Gardening science versus tradition

Discussion in 'Plants: Science and Cultivation' started by Margot, Jul 26, 2020.

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  1. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    • 'Apples': "The drainage studies are disproving the effectiveness of a layer used in improving drainage (from the soil layer) within the container".
    • 'Oranges': "you're advocating its use as a capillary break to prevent a plant from drowning in a pool of excess water that has already drained".
    These are clearly two different applications. In the 'Apples' scenario the perched water table is constant, with its size unchanged by the introduction of a rock layer so there is no extra water drained from the soil layer. Conclusion: The rock layer serves no useful purpose in this application.

    With the 'Oranges' scenario, I acknowledged the use of the layer as a capillary break to be valid and that it has its uses by saying, "As you pointed out, a capillary break has its uses in certain situations but in most cases it would be simpler just to make a practice of emptying the saucer." Yet you ended up repeating yourself in citing an example which you provided earlier. I do not disagree with either the layer's application as a capillary break or with the example given. You haven't added anything new to the discussion. Furthermore, by acknowledging the valid use of a capillary break in certain circumstances, are you not also tacitly agreeing that it does not need be installed in ALL cases? Are we then not in fact in agreement on this particular application?

    One can easily see the amount of water in a pebble tray by sloping the layer on the edge bordering the tray. Alternatively, an open-ended cylinder can be inserted vertically into the layer so that the water level can be seen. Once again, there is no need to install the capillary break inside the container.

    I acknowledged that point by saying, "In order to not reduce the amount of usable soil, the original volume of such has to be maintained and in doing so necessitates the use of a taller container than otherwise required." Yet you launched into a long diatribe on scientific methods. Please tell me how you would introduce a new layer of material, while keeping the existing soil without the use of a larger container.


    In the playing field scenario, the capillary break allows water to drain into the tile layer while preventing water from wicking back up. But with a container, there is no need for such a layer as long as the saucer is emptied of its contents. There is nothing new here as this is the same as the 'Oranges' scenario.
     
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  2. Sulev

    Sulev Active Member

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    Another strawman?
    Could you provide any proof?
     
  3. Sulev

    Sulev Active Member

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    Isn't just much easier to add drainage to the bottom of the container, than shaping pebbles into certain form or installing some cylinders?
    I repeat once again: the drainage layer is not obligatory. It may help in certain cases (contrary to the myth buster's claim, that drainage layer is always not only useless, but even detrimental, with no exeption).

    I think, I did show you verbally and graphically need for larger/taller container, if you add something rather voluminous, like another layer into container, a year ago. I will not argue with my former claims. Please stop setting up strawmens! They are irrelevant to the topic!

    Yeah, as long... But these "myths" are mostly addressing the situation, where the saucer is not emptied so carefully. Why a scientist addresses her myth busting so wrong?
    I can't prove you what these "myths" told about for what conditions they recommended the drainage layer, as those myth busting sites are overwhelming now and I can't find sites where the drainage layer was recommended, when running the Google search. They were still present last year. There was even a site that compared cases: tray pebbles vs drainage layer inside the container. But it seems, that mythbusters and their disciples have attacked those sites, so they have removed their content.
    According to my memories, there were following cases, where those "myths" recommended to use a drainage layer:
    1. Large containers (if you have a container with a 1 metre depth, then adding 5 cm of drainage layer to the bottom of it won't affect the perched water table critically, compared when adding that to the container with 15 cm of depth), where emptying the plant saucer is troublesome/not so easy task.
    2. Containers with no drainage holes at all (use of such containers is usually not recommended at all).
    3. Cases where plant owner is not so skilled/careful to provide optimal watering regime, often as a recommendation for plant owner, who has already caused some damage to his/her plants because of water logging (usually for house plants that have rather large containers, but don't tolerate water logging at all, such as figs, citruses, bananas etc).

    Of course, there were sites, that promoted drainage layer without specifying conditions, when to use this layer, or declared something very general, like "add drainage layer, when drainage is inadequate".
     
    Last edited: Aug 4, 2020
  4. Sulev

    Sulev Active Member

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    With some effort to find any sites, that promote adding a drainage layer into containers, I found this:
    Container & Planter Gardening in Calgary

    Another one:
    Using 100% Fine Perlite in Israel---The Schundler Company
    Did these myth busters ever test drainage layer in large containers?
     
