The initial symptoms of poor root conditions are progressive diminishing of branch extension on plants that branch, loss/shedding of foliage on the parts of branches nearest to the ‘trunk’, often giving the plant a ‘poodle look’, and reduced vitality. As rootage becomes continually compressed and restricted, branch extension stops and individual branches might die as water/nutrient movement is further compromised. Foliage quality may not (important to understand) indicate the tree is struggling until the condition is severe, but if you observe your plants carefully, you will find them increasingly unable to cope with stressful conditions - too much/little water, heat, sun, etc. Trees that are operating under conditions of stress that has progressed to strain, will usually be diagnosed in the end as suffering from attack by insects or other bio-agents/disease while the underlying cause goes unnoticed.

I will mention again that I draw distinct delineation between simply potting up and repotting. Potting up temporarily offers room for fine rootage to grow and do the necessary work of water/nutrient uptake, but these new roots soon lignify, while rootage in the old root mass continues to grow and become increasingly restrictive. The larger and larger containers required for potting up & the difficulty in handling them also makes us increasingly reluctant to undertake even potting up, let alone undertake the task of repotting/root-pruning, which grows increasingly difficult with each up-potting.

So we are clear on terminology, potting up simply involves moving the plant with its root mass and soil intact, or nearly so, to a larger container and filling in around the root/soil mass with additional soil. Repotting, on the other hand, includes the removal of all or part of the soil and the pruning of roots, with an eye to removing the largest roots, as well as those that would be considered defective. Examples are roots that are dead, those growing back toward the center of the root mass, encircling, girdling or j-hooked roots, and otherwise damaged roots.

I often explain the effects of repotting vs potting up like this:
I will rate growth/vitality potential on a scale of 1-10, with 10 being the best. We're going to say that plants in containers can only achieve a growth/vitality rating of 9, due to the somewhat limiting effects of container culture. Lets also imagine that for every year a plant goes w/o repotting or potting up, its measure of growth/vitality slips by 1 number, That is to say you pot a plant and the first year it grows at a level of 9, the next year, an 8, the next year a 7. Also imagine please, we're going to go 3 years between repotting or potting up.

Here's what happens to the plant you repot/root prune:
year 1: 9
year 2: 8
year 3: 7
repot
year 1: 9
year 2: 8
year 3: 7
repot
year 1: 9
year 2: 8
year 3: 7
You can see that a full repotting and root pruning returns the plant to its full potential within the limits of other cultural influences for as long as you care to repot/root prune.

Looking now at how woody plants respond to only potting up:
year 1: 9
year 2: 8
year 3: 7
pot up
year 1: 8
year 2: 7
year 3: 6
pot up
year 1: 7
year 2: 6
year 3: 5
pot up
year 1: 6
year 2: 5
year 3: 4
pot up
year 1: 5
year 2: 4
year 3: 3
pot up
year 1: 4
year 2: 3
year 3: 2
pot up
year 1: 3
year 2: 2
year 3: 1

This is a fairly accurate illustration of the influence tight roots have on a plant's growth/vitality. You might think of it for a moment in the context of the longevity of bonsai trees vs the life expectancy of most trees grown as houseplants, or the difference between less than 4 years versus more than 400 years, lying primarily in how the roots are treated.

I have not yet mentioned that the dissimilar characteristics of the old soil as compared to the new soil when potting-up also carries the potential for trouble. With a compacted soil in the old roots and a fresh batch of soil surrounding the roots of a freshly potted up plant, it is nearly impossible to establish a watering regimen that doesn't keep the differing soils either too wet or too dry, both conditions occurring concurrently being a limiting factor and the rule rather than the exception.

Most who read this would have great difficulty showing me a containerized plant that is more than 10 years old and as vigorous as it could be, unless it has been root-pruned at repotting time; yet I can show you hundreds of trees 20 years to 200 years old and older that are in perfect health. All have been root-pruned and given a fresh footing in in new soil at regular and frequent intervals, the same treatment all my houseplants get.

Thanks to any/all who made it this far. This is only an overview, but with even a rudimentary understanding of how to go about reducing the effects of the limiting factors that restrict growth and vitality, I know you can improve on how well your plants can grow, as well as on the degree of satisfaction you get from your growing experience - my only reasons for writing this. Hopefully the offering leaves you with many questions.

Al

You might find this link to More Information About Container Soils helpful.

Yeah Thanks for reposting Al!

I RE clipped them or I guess Bookmarked them

Hi Al

I am from Western Australia and am the proud owner of 2 indoor fiddle leaf figs who are growing nicely with leaves openingout from the bud at the top and also growing out of the stem at the bottom.

But I am a newbie with not much idea!!

They are both single stem and about 50cm tall. We are heading towards the start of Autumn but they both seem to be growing still.

I am wanting to encourage branching and was wondering if it is ok to cut off the current bud (once the new leaves are a bit stronger - they only opened a couple of days ago) now or if I should wait until Spring (September in Aus).

They are currently in 20cm pots so I was going to look at repotting them in Spring but was wondering if I should prune the bud now or wait as well.

Thanks for any help you can give!

Cheers

Kirsten

You can tip prune a healthy plant almost anytime, but you'll get a much more vigorous response (and the tree will backbud further back [proximal] from the pruning cut) if you undertake the exercise when the plant has lots of energy reserves and is growing with some enthusiasm. IOW - in the summer. If your winters are pretty mild and days don't get horribly short, you could probably do the pruning now w/o anything like a notable setback.

