Pot Size for Draceana marginata

I'd like to get the fastest growth possible from my little Draceana, and I'm wondering what the best pot size would be for that.

It's about a foot tall and came in a puny pot - maybe 3.5 inches wide by 4 inches tall, and very peaty soil. I have plenty of sun for it with a south-facing window and balcony, and it's already adapted to several hours of direct sun daily. It does have just one lower leaf on which just the end 1/2 of the green has turned deep yellow. Oddly, the red edge hasn't changed. It's quite pretty, but I doubt it's normal (unless this is how it normally drops those lower leaves). I think it needs, or would at least benefit from, a larger pot and healthier potting medium.

So, what size and shape pot, and what sort of mix do you Draceana experts suggest? :-)

Looks good. Nice spider plant flowers, too! The sticky article at the top of this forum should answer most of your questions.

Dracaenas are known to be sensitive to tap water chemicals that can't evaporate if the water sits. For that reason, many try to use rain, distilled, when possible, for these plants.

Move it up into just the next size up pot. Sounds like it is in a 4" pot now, so a 6" would be good. Mine was the same, and I put it into a 6" clay pot. The clay breathes better, and is heavier, so it does not fall over so much.

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 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. 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) 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 (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 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 why the oft repeated advice to ‘resist pottting up more than one pot size at a time’, only applies when using heavy, water-retentive soils. Those using well-aerated soils 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

A six inch pot will do just fine. Once it has doubled in size you can go bigger if you want. These plants can get quite large in a small container so there is no need to rush.

Kwie - one of the first notable symptoms of root congestion is a reduction in extension of stems and branches, so if you want to maximize growth, the largest container you're comfortable with is going to serve you best in attaining that goal. If you do chose to utilize a large container, your soil choice becomes very important. You can easily over-pot if you use soils based on small particles (peat, coir, compost, composted forest products, sand, topsoil, .....). The key is to use a soil that doesn't support a soggy layer of saturated soil at the bottom of the pot. With a soil like that, over-potting is just a word, and the fastest growth can be achieved.

Al

Not to contradict anything Al just said, I don't think pot size matters much for this plant. As for my own growing, I prefer to repot regularly so I am aware what's happening with the root mass over time, rather than drive growth in huge pots from day one.

... and let me emphasize again that growing in what most would consider an over-size pot is only for those using a soil that doesn't support a soggy, airless layer at the bottom of the pot.

If a grower stays on top of root pruning, he can get excellent results in smaller pots, but once the root/soil mass gets congested to the degree that the root/soil mass can be lifted from the pot intact, growth and vitality will be negatively affected from that approximate point in time forward; and once that occurs, nothing will relieve the limitation except root pruning. He might see the plant exhibit what most would consider a growth spurt after potting up, but that 'spurt' isn't a spurt at all - only the plant temporarily returning to a growth rate that is only slightly closer to its genetic potential than it was before the potting up. In essence, it's the plant showing him part of what he'd been missing all along.

Baja - I didn't forget about taking the picture of the dwarfed A. arborescens. It's on my phone. I just need to take the time to move it to where I can get it posted. I hope the OP forgives the cross-talk.

Al

This effect is quite small for many succulents (mostly what I grow) in the range of 6 months to 2-3 years. A root bound state is in fact desirable for many of them, mainly for reasons of space and economics. You can fit more plants in a given space over time if you keep them in as small a pot as they will enjoy. Given this constraint, and to minimize my water usage, I am always trying to economize. I have become aware of the limitations. You can't do it this way if you don't stay on top of the plant's needs as it grows. There's way more juggling, and slower growth overall.

Looking forward to see any and all dwarf oddities!

It's good to recognize there are 2 distinctly different perspectives when discussing growing. One involves what is good for the grower or what end the grower wants to achieve, the other involves what's good for the plant or what the plant would want if it could tell you. The important thing is knowing that tight roots have a negative effect on growth and vitality. That knowledge shouldn't invite a judgment if one uses it to a specific end; rather, it should empower the grower to better determine how much in the way of growth and vitality it's wise to sacrifice to achieve that end. Two common ends that can be achieved via the stress of growing plants tight are in some cases a slightly greater abundance of blooms and/or more compact growth - shorter internodes and smaller leaves.

