Why I don't use turface anymore (with pics)

[63pmp]

Poink said

It seems "free draining" is relatively defined. With finer ingredients there will be more lag before water totally flushes down (no contesting that)...but we are just talking mere seconds difference here (if that).

To me, I see that as an advantage actually. Being a miser, I want the water and fertilizer to have time to adhere before leaving the pot. Waste is waste in my book.

If I want less water, I will use a smaller pot or reduce my soil. Problem solved (also).

"Free draining" means absolutely nothing in a conversation about potting mixes, it is the most useless term in bonsai.

The problem with finer ingredients is that the water does not leave the pot. The finer materials settle to the bottom, or fill the pores made by larger particles and do not drain Smaller pores have a low air filled porosity, this means the pores do not drain, but remain full of water. This is the problem with fine mixes, they simply do not drain, even though you may see the water poring out the bottom of the pot when you irrigate. The saturated zone at the bottom of the pot will be to high, reducing the available oxygen for plant roots.


Paul

Just read Scotts post, and I would add that I think Japanese maples require at least 20% AFP in a 10 cm deep pot. Every species of plant has different needs.

I would also add that porosity changes slightly with particle size, but greatly with particle shape and size distribution.

 

[Poink88]

"Free draining" means absolutely nothing in a conversation about potting mixes, it is the most useless term in bonsai.

The problem with finer ingredients is that the water does not leave the pot. The finer materials settle to the bottom, or fill the pores made by larger particles and do not drain Smaller pores have a low air filled porosity, this means the pores do not drain, but remain full of water. This is the problem with fine mixes, they simply do not drain, even though you may see the water poring out the bottom of the pot when you irrigate. The saturated zone at the bottom of the pot will be to high, reducing the available oxygen for plant roots.

Useless to you maybe...not to me and others it seems.

I agree if the fine is so fine that it really clogs the holes and doesn't drain but in my experience 1/16" grains are big enough to drain. Again, to each his own and my results speak for themselves.

 

[markyscott]

You guys are thinking too hard - whatever is locally available and affordable, go with it. My mix is probably not perfect, but gets the job done just fine.

http://localbonsai.com/diy-bonsai-soil-a-practical-beginners-guide/

Whatever dude. This is why I never advise people what to use in their soil - I will explain the physics and the chemistry to those who are interested. But people will end up using whatever because it's what they've always used. So I say go for it. What do I know - I'm just a yokel with a PhD in geology specializing in computational fluid mechanics, 15 years of industry experience in porous media flow, and 20 years of experience growing bonsai trees. And these ivory tower geeks at UC Davis probably don't know anything about about basic horticulture either:

http://ucanr.edu/sites/eh_ric/newsletters/vol2_no1_winter_199837629.pdf

So use what you like. Any thinking about topics covered in basic undergraduate horticulture classes is probably over taxing. If it works for you it must be good enough.

Scott

 

[Poink88]

Whatever dude. This is why I never advise people what to use in their soil - I will explain the physics and the chemistry to those who are interested. But people will end up using whatever because it's what they've always used. So I say go for it. What do I know - I'm just a yokel with a PhD in geology specializing in computational fluid mechanics, 15 years of industry experience in porous media flow, and 20 years of experience growing bonsai trees. And these ivory tower geeks at UC Davis probably don't know anything about about basic horticulture either:

http://ucanr.edu/sites/eh_ric/newsletters/vol2_no1_winter_199837629.pdf

So use what you like. Any thinking about topics covered in basic undergraduate horticulture classes is probably over taxing. If it works for you it must be good enough.

Scott

Impressive. I knew there is something with all the organized and scientific response. Thanks for all the input Scott!!!

Question. Can my "wick solution" work? I've always thought it will but having your experience and background to either debunk or support it helps me and maybe others. Thanks.

 

[markyscott]

I would also add that porosity changes slightly with particle size, but greatly with particle shape and size distribution.

Porosity is really independent of grain size for rocks with the same sorting.