I don't do much pruning after Aug 1, but we have hard, dark winters (-16c now, going down to -26c tonight). For you, that cutoff would be Feb 1, but may not apply if your winters are mild.

Late spring is when I repot Ficus (except F carica - hardy fig, which I repot at onset of bud movement in spring). For you, I'd say after the plant has recovered from any winter doldrums and has started to push robust growth would be a good time to repot, with any heavy pruning to follow the repot by a few weeks - after growth has resumed.

Al

Hi Al!!

Like Josh has mentioned, I also think this is a great thread for beginners as well as experienced growers. Always room to learn no matter how long we have been working with our plants and trees!

I'm just thrilled that you reposted this awesome thread!

A favorite of mine as well!! ( hi josh!)

Take care,

Laura

Hey, Laura! Is the weather any better for you?

Josh

Hi Josh!!

It's been a cold and strange winter.. Lets just say the city has shut down today. We are expecting 10 inches of snow tonight and tomorrow.

Hope all is well.. It's not what Mike and Al have had, but we are at the beach.... Hurry spring!! ;-)

Take care,

Laura

Thank you for reposting this Al! I clipped this from the old GW and couldn't find it! :( so glad you reposted it! :)

Thank you - it's kind of you to say so, and I appreciate the effort.

Al

tapla (mid-MI z5b-6a)—Super helpful information. I have a question about fertilizer, as it wasn't clear to me. If I have a good mix of the proper soil that allows for drainage, air, etc., why would I also need fertilizer? In the same explanation you said that you could grow a perfectly healthy plant in a bucket of broken glass on a dare, assuming that composition will allow for proper air circulation. If this is possible, why even fuss with fertilizer? How do you know/can you tell if a plant, during repotting, even needs fertilizer?

Wait, nevermind. I'm now digging into this. D'oh! http://forums2.gardenweb.com/discussions/1389454/fertilizering-containerized-plants-iv

Plants can rob some nutrients (N, P, & K, for example) from existing tissues and use them to make new cells, so it LOOKS like the plant is growing. Some nutrients are locked up tight in tissues and can't be borrowed (Ca and most of the minor nutrients are examples) to create new cells. These nutrients must be in the soil solution and the plant's nutrient stream at all times if the plant is to grow normally. If your plant is producing new leaves and branches are extending, it still may not be growing. Growth is measured by the amount of increase in the plant's dry weight. If the plant is borrowing nutrients from other parts and shedding the parts after it cannibalizes them, the appearance of growth would be an illusion.

Nutrients aren't food for the plant. Sugar is the plant's food and it makes it itself during photosynthesis. Nutrients are the building blocks plants use to grow, and to keep their systems running in orderly fashion. Because plants can't absorb the hydrocarbon chains that make up soil particles, you would have to depend on soil organisms to cleave those chains so nutrients are available in elemental form the plant can use. The problem is, pots are usually very inhospitable environs for micro-herd populations, so they (soil life) can't be relied upon to provide a regular or sufficient supply of nutrients. Enter fertilizer.

No matter what a person's ideological view is when it comes to soluble synthetic fertilizers, they're easiest, and offer the most control and reliability. When it comes to container soils, concentrate on structure. When it comes to a soil's ability to feed the plant - forget it - that's what fertilizer is for, and it makes no sense to sacrifice a soil's structure for the sake of a few nutrients that any of a hundred fertilizer packagers can provide much more reliably than the soil.

I see you found the fertilizer thread. If you have questions, you can ask there or here.

Al

This has been the best educational reading material I have ever came across. I read the one you sent me a while back and it has completely changed my focus regarding my babies. =) Thank you for your love of sharing knowledge with others. You rock, Al.

~Gabe

What a nice compliment. Thank you.

I think helping others allows us to vicariously share not only in successes and accomplishments, but also in that overall injection of verve that comes when everyone is enthused and looking forward to fresh possibilities. I honestly don't think there is anyone here for purely altruistic reasons; we're all feeding on one thing or another. When we stop 'getting' from the experience, we find something else we can 'get' something from. In the end, I'm just as selfish as the next guy. ;-)

Al

Verve. haha you and your Words! I love that you make me look up words with almost everyone of your posts. The learning never stops!

~gabe

Would you rather I had used 'vim'?

Think about this for a second: No one has ever called me sesquipedalian before.

Al

Monosyllabic words are so drab. Your gift of words give your posts a prodigious piquancy.

hello Al (and all!)

I have been lurking around the container gardening forum for a while, mostly to read your posts, and i have signed up today to ask you a few questions:

1- Suppose the containers i'm working with are tall (deep) enough so that the pearched water table (PWT) phenomenon is irrelevant. Also, suppose the containers are additionally wide, so no root crowding would occur for the type (and desired size) of perennials i'm growing. Would container gardening, in this case, be closer to conventional (landscape) gardening than hydroponics gardening?

2- SPECIFICALLY, with tall/wide containers, and controlled size of the plant, would I have to repot every couple of years if I want a long life (say 10 years) for my perennials? Or would it be OK to keep it in the same soil for many years?

3- I read elsewhere that adding *certain* organic materials/ammendments to the soil (leaf mold, worm castings, organic fertilizers like alfalfa pellets, etc) is encouraged, in part, for the soil food web they build which tends to clump fine soil particles togeather increasing both aeration and drainage (as opposed, for example, to synthetic fertilizers which tend to *errode* soil). You, on the other hand, seem to offer a different perspective (organic materials decompose to fine particles clogging up soil pores), but if your answer to my question#1 above is yes, then would you recommend i keep using organic ammendments/fertilizers?