I had a very old Madagascar palm that I gave to Matthai Botanic Gardens in MI. It was interesting because its spines told a story. Looking at the vertical distance between the spines, you can see every time I repotted the plant. The spines would become more and more vertically compressed each year that passed w/o a repot. After a repot at maybe a 5 year interval, the distance between spines immediately stretched out to at least 4-5 times the vertical distance between them than there was at the end of the 5 year stint w/o repotting. It's a story written in the spines on the outside of the plant just as clearly as the words on a page. The plant was about 3.5 ft tall when I gave it away, but had I repotted it more frequently it might easily have been 2X that ht. I didn't repot it more often because it's not a fun plant to repot. ;-)

Al

Whether or not long internodes are "good for the plant" in the case of Pachypodiums I will leave up to others to decide. I prefer to keep them short and spiny, maybe just "good for the grower" but I suspect also tougher in the end. Here's one example where the spines tell a story... guess when I took over the care of this plant. It flowered continually all through the summer so I don't think it's been suffering unduly.

I hear what you're saying, though. The tension and release of the repot cycle are to be respected.

Please forgive the detour(s) off topic, I find it very interesting to share these experiences. Thank you for your comments, Al.

Oops, the picture.

Oops, I'd neglected this thread. Got distracted repotting. :-D

It's in a very large pot in grit now. It was pretty tight in the old one. I'll be interested to see how it grows, but with nothing for comparison, it'll be hard to judge whether the large pot and grit are any nether than a small pot with soil. I thought about buying a second Draceana, but I only have room for so many plants. I will eventually experiment with some faster growing species to see for myself what effect different media have.

Thanks for the info, guys, and the different perspectives.

For the size that plant is, I wouldn't consider the pot large at all. After you've repotted a few times, you'll see how big and fast the roots grow.

In the first pic below, a group of small trees I just repotted, back into its' same pot, after trimming the roots fairly aggressively, as I do whenever I repot them. Usually about once per year.

The 2nd pic is a tree that I've skipped repotting this year because it's in a much larger pot, and I recently removed a much taller trunk (to both serve as a cutting to make/be a new tree, and because it was too tall for my style of potted plants.) The growth at the top seen in the pic started growing on the stump a few weeks after I removed the older, taller top. (And all of the little trees in the 1st pic used to be parts of the larger tree.)

My plants are outside most of the year, most of them sitting where they can be rained on. If the soil rots the roots when/if it stays moist, that would be a death sentence for most of my plants.

A mix like that in your pic (or anything chunky, that can't wick moisture sideways or up - like 'cactus' or 'orchid' mixes,) can be a little strange to get used to, for those using something like that for a first time. Moisture will only fall straight down, so it's necessary to sprinkle the whole surface well to deliver moister thoroughly, to all parts of the root ball, and to make sure it escapes both the pot and drain saucer. (You'll probably need to add too much excess water for a drain saucer to catch anyway, to moisten all parts thoroughly. I take plants to sink/shower for watering for that reason.)

This message was edited Oct 27, 2014 10:26 AM

The grit isn't entirely new to me. I was growing pothos and succulents in pumice first. They did fine - pothos seemed to really like it. I am watering my grit plants by submerging the pots in a bucket until the water reaches the top of the medium. Some have too much foliage to be able to water from the top without getting the foliage wet. I lost a leaf on an Aloe most likely from top watering the grit. For pots too large to dunk, I have a narrow nozzle watering can that I fit into the foliage between stems. The difficulty in soaking the entire medium is one of the things I don't really like about grit.

Are you using something like 5-1-1, purpleinopp? On my very small phone screen, it looks a lot like straight bark. I was thinking of experimenting with a more organic grit - like mostly bark.

