testing for moisture/dryness

[VickiC]

Originally Posted by ChasWG

Vicki, I don't even have to ask questions, I'll just read your threads and get all the right answers! You are asking all the same questions I would. Thanks for being there and asking!

[beanluc]

Originally Posted by VickiC

Using Catts only as an example (whose medium should completely dry before rewatering, I understand ??).....how do you keep these roots that are growing in an open and airy medium from drying, turning brown and dieing from thirst, while I am waiting for the medium to dry?

I do have a disclaimer below, but otherwise, dehydration is generally unlikely to kill orchid roots except on very particular types of orchids. It's true that crispy dry roots can break easily if they're agitated or moved, and they can be killed from that physical damage, but even when they have become crackly dry, they will sponge water right up and turn green(ish) and soft when they're wetted (especially if immersed) again, as long as they haven't become detached form the plant.

What kills orchid roots isn't usually drying out, it's either physical damage or suffocation. OK, I grant, that's a massive over-generalization. There certainly are orchids among the (what is it?) 30,000 species (?) which roots will die if allowed to parch. Catts and most other epiphytic/lithophytic/medium-aeration-loving orchids are almost never the ones to be concerned about there, it would be mostly non-fleshy-leafed and/or non-pbulb-having orchids. We're talking terrestrials - and I believe that even a lot of underwatered ones of them die not from the roots up but from the dehydrated leaves/stems down. I believe that in many of those types, roots which become desiccated can still come back to life and convey water up to the plant again as long as the top part of the plant isn't too far gone by that point to even want to draw any water. These plants die when the leaves/stems dry out too far for any possibility of the plant's recovery, not when the roots dry out. The roots are the first part to desiccate. It still takes at least some amount of time for the plant to die if it continues to not be watered.

OK, so, besides those special cases:
For most of the rest of orchids, when the medium is logged with water for lengthy and repeated periods of time, all the airy pores in the medium which the roots would breathe from are filled with water so the roots can't get any air. When this condition is present more or less constantly, the suffocation can kill roots. Also, if there already happens to be dead root material down there from some other cause of death, those roots will start to rot when constantly soggy, and the rot easily spreads to live roots because of the anaerobic conditions down there, supporting populations of unhealthy bacteria.

I just started trying a product called Orchid Champion. It's supposed to be an enzyme which breaks down dead root material into a form that aerobic microorganisms like. The idea is that, you know, it's no substitute for proper watering and medium aeration, but it's supposed to help defend against an over-balance of anaerobic microorganisms down there, and even convert the material (with the help of the healthy, aerobic microorganisms) into food that the plant can take back up. It might help a root-sick plant recover faster. Anybody use this stuff? Like to offer experiences?

BL

[VickiC]

Hi,
I really do appreciate you going into such great detail explaining your answer to me! I understand so much better now!

At the time that I posted my question, I didn't have any particular plant in mind with that issue, but there was one I could have referred to which then had very dry, shriveled brown roots.....my "Epi Kanda Mabel 'Miyao'. I should have taken a photo for an example in reference to my question, and I probably should have, but hindsight is 20/20, they say. I had unpotted it a few days prior to asking the question, then repotted it, even though the roots were dry and rather brittle. I'm happy to say that since then, it has three new roots that I can see (photo attached that I took today). Anyway, that was proof perfect of what you were telling me.

I'll certainly know better what I'm looking at when I'm checking out roots in the future.

Thanks very much for your help,
Vicki

Originally Posted by beanluc

I do have a disclaimer below, but otherwise, dehydration is generally unlikely to kill orchid roots except on very particular types of orchids. It's true that crispy dry roots can break easily if they're agitated or moved, and they can be killed from that physical damage, but even when they have become crackly dry, they will sponge water right up and turn green(ish) and soft when they're wetted (especially if immersed) again, as long as they haven't become detached form the plant.

What kills orchid roots isn't usually drying out, it's either physical damage or suffocation. OK, I grant, that's a massive over-generalization. There certainly are orchids among the (what is it?) 30,000 species (?) which roots will die if allowed to parch. Catts and most other epiphytic/lithophytic/medium-aeration-loving orchids are almost never the ones to be concerned about there, it would be mostly non-fleshy-leafed and/or non-pbulb-having orchids. We're talking terrestrials - and I believe that even a lot of underwatered ones of them die not from the roots up but from the dehydrated leaves/stems down. I believe that in many of those types, roots which become desiccated can still come back to life and convey water up to the plant again as long as the top part of the plant isn't too far gone by that point to even want to draw any water. These plants die when the leaves/stems dry out too far for any possibility of the plant's recovery, not when the roots dry out. The roots are the first part to desiccate. It still takes at least some amount of time for the plant to die if it continues to not be watered.

OK, so, besides those special cases:
For most of the rest of orchids, when the medium is logged with water for lengthy and repeated periods of time, all the airy pores in the medium which the roots would breathe from are filled with water so the roots can't get any air. When this condition is present more or less constantly, the suffocation can kill roots. Also, if there already happens to be dead root material down there from some other cause of death, those roots will start to rot when constantly soggy, and the rot easily spreads to live roots because of the anaerobic conditions down there, supporting populations of unhealthy bacteria.

I just started trying a product called Orchid Champion. It's supposed to be an enzyme which breaks down dead root material into a form that aerobic microorganisms like. The idea is that, you know, it's no substitute for proper watering and medium aeration, but it's supposed to help defend against an over-balance of anaerobic microorganisms down there, and even convert the material (with the help of the healthy, aerobic microorganisms) into food that the plant can take back up. It might help a root-sick plant recover faster. Anybody use this stuff? Like to offer experiences?

BL

[Julysun]

There are Bamboo skewers and wooden coffee stir sticks available by mail order or sold in grocery/discount stores. I prefer the coffee stir sticks myself. Target, Walmart, the dollar stores here all carry one or the other. Also Kroger.

[VickiC]

Thank you!
Vicki

Originally Posted by Julysun

There are Bamboo skewers and wooden coffee stir sticks available by mail order or sold in grocery/discount stores. I prefer the coffee stir sticks myself. Target, Walmart, the dollar stores here all carry one or the other. Also Kroger.

[Ray]

Vicki, sorry for taking so long to respond - three jobs (well, they're done by 7 at most companies) and FRO keeps me way to busy these days.

BL and I seem to be generally on the same page.

As to your catts needing to dry out, that's not true either. The need for a medium to dry out between waterings is not a plant requirement - don't forget they can endure months of saturation during rainy seasons in the wild - it's to allow the "bridging" water (droplets held between particles that block airflow) to be absorbed or evaporate.

[VickiC]

Thanks for your advice, Ray. I've got to remember what you said about root suffocation. I think most of my watering questions basically answer themselves if I can just get my "old person memory" to cooperate by keeping that in mind

By the way.....3 jobs?! Oh my. I know how much in demand you are, so no apology necessary. I always appreciate your replys when it's convenient for you.

Vicki

Originally Posted by Ray

Vicki, sorry for taking so long to respond - three jobs (well, they're done by 7 at most companies) and FRO keeps me way to busy these days.

BL and I seem to be generally on the same page.

As to your catts needing to dry out, that's not true either. The need for a medium to dry out between waterings is not a plant requirement - don't forget they can endure months of saturation during rainy seasons in the wild - it's to allow the "bridging" water (droplets held between particles that block airflow) to be absorbed or evaporate.