4- You wrote something along the lines of: plants are as strong as the weekest link. Where I live, I believe the most limiting factor is the inferno we try to grow our plants in! During June/July/Aug most plant growth comes to a grinding halt and chlorosis/partial defoliation is common for many plant species. Even the toughest plants (e.g. Bougainvilleas) grow very slowly, putting out puny leaves. To put things in perspective, during the summer months, temperatures hover around the 100-110 degrees ALL DAY LONG, with relative humidity of 10-15%. So wouldn't you agree that having to grow our plants in hell for 3 months of the year is more of a limiting factor than a less than ideal aeration/drainage? Riyadh's summers are so punishing to our plants that we have *TWO* Spring seasons: Spring Minor (from mid Sep to mid Nov) and of course the regular Spring time (Spring Major, mid Feb to mid May).

Thanks in advance, and i appreciate any input from other members as well.

--The Accidental Gardener.

Welcome! I'm happy you found some value in the things you read. If I say something below that seems to be in disagreement with what you said, please consider it an explanation rather than a correction.

1- Suppose the containers i'm working with are tall (deep) enough so that the pearched water table (PWT) phenomenon is irrelevant. Also, suppose the containers are additionally wide, so no root crowding would occur for the type (and desired size) of perennials i'm growing. Would container gardening, in this case, be closer to conventional (landscape) gardening than hydroponics gardening? As both the ht of the container and the volume of soil that occupies space above the maximum ht of the perched water table increases, the o/a limiting effect of perched water diminishes; but, PWTs really never become irrelevant because they will always limit the function of roots that colonize the fraction of medium that holds perched water.

What divorces container culture from growing in the earth and sets it closer to hydroponics is the fact that water acts differently in containers than in containers primarily because the absence of the earth to serve as a wick; and the fact that the way we water containers is remarkably similar to ebb/flow hydroponic growing. There are also many differences in things like the buffering capacity of mineral soils vs container media, micro-organism populations, the difference in the earth's ability to ameliorate rapid changes in many cultural conditions that affect plant health and growth - pH, temperature, moisture levels, nutrient concentrations, ..........

If, on a scale from 1-10 with growing in the ground being a 1 and hydroponic growing being a 10, we allow that conventional container culture is a 7 or 8, I don't think that what you described would appreciably change that 7 or 8 comparative relationship by as much as .5. What would change it much more is using the container as a raised bed (from the perspective of hydrology) - connecting it to the earth, so to speak.

2- SPECIFICALLY, with tall/wide containers, and controlled size of the plant, would I have to repot every couple of years if I want a long life (say 10 years) for my perennials? Or would it be OK to keep it in the same soil for many years? At about the time root congestion reaches a point where the root/soil mass can be lifted from the pot intact, growth and vitality is being limited by root congestion, and will become progressively more limited as time passes. Potting up can briefly help the plant realize more of it's genetic potential, but the practice always ensures the limitations remain, even if partially ameliorated. Repotting, with root pruning, eliminates the limitations entirely until such time that root congestion again reaches the point where the root/soil mass could be lifted from the pot intact.

To a trained eye, the effects of root congestion can immediately be seen by noting the distance between leaf bundle scars on some plants. Often, it's apparent how many times a plant has been repotted, and when (the year) it was repotted can often be seen in clues the plant wears as evidence.

3- I read elsewhere that adding *certain* organic materials/ammendments to the soil (leaf mold, worm castings, organic fertilizers like alfalfa pellets, etc) is encouraged, in part, for the soil food web they build which tends to clump fine soil particles togeather increasing both aeration and drainage (as opposed, for example, to synthetic fertilizers which tend to *errode* soil). You, on the other hand, seem to offer a different perspective (organic materials decompose to fine particles clogging up soil pores), but if your answer to my question#1 above is yes, then would you recommend i keep using organic amendments/fertilizers? First, I'm going to say that synthetic fertilizers don't erode the soil. I don't expect you to just take my word for that, so if you want me to expand on that thought, I'll offer up something I wrote about synthetic vs organic fertilizers.

I'll qualify what I'm about to say by stating I'm driven by results, and not by any particular ideology, so I'm completely unencumbered when it comes to choosing what works best in containers. About 90% of the plants I grow are grown with their appearance in mind and I want as much control over as many aspects of their growth habit and appearance as possible. I achieve some of that via pruning, but control of nutrition is also a very important part of growing an attractive plant. There is simply no comparison between using what are essentially organic soil amendments (like the leaf mold, worm castings, organic fertilizers like alfalfa pellets, you mentioned)to furnish nutrients as opposed to nutrients in synthetic form. In the end, the nutrients taken up are exactly the same no matter if they came from a box or a dead fish. If fertilizer was plant food, it could be said that a plant's diet consists of salts. Synthetic fertilizers allow complete control over what plants get, when they get it, the ratio at which it's supplied, and how much they get. Organic fertilizers used in containers get at best an erratic rating in each of those categories.

So, because it's easiest, most foolproof, most effective, and easiest to control, I use synthetics in containers. In keeping with the thought I like easiest and best, I adhere pretty tightly to making sure my soils in beds and gardens are doing the feeding. I supplement VERY infrequently in open ground - not bound by ideologies.

