Why Not Have Many Tiny Drainage Holes?

[Deep Sea Diver]

Regarding mesh sizes. Down the rabbit hole I go….!

Shouldn’t the largest mesh size be used consistent with the particle size? Did I miss something?

A small mesh screen size not only has the propensity to clog with debris, but at very slow flow …the tail end of the watering flush, adhesion and cohesion of water to the mesh and itself respectively, in that order, are going to act to resist the water from exiting the pot.

This would tend to hold some water back blocking the screen and restrict air from getting into the pot… until the water held back evaporated (yep, from the bottom area of the pot). Debris clogging the area effectively decreases the effective mesh size, increasing these effects.

The material of the pot isn’t as much of a factor as water binds to itself much more strongly than to either a plastic or ceramic surfaces, and it's the water-water bonds that are being broken in evaporation.

A mesh over small pot holes only complicates the situation.

The issue becomes a non factor as the hole size gets larger and increases as the mesh size decreases…

The goal is to keep water and air flowing freely… up to a point. That point is when there is so much air flow into the pot (and evaporation out) that the perched water table begins to be affected. Which means one would have to water more often. A stronger effect during the warmer weather.

Ok if you are around to baby the trees constantly less ok if you aren’t up to it.

As far as an all mesh bottom goes there are some practical implications, strength, durability and frequency of care. Think about how a nice larger tree would do with a mesh bottom, that needs to be tied down securely, turned weekly and moved for maintenance / tree work etc…. Like these beauties.



Cheers
DSD sends

 

[ShadyStump]

Regarding mesh sizes. Down the rabbit hole I go….!

Shouldn’t the largest mesh size be used consistent with the particle size? Did I miss something?

A small mesh screen size not only has the propensity to clog with debris, but at very slow flow …the tail end of the watering flush, adhesion and cohesion of water to the mesh and itself respectively, in that order, are going to act to resist the water from exiting the pot.

This would tend to hold some water back blocking the screen and restrict air from getting into the pot… until the water held back evaporated (yep, from the bottom area of the pot). Debris clogging the area effectively decreases the effective mesh size, increasing these effects.

The material of the pot isn’t as much of a factor as water binds to itself much more strongly than to either a plastic or ceramic surfaces, and it's the water-water bonds that are being broken in evaporation.

A mesh over small pot holes only complicates the situation.

The issue becomes a non factor as the hole size gets larger and increases as the mesh size decreases…

The goal is to keep water and air flowing freely… up to a point. That point is when there is so much air flow into the pot (and evaporation out) that the perched water table begins to be affected. Which means one would have to water more often. A stronger effect during the warmer weather.

Ok if you are around to baby the trees constantly less ok if you aren’t up to it.

As far as an all mesh bottom goes there are some practical implications, strength, durability and frequency of care. Think about how a nice larger tree would do with a mesh bottom, that needs to be tied down securely, turned weekly and moved for maintenance / tree work etc…. Like these beauties.

View attachment 425093 View attachment 425097

Cheers
DSD sends

I'm not sure I'm following everything you're expressing, but it could be because I haven't had my coffee yet.

I do concur with your first statement on mesh size in that matching mesh size to soil particle size would be the best practice.
HOWEVER, I once got ahead of myself on a repot and realized halfway through that I had no mesh. I cut a section out of an old shop cloth and used that. It was worn thin enough you could see details through it when held up to the light. It didn't seem to impede water flow significantly compared to the mesh, nor did it clog. It likely did construct airflow significantly as the soil seemed to stay wet longer. There are other factors that might have contributed to that, though.

Now I'll go make coffee.

 

[Joe Dupre']

I see people writing about clogging of holes in pot bottoms. I've only been in this hobby 6 years, but I have 70 bonsai and have collected well over 150 trees and have yet to find a pot clogging with debris. I've had pots that drained slowly because of other reasons, but not clogging. If bonsai pots are traditionally made a certain way, chances are the features have evolved for good reasons. Not saying some new way might not be better, but I'm sticking with what has worked in the past.

