Root Death

[K-Sci]

Originally Posted by SouthPark

Thanks for mentioning the size of the scoria and including pics. Roughly pea size is workable.
...
The lower section of the pot has a fair bit of much-larger-size scoria --- eg. 15 mm diameter [pic link]

I see your plant has a nice bud too.

I've used scoria and similar sized fractured slate, but only experimentally. I have a Cymbium splendidum from Odom's that came in the slate, so I purchased a bunch to give it a try. It came in a fixed rate USPS box that was so heavy it barely held together.

My big C. leopoldii 'Sanbar Giant' is now growing in the slate. The plant is so sprawling that it needed an 8" (20cm) pot. That's a lot of rock, a very large deep mass. I rarely give it more than a light sprinkling when i water b/c C. leopoldii doesn't like wet feet. The pot is transparent so it is easy to tell when it is dry. The jury is still out on whether this using such a high volume of slate was a good idea.

-Keith


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---------- Post added at 02:15 PM ---------- Previous post was at 02:06 PM ----------

Originally Posted by Ray

Not all LECA is the same...

Originally Posted by Ray

The stuff that deposits on the surface is one concern, but the stuff that is absorbed and depositing internally should also be considered, as in most brands, even when unwatered for a long time, the interior still contains some liquid, meaning that the solution can be extracted once rewetted.

I purchased a brand of LECA that appearedat the time to be mainstream and widely used in horticulture (this impression could be wrong). It's the Mother Earth Products HGC714114 Hydroton Original. I hope it's good for orchids because I have a huge bag of it. Ray, do you know anything about this product?

Incidentally, it doesn't seem to need washing (very little powder washed out) but I could be wrong. I believe I saw something on your website months ago about understandable residues.

-Keith

[Ray]

Originally Posted by K-Sci

I purchased a brand of LECA that appeared at the time to be mainstream and widely used in horticulture (this impression could be wrong). It's the Mother Earth Products HGC714114 Hydroton Original. I hope it's good for orchids because I have a huge bag of it. Ray, do you know anything about this product?[/FONT]

Incidentally, it doesn't seem to need washing (very little powder washed out) but I could be wrong. I believe I saw something on your website months ago about understandable residues.

-Keith

It is my understanding - word-of-mouth only - that Hydroton is no longer manufactured. Whether that is incorrect, that "Mother Earth" had some privately labeled (I used to have an Atami product labeled for me), or they bought up remaining inventory, I have no idea, but since moving to NC, it was the only brand available to me, and I used it without issue. My local hydroponics supply house now has Cyco Platinum Series Hydro Clay, also out of Germany, which looks a lot like the PrimeAgra of old.

As far as cleaning is concerned, there are three potential sources of contamination. Dust certainly is one, but that's easy to deal with - even potting dry, it will rinse out of the pot (although I don't do that). The other two are of more concern - binders and processing aids used to create the pellets in the first place is one. If selected properly and the pellets are fired correctly, they are lost, but if not, they may be retained as alkaline salts, which we'd like to get rid of. Secondly, the manufacturing process is dusty, as we have recognized, but in order to package the product quickly, it has to cool, and that often means quenching with water, and in all likelihood, that is non-potable water containing who-knows-what.

Fortunately, an extended soak with copious water will do the trick, and if salts are in the pellets, adding calcium nitrate and/or Epsom Salt to the water accelerates the extraction and "nutrifies" the pellets. (Think of it as water softening in reverse - instead of using Na to replace the Ca and Mg in the solution, we use the Ca and Mg to replace the Na in the LECA.)

In all honesty, I have no idea how well the manufacturers do, but this is a "better safe than sorry" effort I always follow.

[Dimples]

Keith,
Throw me into a pool and I can hold my breath for awhile and come out just fine. Keep me underwater long enough and I'll die. Another person may be able to stay underwater longer and come out ok.

Same thing goes for plants. The length of time it will take to kill roots via submersion will depend on the species, and on the health of the individual plant, but all non-aquatic plants are adapted to tolerate and survive a flooding event of some duration (could be 5 min, 5 hours, 5 days, etc.). It seems your orchid is adapted to survive at least 24 hours of submersion when in good health.

Now, make me breath in a mixture of 95% air and 5% liquid water permanently? I'll die slowly as my lungs fill up with water.

Roots growing in conditions that are slightly wetter than the range they are adapted to can't maintain function, decline in health, and eventually die. The speed of root death depends on a variety of other factors, but in general the further the conditions are outside of the range of tolerance, the faster the roots will die. New roots adapted to the new conditions can grow, but the old ones won't make it. That's why the grasslands in Africa can survive the annual drought/flooding cycles. They grow new roots very quickly once soil conditions change in either direction. The old roots can keep them going temporarily as they slowly die, but they'll need to grow new roots if they want to survive the new conditions.