4- You wrote something along the lines of: plants are as strong as the weekest link. Where I live, I believe the most limiting factor is the inferno we try to grow our plants in! It very well could be - probably is, but not always. At any given time, there is one most limiting factor. Liebig's Law of the Minimum was originally conceived as a way to explain the nature of nutritional limitations. It said that at any given time it is the nutrient most deficient that limits growth and vitality. Eliminate that deficiency, and the next nutrient that is most deficient is what limits growth and vitality. The law of the minimum has been expanded to include virtually all cultural influences that impact growth - temperature is definitely one of those influences that can be most limiting ....... until it's no longer the most limiting and something else is. We have a member that feels more light is the answer to all plant ills, but a quick review of Liebig's Law illustrates that improving light levels can only make a difference when light is the most limiting factor. If a plant is fresh out of water or nitrogen, more light can't improve its lot. During June/July/Aug most plant growth comes to a grinding halt and chlorosis/partial defoliation is common for many plant species. A defense mechanism against drought. Even the toughest plants (e.g. Bougainvilleas) grow very slowly, putting out puny leaves. To put things in perspective, during the summer months, temperatures hover around the 100-110 degrees ALL DAY LONG, with relative humidity of 10-15%. So wouldn't you agree that having to grow our plants in hell for 3 months of the year is more of a limiting factor than a less than ideal aeration/drainage? I can say with a great deal of certainty that the less ideal aeration and drainage, the more intense are the limitations imposed by hell. Any "ideal" cultural factor is better than a compromise. Poor drainage and aeration limits a plant's ability to take up water (and nutrients), which magnifies the limitations imposed by heat and perhaps light loads beyond photosaturation.

Whew! I feel like I just took a test, but you did make me think. ;-)

Al

I am copying and posting ewwmayo's question from the older thread/same title - I think it is very good question, follows question by other member about proper way to water - and posting on newer thread with (so far) less comments, maybe will be read by more ppl:

ewwmayo(ON-CA 6a)

Al
- Any thought on soaking pots to flush accumulation of salts vs. the
watering/waiting/flushing method? Keeping effluent separate is obviously
difficult to limit in the former, but it is quite time-saving when
growing smaller plants indoors.

I've been trying to reconcile if the higher amount of water allows
for more undesirable salts to dissolve, which then reaches equilibrium
and drain away (for the most part).

My plan is to continue testing and learning more on this particular topic, although maybe you already have a good answer.

So far I think I've managed a decent mix and good light, but managing
nutrients is something I need to learn a lot more about still!

I hope it is OK to do this; it is good to read either of the threads since there are good and sometimes different questions asked on different threads...I know I miss some good posts occasionally.

Question originally posted -here-...

Rina

Al, first of all thanks a lot for the detailed quick response! Now, i'm afraid i still have more questions which i hope you'd still be patient enough to answer.

Let me first summarize the challenges of container gardening as I understand them so far:

1- Different fluid mechanics due to detachment from the (practically infinite) earth. This makes PWT the MAJOR drawback, but until i read your comment, i thought it was the ONLY one as far as fluid mechanics were concerned.

2- Small pot volume (the challenges here include, besides root congestion, very limited ability to soften the blow, if you will, of sudden moisture/temperature/pH level changes).

Based on these two main factors (small volume+fluid mechanics), the soil particle size becomes far more important in pots, than it is in the ground. Finer particles means adversely affecting the fluid mechanics even further, including an even higher PWT level. Moreover, finer particles, in a limited volume, translates to an even greater compaction (with its associated aeration/drainage problems). Also, higher density in a limited volume means even more vulnerability to temperature changes, etc.

So it's no wonder you pay a lot of attention to the particle size of the pot's soil. HOWEVER, here is where i get confused. You seem to discourage the use of organic ammendments because they eventuallly decompose into the fine particles we're so wary of. Ok, that's an excellent point, BUT then why would many sites/people promote organic ammendments, partly for their (eventual) ability to clump finer particles togeather into coarser ones? Is that a myth (or a mere unsubstantiated ideology as you seem to hint)? What about prescribing organics to de-compact (ground) caly soil? Also a myth?

You said you sometimes use ammendments for the *ground*, but very infrequently. May I ask why do you use them, albeit so scarcely?

You additionally disagree with the claim that synthetic fertilizers erode the soil and you offered posting a link to a comparison between organic and synthetic fertilizers, yes please i'm very much interested in reading it all :)

Finally you wrote:

"To a trained eye, the effects of root congestion can immediately be seen by noting the distance between leaf bundle scars on some plants. Often, it's apparent how many times a plant has been repotted, and when (the year) it was repotted can often be seen in clues the plant wears as evidence".

I would very much appreciate it if you could provide links (with pictures) that might teach me how to read these signs myself!!

Many Thanks!

--The Accidental Gardener

I will take a stab at the question posed by ewwmayo while Al gets a chance to answer. The problem at hand is: Soaking pots in water vs. top watering to flush out the salts.

So just thinking out loud:

Soaking reaches every part of the pot more easily and thus has the ability to dissolve more of the salts. So soaking it for say 10 minutes and then lifting the pot out drain the excess results in water movement downwards that should simulate the flow effect drawing air in and dissolving/dislodging more salts out of the pot. Doing it a second time can make it lot more effective - may be a bit of an overdo on a regular basis.

Top watering will for a short period saturate completely but if it is the gritty mix then it will lose that water pretty quickly. I do not know the how much air space is left in a saturated mix. Perhaps around 20-25%. I need to do a search on that. So for the 10 min of soaking we can lose that much of water that could dissolve more salts. In the end though, the difference could be minor.