 

[sorce]

We can't talk about a perched water table without talking about the consistency of rocks used for drainage.

Pipe calculations are under pressure rendering the talk irrelevant.

Perfect Circles in well fired ceramic are a stronger point if anything.

It is all about capillary action and surface tension.

I just made a piece of water stay in a 1/8in hole of 3/16in glazed ceramic. Bubble wands do the same.

A small hole with a wire drains better than the same hole with no wire. No bubbles.

The air, as caught by the large hole and sent through the screen, is of much greater volume and effect than air entering a small hole with no catching mechanism.
Air is like water in that it follows the path of least resistance.
It simply does not travel up small holes.
This effects the decomposition of the soil, air is a necessary part of breakdown.
Brokedown, particules fit thru screen.
No air no breakdown....clog.

To Rest, 4 pages?

Sorce

 

[Deep Sea Diver]

Gosh @Joe Dupre' you are getting quite the collection! .

Drain holes can get clogged, its mostly a matter of degree, with one hole getting clogged up.

… or temporarily clogging happening at the end of a inadequate flush

…or flow slowed way down due to broken down media or root growth.

…Or clogged up during winter storage due inadequate drainage under the pot(s)

Finally due to mychorrizae clogging up drain holes, although this is not on point.

I have seen all these happen, some happen less then others.

We almost lost a nice old conifer at the museum last year due to the central drain hole being stopped up. The tree slowly began to look poorly. When the pot was tipped up to check, there it was. It was the last thing we thought of.

Happy Friday everyone!

DSD sends

 

[HorseloverFat]

I think its just the thickness of the mesh material and the tendency of dirt to stagnate on the edges of the tube and clog as the tube gets longer. Through capillary action, stagnation, stiction etc.
View attachment 425090

You could theoretically make a pot floor where the thickness decreases around the built-in mesh. There shouldn't be any weakness from the mesh making the clay thinner. It's not going to crack in freeze or anything like that. It is more difficult to make (I have an idea though around that) Fuck it, I'll make one.
View attachment 425091

This reminds filtering calcium compounds out of a limed-down mixture.. before boiling with activated charcoal and...

Nevermind... Diviner's Alchemy shit.

But the physics IS correct... this is WHY we filter through funnels...

I can't wait to see what you do

 

[HorseloverFat]

We can't talk about a perched water table without talking about the consistency of rocks used for drainage.

Pipe calculations are under pressure rendering the talk irrelevant.

Perfect Circles in well fired ceramic are a stronger point if anything.

It is all about capillary action and surface tension.

I just made a piece of water stay in a 1/8in hole of 3/16in glazed ceramic. Bubble wands do the same.

A small hole with a wire drains better than the same hole with no wire. No bubbles.

The air, as caught by the large hole and sent through the screen, is of much greater volume and effect than air entering a small hole with no catching mechanism.
Air is like water in that it follows the path of least resistance.
It simply does not travel up small holes.
This effects the decomposition of the soil, air is a necessary part of breakdown.
Brokedown, particules fit thru screen.
No air no breakdown....clog.

To Rest, 4 pages?

Sorce

This is absolutely correct, also...

I figured we are, theoretically. "way out there" by this point..

Super interesting conversation here.

 

[rockm]

Big holes plugged up with a mesh of small holes is obviously better?

For simplicity lets say the substrate is sieved through a certain sized mesh. It (the sifted substrate that consists of particles of a smaller mesh size) is going to fall through any lager sized container holes.

yeah, maybe some smaller particles fall through a mesh, but who cares? That loss isn't enough to make much of a difference, as most of the small particles are trapped in the matrix above...

Smaller drain hole do get clogged by smaller particles anyway. Only have to look at "tie down" holes in better pots. Every time I repot a container that has ununsed tie down holes, inevitably I find a piece of haydite/granite/horticultural sand jammed in it...