How fast does your D. marginata grow? We're in very different climates, but I've had this plant before, and it's never grown fast (I've lived all over the country though and dont remember which states i was in). I am trying to decide whether it would prefer cooler temps outside with more sun, or slightly warmer inside with less sun.

Don't forget your nutritional supplementation. With soils that are largely mineral-based, it's important to be sure you fertilize regularly or your plants will stall. It's also important to use a fertilizer that furnishes all the nutrients plants normally absorb via the root system. You'll go a long way before you find a fertilizer better than Foliage-Pro 9-3-6 as your 'go to' fertilizer for virtually all your plants. I use it for everything I grow, and only supplement it for a couple of plants - tomatoes and hibiscus.

Al

I totally dropped the ball fertilizing this summer, too many mosquitoes for me (plants all outside for summer.) TY for the reminder, Al.

Kwie, these are generally slow growing as potted plants, their potential pace is rarely seen in a pot. Doubtful that I have, even though I've seen my trees grow faster at some times than others. For anyone to say something specific, like "x" inches per year, there will be tons of people disagreeing (because their plants did something different.)

The important things to gauge (more so than speed of growth) are that new leaves are being formed at least as fast as older ones are being discarded, and that the newest leaves on the top are upright. If either of these factors is not the case, please investigate why. (It's normal for the oldest (bottom) leaves to be discarded as the plant ages.) Another thing to look for would be yellowing tips. Various chemicals found in some tap water can make Dracaena (and many other) plants ill. Whenever you are able to use distilled (not bottled drinking,) rain, or condensate from a dehumidifier or A/C, your plant will appreciate it.

That particular pot of the little crowd of trees has some home-made stuff that I don't expect to last past spring. But yes, it has a lot of bark in it. I've tried the kind of mix you describe, liked it well. Plant budget is currently called home improvement budget though... so some improvising (being plant-cheap!) is happening. NOT a recommendation, risks abound, just answering your question.

My mix these days is half pumice (screened) and a quarter coir (larger fibers) so it's pretty free draining. I have not experienced any issues related to wicking of moisture, probably as these materials both absorb water. Regular cactus mix (the barky type) has not presented any issues either for the same reason. More an issue (in my experience) is the need for regular watering as the soil goes dry quite fast compared to regular potting soil. And when you water, you need to really be sure you've saturated the soil. Organic matter that goes dry will often require two passes (separated by a few minutes) to fully rehydrate. That is actually my default.

Our tap water comes from underground and it has a lot of stuff in it that some plants don't enjoy. Drinking water (purified but not distilled) is dramatically better for those plants, so I use it for baby seedlings. Both our tap water and the purified water come out very alkaline (pH 8-9) so they benefit from a bit of acid to neutralize that. This sort of tinkering with aquarium chemicals is really unnecessary for the vast majority of garden situations (I would imagine) but for the dry-growing plants that I prefer, I think it makes a difference. A few side by side comparisons have been quite convincing.

That said, I'm sure the tap water in Cottage Grove is river or runoff water and the salt/alkalinity issues are irrelevant. These are not likely avenues that will give you faster growth. Like purple said, everyone's going to have an opinion based on their experience.

FWIW - a small RO filtration system for drinking water and watering plants can be had for around $200. I bought one a couple of years ago and it's still putting out water at 0 ppm any time I need it, so they're inexpensive to maintain.

Al

Coincidentally, it had an issue today related to its potting media. I watered it just a few days ago, and today I put it back out on the balcony for some afternoon sun. It wilted. It had only gotten maybe an hour to an hour and a half of sun, and it is acclimated to much more than that. It is only about 60 degrees outside, so heat isn't the problem.

It's been in the new pot and grit for 12 days. I would've thought that long enough to settle in. I stuck the grit with a bamboo skewer and it didn't come back very wet. I hope keeping it mouse enough isn't going to be s problem in this mix.

Al, I'm using Foliage Pro every time I water.

I need to change my profile. I moved away from Cottage Grove a couple months ago. I used rain and well water there. Now I'm on Eugene city water.