I use both the methods depending on what is convenient at the time. When I think there is salt stress, I opt for dunking, draining and repeat it several times with fresh water.

I thought I will add these are the points I am basing my observations:

a. Total solubility of a volume of water is constant at a certain temperature.

b. Flowing/turbulent water will dissolve quicker, stagnant water will take longer.

Something I did not consider in my last post but for comparison between the two situations it does not matter.

c. Solubility decreases with amount of TDS already present in water.

d. Solubility increases with temperature.

e. Resistance of the ingredients to let go of its salts.

f. Acidity of water (if any) as it will help remove salts by chemical reaction.

There you go I feel happier.

Al , since the subject of synthetic fertilizer was brought up,I can't seem to remember something and I am hoping you can stir up my memory...

Plants do not need to have beneficial microbes in the soil to perform well, correct?

Many around here are into injecting them with very expensive fluids, one called Jungle Juice a whopping 60 dollars for a quart that claim to give plants in pots all they need to absorb nutrients better...They even sell fertilizers with added beneficial microbes...

Then there people who refuse to buy synthetic fertilizers saying they kill what ever beneficial biota or microbes that do exist in their containers? What gives?

What are your thoughts? Do you have a link I can go to that will reactivate my memory?

Thanks so much Al..

Mike

Thanks for bringing that post I missed to my attention, Rina. I'm glad SOMEONE is focused. ;-)

Al - Any thought on soaking pots to flush accumulation of salts vs. the watering/waiting/flushing method? Keeping effluent separate is obviously difficult to limit in the former, but it is quite time-saving when growing smaller plants indoors.

I've been trying to reconcile if the higher amount of water allows for more undesirable salts to dissolve, which then reaches equilibrium and drain away (for the most part).

My plan is to continue testing and learning more on this particular topic, although maybe you already have a good answer.

So far I think I've managed a decent mix and good light, but managing nutrients is something I need to learn a lot more about still! Either practice is far superior to simply watering in sips, which ensures not only a build-up of dissolved solids (salts) that inhibits water/nutrient uptake, but also ensures skewed nutrient ratios. The severity and speed with which nutrient ratios become skewed varies with how divergent the nutrient ratio supplied is from the nutrient ratio used. E.g., ratios would become skewed more severely and much faster when using a fertilizer like 10-15-10 than when using a fertilizer that more closely matches that at which the plant actually uses the nutrients, like 9-3-6, 24-8-16, or 12-4-8 - all 3:1:2 RATIOS.

I prefer to flush soils from above rather than immerse/flood and drain. If there is only 1 or 2 pots and the volume of water used for immersion is substantial, there isn't much to set one method apart from the other as substantially superior, but the more pots you immerse/flush in the same dilutant, the more the 'flush from above' method stands apart as superior.

Faisal said: Let me first summarize the challenges of container gardening as I understand them so far:

1- Different fluid mechanics due to detachment from the (practically infinite) earth. This makes PWT the MAJOR drawback, but until i read your comment, i thought it was the ONLY one as far as fluid mechanics were concerned. At any given time, there is a long list of cultural influences that have the potential to be THE most limiting factor; and sometimes it's the residual results of exposure to a critical factor that remain the most limiting factor. Examples - after surviving an extended period of a severe nutrient deficiency, even after correction, the aftermath of that limitation may remain for a period of time as the factor most limiting to growth and vitality. A sever N deficiency could cause most leaves to be shed. Once the deficiency is corrected, it may be the lack of foliage that most limits the plant. Very frequently, a soggy soil is the most limiting factor. Even after the soil is allowed to dry down to the point it offers the plant the best conditions it can offer, the damage caused to roots might still be what most limits the plant.

Considering only fluid mechanics/hydrology, too wet or too dry would be the factors most likely to be limiting. Too dry is a problem of equal severity in any medium, but the likelihood and severity of 'too wet' is highly variable; so much so that in some media it is virtually always an issue, and in some other media it is virtually never an issue.

2- Small pot volume (the challenges here include, besides root congestion, very limited ability to soften the blow, if you will, of sudden moisture/temperature/pH level changes).

Based on these two main factors (small volume+fluid mechanics), the soil particle size becomes far more important in pots, than it is in the ground. Finer particles means adversely affecting the fluid mechanics even further, including an even higher PWT level. Moreover, finer particles, in a limited volume, translates to an even greater compaction (with its associated aeration/drainage problems). Also, higher density in a limited volume means even more vulnerability to temperature changes, etc. True - nothing here that I would not agree with or that I would feel the need to qualify for accuracy.

