New roots for new mix.

[Stone]

I don't think there is any one single REAL reason why an aged potting mix will inhibit root growth.[/

Maybe not but the answer must be less complicated than we might think considering how wide spread this phenomenon is. It dosen't seem to be affected by different media either or water or air or fertilizer. But it just happens time and time again. In fact I doubt its even a combination of factors.
I didn't really expect to get an absolute indication. I think the Boron thing as Roth mentioned or the hormone mobilization MIGHT be the key?

 

[Rick]

Case #1 A compot of 4 bellatulums which did well over summer, then slowed down in autumn and stopped by winter. and thats what you would expect. then they were placed on bottom heat under lights and went into suspened animation until last week when I repotted them into thumb pots and within 3 DAYS!!!!!! new roots on three of them!!! The mix was basically the same.

Mike.

Mike When you say the mix was basically the same do you mean its the same type of mix or you just moved them in old mix to new pots?

If you didn't change the mix then you might consider the aeration/compaction issues. Which can change chemistry pretty fast too.

If you changed out the mix (even if its the same type as previous), then all kinds of things got changed.

 

[Rick]

Maybe not but the answer must be less complicated than we might think considering how wide spread this phenomenon is. It dosen't seem to be affected by different media either or water or air or fertilizer. But it just happens time and time again. In fact I doubt its even a combination of factors.
I didn't really expect to get an absolute indication. I think the Boron thing as Roth mentioned or the hormone mobilization MIGHT be the key?

You have a lot of mounted plants. If they stop growing roots do you remount them to stimulate new roots? Probably not. They probably develop roots on the same mount or basket for years on end with some seasonal ebb/flow. And since there is no mix around the roots, how come they don't experience nutritional (boron for instance) deficiencies like a potted plant in mix supposedly would. Similarly where is the hormonal mobilization coming from for a mounted plant? These were the questions and observations which pushed me to try baskets for paphs after years of trial and error with various pots and mix combinations.

In comparison to how good open rooted plants do (mounted/baskets/semihydro) for years without repotting, I would look more towards some type of inhibitory effect from old mix in potted conditions.

I did a few side by side tests of basket versus potted plants using the exact same ratios of moss/grave/sand. The baskets won hands down for root growth. But I can't tell why/what/how the extra aeration is doing to the chemistry or biology of the media.

 

[Stone]

If you changed out the mix (even if its the same type as previous), then all kinds of things got changed.

Yes I changed the mix, so what are these all kinds of things? The old mix was not broken down, pH was about the same.

 

[Stone]

You have a lot of mounted plants. If they stop growing roots do you remount them to stimulate new roots? Probably not. They probably develop roots on the same mount or basket for years on end with some seasonal ebb/flow. And since there is no mix around the roots, how come they don't experience nutritional (boron for instance) deficiencies like a potted plant in mix supposedly would. Similarly where is the hormonal mobilization coming from for a mounted plant? These were the questions and observations which pushed me to try baskets for paphs after years of trial and error with various pots and mix combinations.

In comparison to how good open rooted plants do (mounted/baskets/semihydro) for years without repotting, I would look more towards some type of inhibitory effect from old mix in potted conditions.

I did a few side by side tests of basket versus potted plants using the exact same ratios of moss/grave/sand. The baskets won hands down for root growth. But I can't tell why/what/how the extra aeration is doing to the chemistry or biology of the media.

For the mouned plants the environment is totally different than inside a pot. These are what I regard as true epiphytes with photosynthetic root tips etc like Phals and Catts etc. What's more they're not surrounded by plastic and constant moisture so its hard to compare the two. Paphs growing in trees are really just in the same moss and humus as the ones on the ground/rocks.
Maybe their (true epiphytes) roots have evolved in a totally different manner than the ''humus epiphytes'', and are not subject to the same nutritional requirements? I don't know. BUT.. I have seen the same thing in repotted Catts as well which points to an inhibitor of some sort from the aged mix as you said.
But also repotting catts does damage the roots and this could cause the hormone stimulation.
I'm not saying that the potted plant doesn't grow seasonal roots..of course it does, but what I'd like to know why new roots are formed so quickly after repotting and it can be a matter of DAYS after it has moved to a fresh mix even after no root activity for many weeks or months!!
Something is telling the plant ''OK you can go ahead and root!!!'' I should add that top growth seems to keep moving slowly on regardless. Which points to more chemical shenanigans in the pot

 

[Rick]

Yup on a lot of your observations in your last post but also consider that I have mounted and baskets of Dendrobiums, Bulbophylums, Catesetums, Gongoras, ...all "true epiphytes" with non photo synthetic roots. Also several paph species like sanderianum and henryanum will be attached to cliff faces with roots (non-photosynthetic) totally exposed to sun and air (not burried in humus). My basket sanderianums have jumped way ahead since coming out of pots.

