Differentiating old/dead roots from live ones

[Puja]

I have a question regarding the clipping of old and/or dead roots to help my orchids flourish.

Up to now, I've been dealing with this pretty straightforwardly - are the roots shriveled, dried out, brown or black or otherwise without signs of life from start to end, then I pry them loose and cut them off.

However, as our orchids grow older many of them accumulate a large heap of roots that are neither as nice and healthy looking as the newest roots, nor are they dead. Should I cut these or not, when should I do so, etc? Am I supposed to cut off all the old roots after enough new ones have formed? Am I supposed to get rid of any that does not have a shiny green tip, even if the rest of the root looks healthy?
I've also noticed that often, if roots with dried out or black ends are left alone for a while, as long as some part of the root is still thick and light-coloured, a new offshoot will spring from the live part. Should I still cut these older roots to promote the growth of entirely new roots?

I still feel a bit iffy about cutting off roots that look to be in a bad condition, only to notice upon cutting that they were still entirely green inside.

tl;dr How do I determine which roots to cut to best promote healthy growth?

A related question: as I've always been conservative with cutting the roots, many of the older phalaenopsis in our windowsills have accumulated six or seven levels of dead material as a base, as living roots still extend from the very base of it. It looks a bit untidy as the leaves sit increasingly higher from the substrate (I've been told to always repot with the roots in the same place as before - any above the substrate still on top and any extending into the pot back in).

[Ray]

Why are you routinely trimming roots in the first place?

When I have unpotted and removed the old potting medium during my regular repotting routine, then I remove any roots that are obviously dead and rotted. Done.

Unless your culture is so poor that you are a frequent root-killer, there is no need to remove those that succumb in between repotting jobs. As they decompose, the nutrients stored in them are released to the microorganisms that thrive in the potting medium and to the plant.

[Puja]

Originally Posted by Ray

Why are you routinely trimming roots in the first place?

When I have unpotted and removed the old potting medium during my regular repotting routine, then I remove any roots that are obviously dead and rotted. Done.

Ah, I think I should better explain the context in which I'm asking this because you are jumping to the wrong conclusion. The orchids for which I want to know this information are all at least 7 years old and have been pretty much left alone (aside from repotting which was basically only replacing the spent substrate) and cutting off the flower stalks when they were finished blooming. However since this year a few of them have been struggling. I started googling and saw quite a few posts on this forum where people recommended that older orchids in a bad shape be rid of their dead roots to help revitalise them. I tried to do so but in doing that I ran into the problem as stated in the OP. This is the first time ever, aside from maybe one or two completely black roots, that they have ever had roots removed.

If this is a bad idea altogether, do please tell me that, but I saw so many posts of people suggesting this that I thought it a good idea. It isn't water/food/light/etc. conditions that are putting these plants into a bad shape as they are kept under the same conditions that they always have thrived in.

[WaterWitchin]

Here's what I do, for what it's worth:

Up to now, I've been dealing with this pretty straightforwardly - are the roots shriveled, dried out, brown or black or otherwise without signs of life from start to end, then I pry them loose and cut them off.

Presuming we're talking bark, etc, medium in a pot... I don't pry loose and cut off dead roots unless repotting.

However, as our orchids grow older many of them accumulate a large heap of roots that are neither as nice and healthy looking as the newest roots, nor are they dead. Should I cut these or not, when should I do so, etc? Am I supposed to cut off all the old roots after enough new ones have formed? Am I supposed to get rid of any that does not have a shiny green tip, even if the rest of the root looks healthy?

Short answer to all these questions: No. Older roots may not be as pretty as a new one, but doesn't mean it's not serving its purpose. I'm not as pretty as I was 30 years ago, but still serve a purpose.

I've also noticed that often, if roots with dried out or black ends are left alone for a while, as long as some part of the root is still thick and light-coloured, a new offshoot will spring from the live part. Should I still cut these older roots to promote the growth of entirely new roots?

No. When repotting I only cut off black, rotted, hollow roots. If part is rotted, part is not, I only cut off the rotten part.

I still feel a bit iffy about cutting off roots that look to be in a bad condition, only to notice upon cutting that they were still entirely green inside. tl;dr How do I determine which roots to cut to best promote healthy growth?

Don't cut older roots, only dead ones and/or partial dead ones. When repotting.

A related question: as I've always been conservative with cutting the roots, many of the older phalaenopsis in our windowsills have accumulated six or seven levels of dead material as a base, as living roots still extend from the very base of it. It looks a bit untidy as the leaves sit increasingly higher from the substrate (I've been told to always repot with the roots in the same place as before - any above the substrate still on top and any extending into the pot back in).

If we're talking phals, I repot down to point where I can just barely see the top of highest root on plant below leaves. If it's aerial, leave it.