So it's no wonder you pay a lot of attention to the particle size of the pot's soil. HOWEVER, here is where i get confused. You seem to discourage the use of organic ammendments because they eventuallly decompose into the fine particles we're so wary of. Ok, that's an excellent point, BUT then why would many sites/people promote organic ammendments, partly for their (eventual) ability to clump finer particles togeather into coarser ones? Is that a myth (or a mere unsubstantiated ideology as you seem to hint)? What about prescribing organics to de-compact (ground) caly soil? Also a myth? I couldn't agree or disagree until you decide whether we're talking about container culture or growing in the earth. What you said in the immediately previous paragraph would all be true if we're talkings about gardening/growing in the earth. I try not to discourage using organic soil amendments (organic fertilizers) as a way to provide nutrients when someone is bound to that method by their ideology. However, if we're discussing how to best maintain control of and efficiency in the method we use to supply nutrients, it's going to be very difficult to make a case for doing that organically. As organic soil amendments (feather/horn/blood/cottonseed ...... meals, compost, dead leaves, and other ingredients that break down fast enough to be viable sources of nutrients, they impact the physical structure of the medium. To me, it doesn't make sense to sacrifice the mediums structure so we can say we're feeding the soilo when everything provided by the collapsing soil can be found in a bottle of Foliage-Pro 9-3-6 or equal. It's much easier to provide plants with the best opportunity to realize their potential if we focus on providing them with a medium we can rely on to retain its structure for the planned interval between repots, and take total responsibility for providing all the essential nutrients via out supplementation program. We can be sure this works because a poor or collapsing medium ensures nutritional problems, while a healthy medium and a sound nutritional program offers the best chance at good root/plant vitality, all else equal.

You said you sometimes use ammendments for the *ground*, but very infrequently. May I ask why do you use them, albeit so scarcely? I think you misunderstood. What I said was, "In keeping with the thought I like easiest and best, I adhere pretty tightly to making sure my soils in beds and gardens are doing the feeding. I supplement VERY infrequently in open ground - not bound by ideologies." When I said "I adhere pretty tightly to making sure my soils in beds and gardens are doing the feeding" , I meant I use organic matter to ensure a healthy soil and a microbiotic environment populous enough to ensure the nutrients from that OM are there and available for uptake. "I supplement VERY infrequently in open ground - not bound by ideologies" means that I don't supplement with FERTILIZERS in beds and gardens, other than rarely and for specific plants. For example, the only chemical fertilizer I applied this year in my beds/gardens was an application of Sprint 138, an Fe chelate. I planted a cutting I started from a witches broom I found growing on a bald cypress on a vacant property. It tends toward severe chlorosis for some reason, which I diagnosed as an Fe deficiency. The Fe chelate took care of the chlorosis completely, so my next move is going to be a S application to lower pH and make more Fe available.

I might not have expressed it appropriately, but my intent was to impress the point that I rel.y on primarily organic means of supplying nutrition in open ground, which goes a long way toward showing my focus is driven by results as opposed to ideology.

Continued below ................................

You additionally disagree with the claim that synthetic fertilizers erode the soil and you offered posting a link to a comparison between organic and synthetic fertilizers, yes please i'm very much interested in reading it all :)

In my gardens and beds, I adhere pretty strictly to the idea that on an ongoing basis you should use organic products/soil amendments that build the soil structure to minimize the need for soluble (read synthetic) fertilizers and nutrient supplements. That said, there are times you NEED individual nutrients to complete the assortment of essential nutrients plants take from the soil. If you're limited by a rigid 'no chemical' ideology, you either deal with the abnormal and sub-par growth or wait, while you hope adding more organic matter eventually solves all the issues. If you are NOT limited by rigid ideology, the issue is easily solved with a soil test and the addition of the appropriate nutrient(s) via a chemical compound like potash, various nitrates, phosphates, etc.

There are extremists at both ends of the organic vs. chemical approach to gardening. Some never think about the soil, believing it ok to keep adding chemicals to ‘hopefully’ produce growth. Others would never THINK of using a chemical and will chastise anyone who does. When it comes to my gardens and beds, I'm in the middle, but as noted I do lean quite heavily toward the organic side, though I stop short of telling anyone what they must do to be a good gardener. ;o)

Where container culture is the topic, soluble synthetic fertilizers get the nod from me - hands down. They are easier to use; we know exactly what nutrients your plants are getting and when they are getting them; delivery of nutrients does not depend on the activity of soil organisms whose populations vary in boom/bust cycles in containers; you're using a soluble product, not an organic soil amendment that has the potential to clog valuable macro-pores; you needn’t worry about soil structure, because if you’re smart you’ll have built it into the medium before you planted in it ….. but let’s save the container soil topic for another day.

I mentioned there are those at one end of the spectrum who would never lift a finger to improve their soil. Adding organic matter to their soils would be as foreign to them as adding exercise to their life’s itinerary. On the other end, are those who stand ululating and hand-flapping (credit to Dan for that one) at the very thought of anyone using Miracle-Gro. From the plant’s perspective, both extreme positions are ridiculous, and from my perspective, both extremes are unnecessarily self-limiting. The plant just wants to grow to it’s genetic potential. To do that, it needs a full compliment of the nutrients plants take from the soil, and it doesn’t care if they come from compost or Miracle-Gro.


Perhaps a more logical approach to plant nutrition might be to look at soluble synthetic fertilizers in the same way we look at IPM practices. Use the most naturally harmonious method/product we can to bring plant growth or yields into the acceptable range. I realize that in most cases, we can do this by adding more OM, but not always. Often too, time is a consideration. We may have someone who wants to plant immediately, in soil that is deficient in one or more nutrients. We probably shouldn't expect someone to forgo their own freedom of choice and wait two years or more while the soil is fortified/improved only via the addition of organic matter.

There is a technical difference between a fertilizer and a soil amendment, but even that point eventually becomes moot from a strictly nutritional perspective. Plants take up elements that are dissolved in the soil solution and in ionic form. What they take up are salts. The large molecules that make up hydrocarbon chains in organic fertilizers/soil amendments cannot be taken up by the plant unless the hydrocarbon chains are broken down into elemental/soluble form by soil organisms. At that point, the elements from soluble fertilizers are the same as the elements from organic sources, which is why the plant could care less. At the point in time where nutrients are assimilated, they are ALL soluble and in elemental form, regardless if they came from a dead fish, compost or a hose-end sprayer.