If your plant wilts while the soil is still moist, it's a near certainty you're over-watering .... especially if the plant seems to recover or partially recover during the dark cycle.

Al

Over-watering grit, Al? I don't think so. I think it isn't retaining enough water with this plant. The skewer wasn't wet when I pulled it out, and the plant never wilted in soil. Something about the grit needs to be adjusted so it holds more water, I think.

Did you mention how you made the soil?

Happy Halloween. Winds raging here and rain mixed with snow. We're not expecting to be mobbed!

Al

What's Halloween without spooky weather? Just another night.

The mix this one is in is 2 parts granite to 1 part DE. It's all been rinsed through mesh to remove silt.

If I don't feel it's holding enough water, I should increase the DE, right? I won't do it yet as the plant hasn't been in this for long enough for me to know how it likes it or what's going on, but if I do determine it needs to hold more water, how do I gauge how much more DE to add? DE is difficult to judge because it FEELS dry because most of the water is inside the particles. Granite wets on the outside, so it's simple enough. It does help that this DE is white when dry, and tan when wet though.

You will get better water absorption if you put some organic in the mix. Or use a porous material like pumice which can take up and hold a little water. I prefer a combination of the two. And you will see better water retention if you use top dressing, which slows down evaporation from above.

I will top-dress this plant. That's a very helpful observation. Thanks much, Baja.

I have some plants in 2:1 granite to diatomaceous earth, and others in the same mix plus 1 part screened pumice. I tested the ingredients first. DE takes up over 50% of its volume in water. Granite latched onto less than 20% (17%), if I remember correctly (don't have my notes out), and pumice held 23%, I think. I even dried the material out in the oven first to level the playing field.

I suspect the biggest difference might be how they release water. DE holds it deep within the particles where roots have to sort of work to get it out (hence "feeling" dry); granite keeps it on the surface where it's very accessible, and pumice holds much in tiny surface pores rather than deep inside, so it's somewhere between the two. I think I'd need a pretty accurate little gram scale to test how long each type of material holds the water, but that's my untested hypothesis for now. I will test it when I can afford a scale or come up with another idea. Meanwhile, I FEEL like the 2:1:1 mix is better, but that's totally subjective.

I have purchased a little bark and really want to make some gritty mix according to Al's recipe, but I need somewhere other than my new apartment carpet to screen it. Until then, I can only play with other media. I'll soon run a little experiment with about 6-8 different media and watering styles to see which of them works best. I'm still searching for good test subjects (want to try a couple different fast-growing plants). I'm a biologist, and just can't truly believe anything, including my own subjective observations, without empirical data. I will post observations and results as I go (if I ever get the test subjects). Meanwhile, I have my plants' various mixes marked, and I continue to try to make sense of it from my unreliable, subjective observations. ;-D. Mostly, they're all doing very well. I suspect I'm the only one who thinks any of them (except the C. tetragona that got mites) should be better.

Hey, Baja (or anyone), I'm trying to find good information on plant biology and physiology - things like exactly what the mechanism is that allows a plant to acclimate to sun exposure (the plant equivalent to producing melatonin); exactly what role various nutrients have; how/what affects leaf shape; why/how some plants grow larger leaves if supported, etc. It'll need to be in the form of used text books I can buy cheaply, or free/cheap internet info. Do you have any suggestions?

This message was edited Nov 3, 2014 7:42 AM

I like the way you're trying new approaches. Unfortunately in the process of figuring out what works, there is a fair amount of failure. As long as you don't get too attached, that's okay. I actually like to see some failure (ironically) because it means that I am testing the limits and learning what matters.

As for a reference guide, the only book I can recommend is one that focuses on my favorite plants, Park Nobel's Environmental Biology of Agaves and Cacti. It's data-rich (lots of figures) but I found the text user friendly. Most of the book is centered around how plants respond to changes in light, temperature, water.

Thanks, Baja. I'll look into that book. Appreciate it.