Big holes with mesh are superior to self-clogging small holes...

 

[BrianBay9]

yeah, maybe some smaller particles fall through a mesh, but who cares? That loss isn't enough to make much of a difference, as most of the small particles are trapped in the matrix above...

Smaller drain hole do get clogged by smaller particles anyway. Only have to look at "tie down" holes in better pots. Every time I repot a container that has ununsed tie down holes, inevitably I find a piece of haydite/granite/horticultural sand jammed in it...

Big holes with mesh are superior to self-clogging small holes...

Agreed. And it's easier to change a clogged piece of mesh than to unclog a bunch of small holes in a pot.

 

[penumbra]

And it goes on............... I have tried to study this thread entirely but I keep going cross eyed.
I make large holes because its what people want.
I have never had a pot clog up due to the size of the holes, only due to the growing mix.

 

[ShadyStump]

To Rest, 4 pages?

And it goes on............... I have tried to study this thread entirely but I keep going cross eyed.

YES!!!!!
Awesome, isn't it?

 

[Dav4]

Bigger's better... trust me .

 

[NaoTK]

 

[ShadyStump]

And now we're back into NSFW jokes.
Nice!

 

[HorseloverFat]

And now we're back into NSFW jokes.
Nice!

Nine Sandwiches For Walter?

 

[ShadyStump]

Nine Sandwiches For Walter?

Nah, just one, but Walter likes 'em big, just like his holes.

 

[Mikecheck123]

To jump the shark... What if you used a ceramic mesh screen to cross the large hole of a bonsai pot instead of the plastic ones? I know that "ceramic fibers" exist but I know nothing about the technology. But say you can use something like this (something similar to fiberglass mesh but made out of ceramic fibers) to mimic the exact dimensions (thickness and gauge) of the plastic screens we all use...

Or what if you incorporated a ceramic mesh into the manufacture of a ceramic pot...so that this ceramic mesh was the entire bottom of the pot and fired it all together (so the pot looked exactly like a plastic Anderson flat but made entirely of ceramic)?

Again, I know nothing about the ceramics, but I did a quick Internet search and found companies that manufacture something called ceramic honeycomb structures (usually used as filters). (The first picture below.) I think a pot bottom that was made up entirely of a ceramic honeycomb structure like the one in the picture that is shaped like a hexagon might be durable and allow for good drainage? We also already mass-produce inexpensive ceramic soldering blocks that you think could easily be incorporated into the design of mass-produced pots (i.e. the entire bottom of a pot being something like the round ceramic soldering block in the third picture below). But we don't do that. And it sounds like the arguments above against tiny holes are the reason why?

[I'm not thinking about bespoke hand-made pots but a company like Anderson but not Anderson...one that specializes in ceramics and maybe already makes ceramic soldering blocks... could easily produce a pot with an entirely holed bottom like an Anderson flat but made of ceramic.]

This idea, like this whole thread, is attempting to solve a problem that doesn't exist. Large holes plus screens provide perfectly adequate drainage. Nothing to fix.

 

[ShadyStump]

This idea, like this whole thread, is attempting to solve a problem that doesn't exist. Large holes plus screens provide perfectly adequate drainage. Nothing to fix.

Who said there was a problem?
The question was, "why." The discussion led some to experiment. No problem here.

 

[NaoTK]

You learn things by messing around. I made a small one just for fun. The idea of never having to use a screen again is appealing, but this took too long and it looks awful.



The inside is flush, but...


I scooped out the bottom so the mesh is only ~1/16" thick like a screen. I will have to get this into my next firing in April.

 

[ShadyStump]

You learn things by messing around. I made a small one just for fun. The idea of never having to use a screen again is appealing, but this took too long and it looks awful.

View attachment 425283

The inside is flush, but...
View attachment 425284

I scooped out the bottom so the mesh is only ~1/16" thick like a screen. I will have to get this into my next firing in April.
View attachment 425285

I eagerly await the verdict.