If we could only achieve happy healthy plants in a soil teaming with life, using only organic soil amendments and fertilizers, how do we explain hydroponics? ... no medium, or an entirely inorganic one, and only soluble sources of nutrients. At the very least it suggests there is a middle ground in which everyone can seek their comfort level. I’ve been growing perfectly healthy plants in containers in a medium whose only organic fraction is 1/3 or less pine or fir bark; the rest of the ingredients are large mineral particles like Turface and crushed granite. I’ve used ONLY soluble fertilizers in these soils, with the hundreds of pictures I’ve posted here at GW serving as concrete proof that happy, healthy plants can indeed be grown using only synthetic soluble fertilizers if the soil structure is favorable …… which leads me to the reason for writing this:

Colloquially, the term 'organic' formerly applied to things once living, but even some plastics contain carbon and are considered organic compounds as well. It really is misleading when we throw the word around w/o much consideration, but I admit to being guilty of it from time to time as well. Technically, urea, ureaformaldehyde, isobutylidene diurea, and crotonylidene diurea (forgive me if the spelling is slightly off) are all organic molecules, and actually do an extremely good job of feeding microbes, which reinforces the idea that synthetic fertilizers are getting framed for the microbial murder rap that should be hung on the effects of reduced OM in the soils. The microbial murder rap should be hung on the effects of reduced OM in the soils; purposely redundant so it couldn’t be missed.

It's a vicious circle; mineral soils can support optimal plant growth (nutritionally speaking) only if enough young decaying matter is returned to the soil regularly and frequently. Prairies and forests are virtually self sustaining because all vegetative matter is recycled back into the soil. If we regularly mow and bale the grassland, or log off the forest, nutritional deficiencies are assured as a result of our removal of the OM that would have provided future nutrition - thus the tendency/need for us to adhere to the practice of replacing the lost nutrients with chemicals.

In our gardens/beds/lawns ..., we can add compost or other OM to replace the vegetative matter we remove and use or discard. For more than 20 years, I've used compost regularly in the gardens/beds, and apply fine pine bark mulch 2-3" thick, usually every other year. I have extremely healthy soil and rarely find it necessary to use anything synthetic.

You can find opinions all over the net that chemical fertilizers are laying waste to the landscape, and wiping out microbial populations faster than chocolate disappears from the candy dish in the family room. Are these opinions based on political views and a radical ideology, or warranted and based in fact?

In research by Texas A&M University, intensely managed (read ‘managed using chemical fertilizers‘) sports fields with mostly a sand substrate showed no shortage of soil life. That is there were 10s of millions of bacteria, and 10s to 100s of thousands of fungi per cubic centimeter present in the heavily managed soils. Part of the study included measuring soil life in 11 inches (deep) of pure sand, with no organic amendments whatsoever, over which washed sod was placed. As the sod 'grew in', soil life populations increased almost immediately, 10-100 times .

Soil life populations just sort of hang loose, waiting for something they can digest. If they don't get it, they die and feed off each other. When organic matter is introduced into the soil, they break it down, and their numbers increase. When they've consumed the organic matter, they die and consume each other, but the base population remains, ready to spring into action the moment more organic matter becomes available.

What do fertilizers do? They make plants grow. Sure, extremely high concentrations of chemical fertilizer poured on the soil in volume might kill some microbes in the immediate area, but the o/a affect of chemical fertilizers is actually an increase in microbial populations through increased plant growth. You need only look to the fact that the rhizosphere (root zone) of plants is such a popular gathering place for soil biota to see increased plant mass promotes a marked increase in soil life. It's actually the continual 'taking' of OM from gardens, agricultural fields, lawns ... w/o replacing it that reduces or inhibits the communal activity of microbial populations. Even then, they're virtually never in short supply and are ever ready to bounce back ... if you just give them something to eat.

None of this addresses the hot button political, ideological issues too many wish to export from their own value set, other than the fact it points out the folly in occupying the margin’s extremes. Again, I'm pretty pragmatic and results oriented, so I tend to approach this subject from a plant/soil perspective and leave the politics to the ideologues. My personal view is that in the o/a picture, a chemical fertilizer or nutrient supplement judiciously and responsibly applied to our gardens when it's found to be needed isn't the earth's end; and I prefer to use my own sense of right/wrong to set my course, rather than be told what I need to do to be a good, responsible student of husbandry.

That said, avoidance of unnecessary chemicals in the gardens/beds to the greatest degree I feel is reasonable, is still my normal MO. YMMV, but options are good, and I prefer to keep them open.

Finally you wrote:

"To a trained eye, the effects of root congestion can immediately be seen by noting the distance between leaf bundle scars on some plants. Often, it's apparent how many times a plant has been repotted, and when (the year) it was repotted can often be seen in clues the plant wears as evidence".

That someone can read a plant's history comes from being intimately close to plants for a long time and closely observing their reactions to the effects of increasingly more severe root congestion and their reaction after the effects of root congestion have been eliminated via root pruning. To try to explain it entirely would take a long time, but even though I won't be using leaf bundle scars in this case, this Madagascar palm tells a clear story about root congestion:

Al

Wow! thanks Al for the wealth of information, that was really a lot of help.

At this point i guess i have one final question, regarding repotting, but first a little introduction is in order.