    Last edited: Aug 4, 2020
  5. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    I'm merely laying out the two scenarios or different intended uses of the layer that are up for discussion.
    • What do you consider to be a straw man here? State your concern and please be specific.
    • I haven't made any assertions. What needs to be proved?
     
  6. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    Let's see. To create the slope pour the rocks into the tray but not right up to the top edge. Similarly, stand a piece of piping on the tray before filling it with rocks. Do you consider either of these methods to be a lot of trouble? Having the capillary break external to the container has the benefit of not having to use a container that is larger and heavier because of the rocks.

    The issue of removing water after it has drained from the soil layer is outside the scope of the studies. In any case it is poor practice to intentionally allow a container to sit in a saucer of water, bog plants and such aside. Why go through the trouble of creating a solution for a problem that can be simply avoided in the first place? Of course there are exceptions, as you've pointed out many times.
     
  7. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    The websites you cited are in the business of selling products and not that of conducting research or education. The information contained within should be taken with a certain degree of skepticism.
     
  8. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    I decided to review the drainage discussion so far. This is what I found.

    You referenced a post you had made in the past in which:
    The diagram in the post supports your statement. The first three containers illustrate the effect of adding a layer of material. The third container is the starting point. The second container is the result after adding a layer. The first container shows that in order to not decrease the volume of usable soil, a taller container is required. Note that the perched water table remains constant in all three containers. This is your conclusion. This is the same conclusion presented in these (previously referenced) articles:
    In this scenario, 'Apples', the question is whether a rock layer below the soil results in additional drainage of water from soil layer. The answer is 'No, there is no improvement in drainage'. Therefore, are you not in fact in agreement with their findings on this point? The findings apply to all containers, with or without a saucer, though there are other considerations with those that have a saucer in regard to the water that may drain into it.

    In the same post you said:
    You are advocating the use of a layer to function The layer, in the manner as presented by you, functions as a capillary break to prevent water from wicking back up into the container. The first two containers in the second row are used to demonstrate this. This second scenario, 'Oranges', deals with mitigating a potential problem of a container with a saucer.
    I agree. "It may help in certain cases" implies that it doesn't help in the majority of cases, certainly so if growers follow good practice of discarding excess water from the saucer. Growers should be encouraged to follow best practices for obvious reasons.


    In summary, it seems to me we are in agreement on both these separate scenarios. The studies in the two articles deal with the first scenario. The use of a similar rock layer functioning as a capillary break is not mentioned as it is outside the scope of their research. Your arguments are directed towards the second scenario. Therefore have you in fact not set up a straw man argument, based on your selective interpretation of the results, to attack the validity of the studies' findings?
     
    Last edited: Aug 6, 2020
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  9. Sulev

    Sulev Active Member

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    Please, prove your claim "the question is whether a rock layer below the soil results in additional drainage of water from soil layer. The answer is 'No' "

    First. I haven't seen any "myths" claiming additional drainage from the soil level. These "myths" usually claim improved drainage of the container.

    If the "science" by these myth busters was a proper science, then the characterization section of their papers would describe in detail, what these "myths" actually claimed, with quotes and sources. But myth busters did not even bother to describe in detail the "myth" they fight.

    Second. I am not advocating the use of a layer to function specifically as a capillary break to prevent water from wicking back up into the container. I am pointing a case, where drainage layer could be useful. Please note, that in case the container sits deep in the excess water pond on the plant saucer, then part of the excess water remains in the soil (it has never drained out of the container, on the contrary of your claims, no need to wick it back into the soil). The part of the soil, that sits in the excess water, has worse conditions for roots than in the perched water table ever, because in the "pond" almost every pore of the soil fills with water (only some air bubbles can remain in the soil, but even these will solve in the water, if that stays for long time), but in the perched water table larger pores are containing the air (the water stays in the perched water table using capillary forces, pores larger than capillars, drain partly empty). Plus air bubbles in the perched water table area are not so willingly solved into the water (the water pressure is lower and even if the bubble would fill with the water, then the water comes from the perched water table only and some other part of it fills with the air). Plus in case the soil sits in the excess water pond, then almost all the water, that is drained out of the container, can be wicked back to the soil, and there could be much larger amount of water in the "pond" than contained in the perched water table. So these wet conditions in the lowest part of the soil can last much longer than in case the drainage layer is present and the soil is separated from the excess water "pond". Therefore I depicted these cases on my old diagram with a red color.