And by the way... Welcome to Orchid Board!

[King_of_orchid_growing:)]

I will add a few small pieces to this puzzle...

The consensus is not to cut living roots no matter how unattractive they look on the plant and regardless of the age of the plant, and I agree.

What had been said already is true, but this is what I will add.

I don't know what kind of orchid you are referring to because it was not ever mentioned, but I will assume it is an orchid that is fairly commonly grown, (if it isn't, please do correct me if I'm wrong, and please mention what it is so we can have a better understanding of what you're dealing with). The commonly sold orchids available in the hobby usually tend to grow a large amount of roots fairly easily and rather quickly, so cutting living roots on these kinds of orchids will never ever show a person what kind of serious damage cutting living roots can actually do.

It is when a person starts growing orchids that naturally grow very few roots or tends to grow roots slowly that one starts to see how much of a bad idea it really is no matter what kind of orchids they are. Cutting living roots on these kinds of orchids is literally a death sentence.

The other thing is cutting the roots potentially opens up a multitude of surfaces for pathogenic microorganisms to infect the plant. If something does infect your plants, then you will have far bigger problems than aesthetics.

One final thing is...have you ever watched some documentaries about plants? A plant's growing root tips are of significant importance to a plant. There is a small area in the growing root tips that behave like how our neurons fire. The roots are part of how the plant senses its world and it may also be tied to its immune system or health in some way. Have you ever noticed on some of the thinner leafed orchids that if some of the root tips are damaged, the leaf tips also get damaged? There's something to this. Unfortunately, I'm not really sure what the physiological connection is, so I cannot speak about this in detail, but it is something that I have seen and wonder about.

As a grower, I try to be careful not to damage a bunch of roots if possible. This is particularly true because I tend to grow orchids that naturally do not produce a lot of roots or grow roots slowly. Many of these orchids are difficult to obtain, so it is in my best interest to not purposefully damage them as much as possible. Even if some of the orchids I have can grow a ton of roots quickly, I am in the school of thought where it is good to not practice bad habits. You may take what I said for what its worth. These are my

As far as differentiating living roots from dead ones, I like to wet the root mass down thoroughly and do a pull test. If I gently pull on the roots and the velamen layer sloughs off leaving behind the stringy core, then I cut those, these are clearly dead. I leave any living roots alone.

[Ray]

It sounds to me like the biggest issue is residue accumulation in the old medium.

The orchids for which I want to know this information are all at least 7 years old and have been pretty much left alone (aside from repotting which was basically only replacing the spent substrate) and cutting off the flower stalks when they were finished blooming.

Trimming dead roots does nothing to "revitalize" the plant. Repotting it and completely replacing the old potting medium with fresh stuff more frequently will.

[King_of_orchid_growing:)]

If the issue truly is a matter of revitalizing the plant, then, yes, I agree, cutting living roots will not do anything for the plant.

Cutting dead roots will not revitalize the plant either. It is more for the ease of knowing how many living roots you are dealing with so that you can find an appropriate pot size for the plant. It also reduces the amount of potentially problematic microorganisms from flourishing in order to give a struggling orchid a chance to recover.

Potting media that have broken down over time should be replaced and that should help revitalize it a bit.

[Puja]

Thank you all so much for your thorough advice and two cents! I feel a lot better informed about orchids now ^^

As some of you were wondering; I just have a bunch of cheap NoID phals collected or gifted (presumably mostly) from supermarkets or flower shops, with the exception of one which looks to be intergenera (it has broad, flat pseudobulbs with very long, slanting leafblades and small flowers shaped like a phal's). The phal struggling the most is a dwarf plant with dwarf flowers (is it called a colibri due to size or is that a specific subspecies?). All of its leaves have gone limp, its roots have dried out one by one until there were just 3 left and it hasn't seen new growth in over a year. The medium was renewed this spring and when the roots started drying out it has been given water increasingly often (but in smaller doses). Doesn't seem to have helped. It has now been stable for a month or two rather than continuing to deteriorate, though no sign of improvement yet.
I have to say though, since I've done all the reading on this forum and elsewhere, I have started misting the orchids about 6 times a day with distilled water like I do with my ferns and carnivorous plants and most seem to be responding well. Aside from the dwarf they are doing significantly better. The problem is probably the climate - I live in a very dry climate and this year is particularly hot and dry, so they must be losing too much water despite being watered frequently and the more frequent watering with hard water may have also played them parts.

Originally Posted by King_of_orchid_growing:)

As far as differentiating living roots from dead ones, I like to wet the root mass down thoroughly and do a pull test. If I gently pull on the roots and the velamen layer sloughs off leaving behind the stringy core, then I cut those, these are clearly dead. I leave any living roots alone.

Oh yes, I have also noticed this. Thank you for putting that into context.

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