From Dr. Hiraskai's class at Rice; Flow and Transport in Porous Media I
Geology, Chemistry and Physics of Fluid Transports:

http://www.owlnet.rice.edu/~ceng571/CHAP3.pdf

See page 28.

Also see Jorden, J. R. and Campbell, F. L.: Well Logging I - Rock Properties. Borehole
Environment. Mud and Temperature Logging, SPE of AIME,1984.

Scott

 

[markyscott]

Impressive. I knew there is something with all the organized and scientific response. Thanks for all the input Scott!!!

Question. Can my "wick solution" work? I've always thought it will but having your experience and background to either debunk or support it helps me and maybe others. Thanks.

Wicking will put water in the soil. But the water saturation is a capillary property of the material regardless of how the water gets there. In the end, as Paul noted his previous post, finer grained material will have higher equilibrium water saturations than coarser grained material and the 100% saturated zone at the bottom of the pot will rise higher. This is not optimal in a shallow container, but plants can still grow - just not ... optimally. With great care in watering you can probably attain optimal saturations if you maintain the soil between its field capacity and hygroscopic water saturations but above the wilting point. Challenging. Much easier to use a material whose equilibrium saturations are closer to what you need and water as often as you like.

- Scott

 

[joepa82]

You guys are all stupid! Goons mix is the only way to go. 30% pine bark, 30% table salt, and 39% crushed up flintstone vitamins

 

[davetree]

Useless to you maybe...not to me and others it seems.

I agree if the fine is so fine that it really clogs the holes and doesn't drain but in my experience 1/16" grains are big enough to drain. Again, to each his own and my results speak for themselves.

Do you have any trees in shallow pots yet ? Or are they all in deep pots ? It probably makes a difference. It gets a little dicey when you have a pot that's an inch and a half deep.

 

[davetree]

You guys are thinking too hard - whatever is locally available and affordable, go with it. My mix is probably not perfect, but gets the job done just fine.

http://localbonsai.com/diy-bonsai-soil-a-practical-beginners-guide/

You're not thinking hard enough. But you haven't been at this very long.

Also, to save a few dollars on soil mix is a bad idea. I spent $250 on soil mix components this year. A waste of money ? Cost me about $2 per year per tree. Absolutely worth it. I had lava shipped to me from the west coast. I can't believe that I gave all that money to bonsai nurseries instead of Home Depot !!!

 

[davetree]

Here is a mix of screened turface MVP (1/16 to 1/8", mostly), small akadama and small pumice (both about 1/8 to 3/16"). After repeated waterings the small turface has settled to the bottom. The larger particles of turface have stayed put. I timed the drainage each time and measured the amount drained. The drainage time increased with each watering starting with 4 seconds and increasing to over 30 seconds until it didn't seem to drain very well at all. After 20 waterings the amount of water collected from drainage was half what it was originally. When it's compacted, more water stays in the container.

 

[Poink88]

Wicking will put water in the soil. But the water saturation is a capillary property of the material regardless of how the water gets there. In the end, as Paul noted his previous post, finer grained material will have higher equilibrium water saturations than coarser grained material and the 100% saturated zone at the bottom of the pot will rise higher. This is not optimal in a shallow container, but plants can still grow - just not ... optimally. With great care in watering you can probably attain optimal saturations if you maintain the soil between its field capacity and hygroscopic water saturations but above the wilting point. Challenging. Much easier to use a material whose equilibrium saturations are closer to what you need and water as often as you like.

- Scott

I am sorry I wasn't too clear. I mean installing a wick inside the pot (dangling out the drain holes) to help DRAIN excess water out. It is a way to reduce the water column.

LOL now...you must be shacking your head after reading both "wick" post I made.

Thank you.

 

[Poink88]

Do you have any trees in shallow pots yet ? Or are they all in deep pots ? It probably makes a difference. It gets a little dicey when you have a pot that's an inch and a half deep.

I have nothing in an inch and a half deep pot yet. I have some in 3"-5" deep pots because of their sizes (I have mostly "big" trees).

