpirational water loss and to help avoid shedding of the leaves. Keep the cuttings outdoors in open shade and out of the wind.

    Anything else you can think of?


    Al

  • eryka_serrano
    7 years ago

    What's the percentaje for the cuttings to survive? Is it easy?

    How long should I leave the cuttings outdoor, until they start rooting? How do I know when they have roots? My question is because here in my zone the weather is everything but stable. Now it's really hot but some days really windy.

    Is it completely neccesary to remove all the leaves (except for the 2 top leaves )for the cuttings to survive?. For the shortest cuttings I would like a standard 1 trunk form, not a tree form so the lower side will be bare.. also to remove the leaves, do you recommend to cut them or just remove them with the hands?

    I just change to the fir bark 5:1:1 mix. How different are the water habits are from the commercial soil ? I was watering every 10 days but now they will be outdoors so I don't want to kill them.

    Sorry if I didn't explain my questions very well.. English is not my primary lenguaje.

    Thank you for all your time and your guidance.!

  • tapla (mid-Michigan, USDA z5b-6a)
    7 years ago

    What's the percentaje for the cuttings to survive? Is it easy? %s are high if procedures used are appropriate, which sort of means that knowing what to do and not to do are big factors in determining success. It's not considered a 'difficult to root' species.

    How long should I leave the cuttings outdoor, until they start
    rooting?
    I'd leave them out as long as temps are appropriate and weather conditions allow. How do I know when they have roots? If you avoid tugging on them, as you should, the only real way to tell is when the second generation of leaves are forming, though you can be 99% sure well before that on plants with leaves as large as lyrata. My question is because
    here in my zone the weather is everything but stable. Now it's really
    hot but some days really windy.
    Hot is fine if cuttings are in open shade, but windy isn't good. They should be in a spot protected from wind.

    Is it completely neccesary to remove all the leaves (except for the 2
    top leaves )for the cuttings to survive?
    It's good practice, but you won't know the answer to that question until you succeed or fail. For the shortest cuttings I
    would like a standard 1 trunk form, not a tree form so the lower side
    will be bare.. also to remove the leaves, do you recommend to cut them
    or just remove them with the hands?
    I didn't understand the first part of what you said. Could you rephrase? ALWAYS remove leaves above the soil line by snipping through the petiole (leaf stem) with a pr of scissors or other tool and let the petiole fall off naturally. Pulling the leaves off with your hands can damage axillary buds and prevent new branches from forming where they normally would.

    I just change to the fir bark 5:1:1 mix. How different are the water
    habits are from the commercial soil?
    It depends on how large the bark you used is. If you used Reptibark, it might be a good idea to include a measure of material that adds a little more water retention. Options would be Turface, calcined DE, vermiculite as a last resort..... You'll prolly need to water every 5 days or more often.

    Sorry if I didn't explain my questions very well.. English is not my primary lenguaje. Don't worry. No one expects perfection. You're doing fine.

    Thank you for all your time and your guidance.! My pleasure.

    Al

  • eryka_serrano
    7 years ago

    Yes. I used reptibark. I'm going to order turface online since it's not available in my area. It is just one measure of that, rigth?

    should I put the cutting in water while adding and mixing the turface to the soil mix?

    Regarding the root pruning.. I should cut 2/3 of the root,rigth?

    thanks again.!!'

  • tapla (mid-Michigan, USDA z5b-6a)
    7 years ago

    Where do you live?

    If you have cuttings, it's not a problem if they aren't potted up immediately, but you can't leave them lie around for hours & hours w/o a moisture source. If you had to, you could wrap the base of the cutting in wet paper towels or an old newspaper overnight or even for a day or two.

    I would suggest you start off on the safe side when it comes to root pruning. I'd remove the bottom 1/3 of the root mass, bare root, then correct any problem roots and call it good until the next time the plant needs a repot, which would be in 2-3 years in most cases.

    Al

  • eryka_serrano
    7 years ago

    I live in El Paso , Tx. Zone 8a

  • eryka_serrano
    7 years ago

    Hi Al

    Should I also add the turface to the reptibark mix for the tree that's indoors, or just for the mix of the cutting that are outdoors

    thanks

  • eryka_serrano
    7 years ago

    Should the turface be the MVP ot the quick dry?

  • tapla (mid-Michigan, USDA z5b-6a)
    7 years ago

    I grow all my houseplants, succulents, trees I'm growing on for bonsai, and all my bonsai in the gritty mix. There are a very few plants I'd prefer to grow in the 5:1:1 mix over the gritty mix but there are no trees among them.

    Don't pay the long dollar ordering Turface MVP online. You'll find it here:

    Al

  • eryka_serrano
    7 years ago

    So for the ficus lyrata is also better the gritty mix than the 5:1:1? I was totally focused in get the ingredients for the 5:1:1 mix.

    the gritty mix is 1:1:1 using turface, pine bark ( reptibark in my case) and granite.. Correct? I will look for the granite in the area.. Does it have any other name? Is it common to get it in the nurseries?

    thank you for the info to get the turface cheaper.. I really appreciate it..

  • tapla (mid-Michigan, USDA z5b-6a)
    7 years ago

    Either mix if made correctly will suit the plant just fine. If you read the thread about container soils and how water behaves in container soils, you'll realize that as long as the soil embodies the concept behind the soil, you're in good shape, Essentially, the soils build lots of air into the medium and support little to no perched water (that soggy layer at the bottom of pots when soils comprised of large fractions of fine ingredients). In your area, you might only be able to find Manna Pro Poultry grit, but as you call around, also ask for Gran-I-Grit in grower size or #2 Cherrystone. Any of those 3 ingredients work very well with Turface to give you adjustment over how much water the soil holds. You'll find the crushed granite at feed stores or grain elevators that cater to rural keepers of fowl.

    Al

  • eryka_serrano
    7 years ago

    I found these two.. Are they ok for the mix?

    thanks

  • eryka_serrano
    7 years ago

    I finally have all the ingredients to repot my ficus lyrata.. Thank you for all your tips on getting the material. It was easier with the information you provide me.

    Based on the ingredients sizes. Will the ratio be 1:1:1 ?

    Thanks

  • tapla (mid-Michigan, USDA z5b-6a)
    7 years ago

    Because the bark is so large, I'd probably go 2 bark, 2 grit, 3 screened Turface.

    Al

  • eryka_serrano
    7 years ago

    This is my mix 2:2:3 as suggested.. Should it looks like this?

    It's difficult to mix it because of the different sizes..


  • tapla (mid-Michigan, USDA z5b-6a)
    7 years ago

    Ideally, the bark would have been about half its current size, but what you have will work well. Adding the soil to your pot by scoops instead of pouring it should help to get it mixed toward the bottom of the pot. It won't matter a whole lot if some of the bark toward the top works its way to the surface. Even though water will make it's way downward through the soil quickly, water slowly to disturb the soil as little as possible, which will help reduce stratification of the ingredients.

    Al

  • eryka_serrano
    7 years ago

    Thank you for all your advice.!! I'm going them to trim the roots to repot my tree. By the way I think the cuttings are diying. :( the gren part of the stem is wrinkled. I think because the mix soil was incorrect. I use the 5:1:1 but the bark is too large and i didnt modified the ratio..also i don't have them outdoor because of the wind.. Do you think i'm on time to save them if I use the new mix. Or is it too late?