    Plant owner can adjust the height of the perched water table in containers (how much space there is for roots above it) by selecting coarseness and organic content of the potting mix, volume of the mix and the size and shape of the container. Presence of a drainage layer has no significant effect on the height of the perched water table, but it may significantly help to shorten the time, when the perched water table stays at its maximum height. That could be a big releaf for plants, that don't tolerate water logging around the roots.

    I don't compare apples vs oranges. These mythbusters claim, that a drainage layer would not improve drainage, and even makes situation worse (they don't even hint on possible exeptions). I don't compare scenarios, I just point out the most obvious cases, where the positive effect from the drainage layer could appear. If a scientist wants to prove absence of the positive effect, then she should have been tested these cases. And I point out some other mistakes these myth busters have done, if their work pretends to be a science (like blaming one factor on adverse effect, caused by change in completely another factor, etc).

    I don't know, what cases are minority and what cases are majority. I haven't conducted any research, how many plant growers are using plant saucers or other excess water collectors for their house plants, and how many of these have ever been left filled with excess water after watering. If this myth busting was a proper science, then it would state, if their conclusions are effective for minority or for majority of cases, if exeptions exist, or would point these exact condition, where their conclusions are valid, if they only tested certain conditions and don't have an idea about the other conditions.
     
    Last edited: Aug 6, 2020
  10. Margot

    Margot Contributor

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    Please. Sulev. Give it a rest!!!
     
  11. Sulev

    Sulev Active Member

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    Hi, Margot!
    It is nice to hear from you!
    How are you?
    Could you please explain, why did you remove your 'like' from Tom Hulse's posting? I was positively surpriced that we had finally something common - we both liked that posting, until you removed your 'like'.
     
  12. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    Perhaps not the best choice of words on my part so I have modified the wording.
     
  13. Sulev

    Sulev Active Member

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    Now that is even farther from the truth, because, as I wrote earlier, I don't use a drainage layer in my containers.
     
  14. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    You're nit-picking. I have further changed the wording to accomodate.
     
  15. Sulev

    Sulev Active Member

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    Whatever. I will not reread these old modified postings any more. I usually fix only some typing errors and grammatical mistakes in my messages, if I find any (I know I am generating lots of typos, especially when writing from my mobile phone), so much time after posting. Changing the point of a message after it has already answered by the opponent does not sound reasonable.
     
  16. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    There is a big difference between changing the wording to clarify the thought being conveyed and that of altering the direction of thought. Please note I struck out my original words rather than deleting them. There is no attempt to hide from the reader what was there previously.
     
  17. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

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    I'm starting to agree with Nik, that we should close this, as I don't think there is anything being gained here. @Sulev and @Junglekeeper, any objection? You are the two main players here.
     
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  18. Junglekeeper

    Junglekeeper Esteemed Contributor 10 Years

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    No objection at all. There's nothing to be gained by further discussion. It was my intent to stop anyway as my thoughts on the matter have been presented. I'll leave it up to the readers to decide for themselves.
     
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  19. Sulev

    Sulev Active Member

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    For me, this topic is practically exhausted. I would no longer intervene here unless I was approached directly or new arguments of dubious value were put forward to force me to argue. It is up to you, if you like to close the thread or not. I am not aware, what objectives should or should not be gained for keeping threads unlocked in this forum.
     
  20. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

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    OK, closing. As soon as I figure out how. :) I think I have it.
     
  21. Daniel Mosquin

    Daniel Mosquin Esteemed Contributor UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    One of the disadvantages of being the forum admin is seeing conversations like this erupt when I'm away, but one of the advantages is I get to be the final word.

    Just a reminder about the Forum Charter: Forum Charter , specifically "Imagine you are a guest seated at a table for a dinner party of infinite potential size. Certain courtesies and formalities exist because all guests are (initially) equally welcome to join the conversation until their behaviour suggests otherwise: be courteous of others; be respectful in your disagreements; be gracious; be engaging and encouraging of others to join the conversation; and be charitable."

    Being courteous to others extends to people who are being discussed, not just those in the immediate conversation.

    As to the scientific method, my personal take is that it is difficult to apply in complex, multivariate situations, in agreement with this: Scientific method - Wikipedia .
     
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