 

[markyscott]

Here is a mix of screened turface MVP (1/16 to 1/8", mostly), small akadama and small pumice (both about 1/8 to 3/16"). After repeated waterings the small turface has settled to the bottom. The larger particles of turface have stayed put. I timed the drainage each time and measured the amount drained. The drainage time increased with each watering starting with 4 seconds and increasing to over 30 seconds until it didn't seem to drain very well at all. After 20 waterings the amount of water collected from drainage was half what it was originally. When it's compacted, more water stays in the container.

Cool observations of stratification with different size fraction and it's impact on drainage and equilibrium saturations. Keep up the good work!

Scott

 

[Gene Deci]

Wicking will put water in the soil. But the water saturation is a capillary property of the material regardless of how the water gets there. In the end, as Paul noted his previous post, finer grained material will have higher equilibrium water saturations than coarser grained material and the 100% saturated zone at the bottom of the pot will rise higher. This is not optimal in a shallow container, but plants can still grow - just not ... optimally. With great care in watering you can probably attain optimal saturations if you maintain the soil between its field capacity and hygroscopic water saturations but above the wilting point. Challenging. Much easier to use a material whose equilibrium saturations are closer to what you need and water as often as you like.

- Scott

I know people sometimes water their trees by putting wicks into water to soak it up. But some of us put wicks in the bottom of our pots for the opposite purpose. Letting the ends of the wick hang out in the air to dry pulls the water out like a siphon. It really works. I have done a side by side comparison using straight turface in clear plastic saucers about two inches deep. In about a half an hour after soaking by submerging, the saucer with the wick had no visible water on the bottom whereas in the saucer without the wick the water persisted for several hours.

 

[coh]

Here is a mix of screened turface MVP (1/16 to 1/8", mostly), small akadama and small pumice (both about 1/8 to 3/16"). After repeated waterings the small turface has settled to the bottom. The larger particles of turface have stayed put. I timed the drainage each time and measured the amount drained. The drainage time increased with each watering starting with 4 seconds and increasing to over 30 seconds until it didn't seem to drain very well at all. After 20 waterings the amount of water collected from drainage was half what it was originally. When it's compacted, more water stays in the container.

I think what you're establishing here is that one shouldn't use turface as an akadama replacement in a "Boon" mix. There are probably a couple of reasons for this - small size of the turface particles, and the different density of the particles. In other words, turface is much more dense than pumice (and probably somewhat more dense than lava), so all things being equal the turface would tend to settle toward the bottom of the pot.

So what to do? Throw out all turface and never use it again? I suppose that's one option, provided you have other suitable materials that are accessible/cost effective. Another option is to use turface the way others have successfully used it. Mix it with similar-sized, similar density components. Again, I go back to the Julian Adams formula of approximately 70% turface, 20% granite (heavy like turface), 10% bark or peat.

People can talk all they want about porosity, saturated levels, etc, but this type of mix has been proven to work over the years.

Chris

 

[Vance Wood]

How many years does it take to establish that a soil mix is suitable?

 

[coh]

How many years does it take to establish that a soil mix is suitable?

I don't know. Julian has been using his for 30+ years. Is that long enough?

 

[davetree]

I should have titled the thread "What happens when a smaller particle is used in a mostly larger particle mix." It didn't have to be turface it could have been mouse turds. Nothing against turface.

 

[davetree]

How many years does it take to establish that a soil mix is suitable?

Not the point of the thread

 

[Poink88]

I know people sometimes water their trees by putting wicks into water to soak it up. But some of us put wicks in the bottom of our pots for the opposite purpose. Letting the ends of the wick hang out in the air to dry pulls the water out like a siphon. It really works. I have done a side by side comparison using straight turface in clear plastic saucers about two inches deep. In about a half an hour after soaking by submerging, the saucer with the wick had no visible water on the bottom whereas in the saucer without the wick the water persisted for several hours.

Thanks. Exactly what I meant.

I am sorry I wasn't too clear. I mean installing a wick inside the pot (dangling out the drain holes) to help DRAIN excess water out. It is a way to reduce the water column.

LOL now...you must be shacking your head after reading both "wick" post I made.

Thank you.