The need for the new roots comes down to gas exchange - it doesn't work the same way underwater as it does in an airy media, and soggy media is the crap side of both conditions so almost no roots will tolerate it for long (that's why bog plants are so neat!).

Time, temperature, plant health, and other factors contribute to the speed of root death, but the primary factor in moisture-related root death is limited gas exchange.

Now, the real question is - are the roots dying while the plant looks on in horror, or is the plant aborting the functionally-deficient root system on purpose? :P

[SouthPark]

Originally Posted by K-Sci

I see your plant has a nice bud too. I've used scoria and similar sized fractured slate, but only experimentally.

Thanks for mentioning slate. The local scoria here doesn't have any sharp bits. Has slate got any sharp bits or sharp edges? Not that I mind at all. As long as it works, then that is fine.

I have seen one orchid nursery use just regular rocks quite successfully. Maybe 10 to 15 mm average diameter rocks and/or pebbles. They had their own workable watering schedule obviously.

[Rwhb12]

Originally Posted by K-Sci

Sphagnum has antiseptic qualities that could prevent the growth of aerobic microbes and thereby prevent or delay root suffocation.

-Keith

I never heard of this before - do all mosses have the same property?

Russ

[Ray]

Originally Posted by Rwhb12

I never heard of this before - do all mosses have the same property?

Russ

Not all.

[Shadeflower]

Originally Posted by Dimples

Keith,
Throw me into a pool and I can hold my breath for awhile and come out just fine. Keep me underwater long enough and I'll die. Another person may be able to stay underwater longer and come out ok.

Same thing goes for plants. The length of time it will take to kill roots via submersion will depend on the species, and on the health of the individual plant, but all non-aquatic plants are adapted to tolerate and survive a flooding event of some duration (could be 5 min, 5 hours, 5 days, etc.). It seems your orchid is adapted to survive at least 24 hours of submersion when in good health.

Now, make me breath in a mixture of 95% air and 5% liquid water permanently? I'll die slowly as my lungs fill up with water.

Roots growing in conditions that are slightly wetter than the range they are adapted to can't maintain function, decline in health, and eventually die. The speed of root death depends on a variety of other factors, but in general the further the conditions are outside of the range of tolerance, the faster the roots will die. New roots adapted to the new conditions can grow, but the old ones won't make it. That's why the grasslands in Africa can survive the annual drought/flooding cycles. They grow new roots very quickly once soil conditions change in either direction. The old roots can keep them going temporarily as they slowly die, but they'll need to grow new roots if they want to survive the new conditions.

The need for the new roots comes down to gas exchange - it doesn't work the same way underwater as it does in an airy media, and soggy media is the crap side of both conditions so almost no roots will tolerate it for long (that's why bog plants are so neat!).

Time, temperature, plant health, and other factors contribute to the speed of root death, but the primary factor in moisture-related root death is limited gas exchange.

Now, the real question is - are the roots dying while the plant looks on in horror, or is the plant aborting the functionally-deficient root system on purpose? :P

I agree with everything you say, particularly that it depends on the orchid...

Like this next orchid is being grown in an enclosed terrarium with no ventilation, temp down to 12 degrees and roots submerged in water all the time.

I would not recommend anyone do it but this is a millieri hybrid...

It can tolerate cold + wet but maybe it is just this particular hybrid. The roots are still going strong after a year but I think they might go this year. I don't think the plant is deteriorating. I showed the latest lead to show since being giving max water for the past year it has decided to get a bit bigger on the latest bulb. But this is a bit of an experimenting plant. I've been experimenting with different ferts too and although the bulb has grown bigger I don't know how good it is doing. Anyway that isn't too imortant for this post.

[K-Sci]

Originally Posted by Rwhb12

I never heard of this before - do all mosses have the same property?

Russ

I'm sure they don't. I know that sphagnum does, but don't know of any others being said to have antiseptic qualities as well. By antiseptic, I don't mean it can be used a topical treatment for people, but only that it is very resistant to rot.


You can google the topic to find references to use in food, but I was unable to find a paper for you on the usage as a potting media.


-Keith

[Ray]

Actually, sphagnum has been used on wounds because of its antiseptic properties.

How Humble Moss Healed the Wounds of Thousands in World War I | Science | Smithsonian Magazine

[K-Sci]

Originally Posted by Ray

Actually, sphagnum has been used on wounds because of its antiseptic properties.

How Humble Moss Healed the Wounds of Thousands in World War I | Science | Smithsonian Magazine

Wow! This almost hurts just to read.

"Desperate to get their hands on something sterile that would keep wounds clear of infection, doctors started getting creative. They tried everything from irrigating the wounds with chlorine solutions to creating bandages infused with carbolic acid, formaldehyde or mercury chloride, with varying degrees of success. But in the end, there simply wasn’t enough cotton—a substance that was already in high demand for uniforms and its recently discovered use as an explosive—to go around."

BOOM!
-Keith