Natural Plant Growth Inhibitors.

Discussion in 'Planted Tank Equipment' started by Greystoke, Oct 31, 2013.

  1. Greystoke
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    Greystoke Specialist

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    Some of these compounds come from decaying/rotting plant materiel and excess fish food, such as: flakes.

    They are difficult to detect as they are produced in very small quantities, but – even at these levels – they are still potent enough to affect plant growth.

    Since you can’t detect them, or remove them yourself, they are – fortunately - broken down by bacteria, which turn them into in-organic solubles that plants can use as nutrients.

    In other words: Our plants grow at the behest of bacteria that consume inhibitors.

    Question: What happens if you don’t have enough of these bacteria?
    Answer: Your plants won’t grow as fast as they should, or sometimes . . . not at all.

    Case in point:
    This is what my tank looked like recently (3 Sept 2013):

    [​IMG]
    Notice that big piece of driftwood and also the “cobbled” substrate.

    The plants pinned to the drift wood – like Java fern & Anubias – wouldn’t grow an inch over a period of three months.
    By comparison: the Vallisneria – on the left, which are planted in a container - grew normally.

    So what caused this? I checked every potential cause that I could think of, including the last idea from Ray, who suggested that the parsley culture in my sump enjoys the full sun for a few hours a day, including all the CO[sub]2[/sub] in the air it can get. That means that it has a distinct advantage over the immersed plants in the tank, which it should out-compete for nutrients.
    [​IMG]

    Good thinking!
    The next week I checked the time-progress of the nitrate levels to see if the parsley was indeed hogging the barrel, but nothing like that was happening. In fact parsley is actually a very moderate consumer of fertilizers. Another thing I've learned.

    This was the point where I latched onto the “growth inhibitor syndrome”. I realized that only those plants pinned to the drift wood wouldn’t grow, which made me think that something leaching out of the wood is affecting the growth of the plants.

    I did not suspect the wood itself. It’s as common as can be, neither poisonous, nor poisoned, but soon it struck me that the real culprit could only be the “cobbled” substrate.
    It is so squeaky clean . . . not a spot where a microbe colony could survive.
    That’s one of its main advantages, because it’s so easy to clean, but now I realized that I needed a place to grow bacteria in a slight hurry.

    So today I bought a fortune worth of “Siporax”-like ferrules, bagged them in netting and dumped them in the sump, wishing all the beneficial microbes patiently waiting on the side lines a glorious colonisation time for my plant’s benefit.
     

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