In my (25+ gallon) containers i grow mostly vines (all tropical beauties) that are attached to the walls outside the house. The problem with repotting vines every couple of years is that i'd have to first hack 'em up off their wall support after i have impatiently waited for them to reach the desired size (a height of 8 feet; width/span of 5 feet)... you can only imagine the extent of emotional pain a move like that would cause me.. so my question is:

What if I keep my vines untouched, and just remove half to two thirds of the soil surrounding the main stem in the pot? I mean i coud keep a radius of say 4-5 inches around the main stem, and replace all soil outside that range. Would that work?

faisal.

Faisal, where are you growing these vines? Where do you live, what zone?

I live in Florida where the soil is pure sand. I work to amend the soil as best I can to contain moisture and nutrients. I'm not sure about the Texas study, but my results using compost and wood chips have brought beneficials into the garden bed. I have lots of worms which didn't live here prior to amending. Another problem in Florida are Nematodes. They dislike organic matter and I'm able to grow plants that are not resistant to them.

The compost, manure and wood chips also help keep the hot sun from drying the soil. I am able to grow plants I could not grow previously.

Are your pots growing on the ground? Could the roots escape the bottom of the pots into the soil?

I have a few vines growing in pots. I also have quite a few trees. Some have broken out of the pots and rooted into the ground. I decided to leave them alone and let them grow. They are beautiful, growing up a wood fence and I would hate to pull them off.

Please provide more growing information. It would help.

Jane

Hello Jane,

I live in Riyadh, Saudi Arabia. I guess it would be the same zone of Death Valley, California (very dry most of the year; a raging inferno during the summer).

I grow my plants in pots placed over porcelain tiles outside the house. Here's a picture of one side of the yard:

and another one:

These plants looked all but dead this summer, but they perked right up come fall.

All houses in Saudi are walled in. In other words, there must be walls between you and your neighbors, you and the street (in saudi, the absence of such walls would be an open invitation to trespass, besides, it's city code).

It can be a bit suffocating when you're out sitting in the yard, staring at bare walls. And because of the small area of the yard, I cannot dig up some of these tiles to reach ground (pipes/electric cables/city water resevoir/sewage, all underneath these tiles) So i thought having something green grow over these walls would greaty alleviate the sensation of being caged in.

faisal.

Faisal, I can feel your pain. For many years we used to live in a house similar to yours in Delhi. I am just throwing out a suggestion. How about a wooden box for a pot? Then when it is time to change the soil, you can unscrew all around and expose the entire root ball. Probably build a bigger box is needed and repot it.

Faisal

I think the enclosures and the tiles add to overall heat - but that's the conditions you have...Have you considered using bigger containers? - I am thinking longer (not necessary wider) and perhaps deeper containers, perhaps custom built from wood.

I wouldn't use manure and wood chips in containers (bark yes, chips no) - JMO.

Rina

edit: I see that I am thinking similar as tropic :)

Some of the advice above is good, but some is a hodge podge of what might work if growing in open ground mixed with appropriate container practices, but please DO avoid wood chips and manure in containers. There are multiple issues associated with either practice in container culture. Pine bark is a good choice as a container media base, and in some cases I think melaleuca (native Australia) bark can be used after processing - if that tree grows in your country.

What if I keep my vines untouched, and just remove half to two thirds of the soil surrounding the main stem in the pot? I mean i coud keep a radius of say 4-5 inches around the main stem, and replace all soil outside that range. Would that work? You would essentially be somewhere between repotting and potting up, so it wouldn't be as effective as repotting, but it would be better than potting up. It's a compromise that would allow you to enjoy your vines much longer than you normally would be able to if you were undertaking a full repot on a regular basis. I think how stiff/flexible the vines remain is going to be a major consideration. It would be very reasonable to pot up every year or every other year until such time as the vines' lack of flexibility prohibits that practice, then cut back hard and repot - sort of like pressing the 'reset' button.

Al

thanks a lot Al, Rina and Tropic for all the great advice and suggestions.. (especially you Al, you have been amazingly generous!)

faisal.

Best luck, Faisal. I'm glad to have made your acquaintance. Your kind words are appreciated.

Al

Dare I hope that you are still active in these forums, Al? I will admit that I have skimmed many of the posts you have made and even with that have found a great deal of wonderful information that seems completely absent from the books, magazines, and websites from which I have previously gathered my information. I "got into" container gardening and houseplants only about a year ago. In one of your posts you mentioned how container plants could start at a 9 out of 10 in their health/vitality, and good repotting could keep them close to that for their entire (long) lifetimes. before finding your wise posts, I had already begun potting-up all my house plants that have been with me for about a year (previously left in their original containers). Now I regret that.

Due to my regret, I wonder if, since it is only mid-spring, if I might be safe in repotting my just-potted-up plants, or if I should wait and try that next year? Some have been potted up in good soil...but their old soil was mainly left intact, some I believe I have potted up in soil that is too water-retentive, and those too had their original root-ball and soil left in-tact. (And this causes me to rethink my plans for topdressing the very large outdoor containers I have too...ought I to repot there as well?)

I wonder if you could point me to a good visual resource for the root-pruning you describe. Normally I prefer to absorb my information via words, but I cannot picture what you describe as problematic roots.

Al, just to let you know I'm thinking of you and always grateful for all that you have shown me through the years. Still around helping others with all you have shown me on other forums, but still reading much of your offerings..Thanks again and hope all is well.

Mike