The phal example is interesting in that before K lite I could never keep a phal in a pot no matter how careful I controlled watering. But mounted they do just fine (but much better since K-lite). But since K lite I have several phals (like that mannii I just posted) that have been in the same pot of moss (or bark in a few other cases) for 2 years now. And still growing leaves and roots. Granted there are lots of roots developing outside of the substrate so for all intents and purposes they are "mounted" on a pot that happens to be full of some old mix. But at least now they don't seem to be inhibited by whatever chemical highjinx are going on in the pots.

 

[SlipperFan]

...The phal example is interesting in that before K lite I could never keep a phal in a pot no matter how careful I controlled watering. But mounted they do just fine (but much better since K-lite). But since K lite I have several phals (like that mannii I just posted) that have been in the same pot of moss (or bark in a few other cases) for 2 years now. And still growing leaves and roots. Granted there are lots of roots developing outside of the substrate so for all intents and purposes they are "mounted" on a pot that happens to be full of some old mix. But at least now they don't seem to be inhibited by whatever chemical highjinx are going on in the pots.

How do you know what's going on in the pot unless you take the plant out of it?

 

[Ray]

My view is a bit more basic.

On a cellular level, roots tailor themselves to function optimally in the environment into which they grow. That is the key to survival.

Change the environment around the roots, and the current ones may no longer be optimal, so the plant does what it can to correct that, by growing new ones.

 

[Stone]

The semi hydro folk with clay balls have about the simplest system, and they run substrates for years without needing to change substrate for root growth

Yes after seeing some of root sysetems produced ( I think it was espice's bellatulum ) I sometimes think it might be the way to go--at least with some spp. In completely inorganic media, at least you wont have the potential (and unseen) chemical changes going on as with organic mixes.

In fact that's a good subject for a new thread!?!?!?!?!?!:rollhappy:

 

[Rick]

How do you know what's going on in the pot unless you take the plant out of it?

Agreed. The roots still in media may be dead and gone, and the plant is just using the pot as a mount, like any other piece of bark. But what's going on in the pot seems to be irrelevant these days compared to the past. In years past, potted phals never grew new roots (above or below the media) and when they looked stressed, I pull them out of the pots generally to find a pretty traumatized plant.

Now they are never sick. They just keep getting new leaves and roots (granted usually above the media though occasionally I do see new roots heading into the media). So I don't have any reason to take them out of the pots for root inspection or repotting. If they are in clay plots then I worry more about breaking and tearing roots that have attached to the clay pot.

 

[SlipperFan]

Agreed. The roots still in media may be dead and gone, and the plant is just using the pot as a mount, like any other piece of bark. But what's going on in the pot seems to be irrelevant these days compared to the past. In years past, potted phals never grew new roots (above or below the media) and when they looked stressed, I pull them out of the pots generally to find a pretty traumatized plant.

Now they are never sick. They just keep getting new leaves and roots (granted usually above the media though occasionally I do see new roots heading into the media). So I don't have any reason to take them out of the pots for root inspection or repotting. If they are in clay plots then I worry more about breaking and tearing roots that have attached to the clay pot.

Pretty interesting. My problem with that is that Phal roots outside pots get all tangled up in each other and want to go into their neighbor's pots. Gets pretty messy.

 

[emydura]

Pretty interesting. My problem with that is that Phal roots outside pots get all tangled up in each other and want to go into their neighbor's pots. Gets pretty messy.

I know exactly what you mean.

 

[Ray]

I'm not going to go back and reread this entire thread, so if this is a repeat, I apologize in advance.

I think another reason we see new root growth after a repot is that we likely damaged the existing roots in the process, which probably elicits a "save yourself" response to produce new ones.

 

[Ray]

Pretty interesting. My problem with that is that Phal roots outside pots get all tangled up in each other and want to go into their neighbor's pots. Gets pretty messy.

Upon realizing that LECA wicks so well, you don't get a "soppy core" in the pot, I started moving my phals into pots as big as their leaf spans (if I can find large enough pots). Ever since doing so, I get no aerial roots whatsoever - they all just go down into the medium.

 

[SlipperFan]

Upon realizing that LECA wicks so well, you don't get a "soppy core" in the pot, I started moving my phals into pots as big as their leaf spans (if I can find large enough pots). Ever since doing so, I get no aerial roots whatsoever - they all just go down into the medium.

Interesting. Are you using your regular S/H plastic pots or something different?

 

[Ray]

Regular S/H pots, Dot

 

[newbud]

Hey Rick - Tell the folks about that lady in Tenn. that never changes nothing for 50 years and all her orchids are fine.

 

[Rick]

Hey Rick - Tell the folks about that lady in Tenn. that never changes nothing for 50 years and all her orchids are fine.

I've mentioned her several times Jack.

It's not that she never changes anything, but she never fertilizes. I know she has repotted many things over the years (especially as the chids out grow pots). But in many cases some things never do get repotted, and the pots crack with the plants rooting into the benches.