Most important components for bonsai?

[JonW]

I'm not talking about skills etc, but the material components for good growth. For example...

• Inorganic soil: Lava, pumice and turface, which has a balance of drainage and holding moisture. Turface increases CEC. I might try American Bonsai Supply's Mini
• Fertilizer: I use dyna gro foliage pro 2x a week at half strength, and some CRF in the spring. Currently, I use Osmocote Plus, but I might switch to something organic, like Jobes (and while I don't trust Miracle Grow, their newer organic products look decent). Something pelleted so it doesn't clog up my soil.
• Humic Acid: I just started using this, so I haven't seen an effect yet, but my understanding is it can lower the PH making ferts more absorbable and increase CEC helping nutrients hang around longer in the soil, thus requiring less ferts and reducing the salt content, which facilitates water uptake with transpiration and consequently photosynthesis and healthy growth.

I know other people use other additives, such as...

• Chelating agents: I think dyna gro has most micronutrients in sufficient amounts and available forms.
• Micronutrients: As I said above, I think I have most covered. Though I don't think Dyna Gro has boron, which I was just reading about in a plant physiology textbook. I know a lot of people add calcium.
• PGR: I've experimented with this briefly on a few test plants, but not certain of the outcome.
• Mycorrhizae: I tend to think the spores from nature will make their way into bonsai, but I also get the point that they may be less prone to thrive in inorganic soil, if we use chemical ferts, if the soil humidity is less consistent... and if you repot frequently, so I could imagine there could be some benefit to certain plants.
• Bacteria: same as above... I think mycelium and bacteria are reasons to consider not bare-rooting plants, especially once they have an established nebari/root ball. Many of my plants are too young and get bare rooted each repotting.
• PH+/-: as I mentioned in regard to humic acid, making ferts more available allowing you to reduce the quantity you use would seem beneficial to transpiration and photosynthesis, but I haven't gotten into measuring and adjusting my water PH.
• Rain water: I've thought about getting a barrel, but I have limited space. There are benefits like reducing chlorine would could harm your soil ecosystem, but tap water has important nutrients.
• Type of pot: pond basket or bonsai bag for air pruning? Nursery pot because it warms up the roots for faster growth? Unglazed ceramic for water wicking? Plaster/Mica for longevity? Some people swear by the type of pot they use. I have mostly plastic bonsai pots but may try some bonsai bags or pond baskets, especially if I decide to put a plant in the ground and want the pond basket to facilitate digging it up.
• Other?

I know some of you use all the above and others was to keep it simple, but wondering what you think makes the biggest benefit.

 

[Adair M]

I'm not talking about skills etc, but the material components for good growth. For example...

• Inorganic soil: Lava, pumice and turface, which has a balance of drainage and holding moisture. Turface increases CEC. I might try American Bonsai Supply's Mini
• Fertilizer: I use dyna gro foliage pro 2x a week at half strength, and some CRF in the spring. Currently, I use Osmocote Plus, but I might switch to something organic, like Jobes (and while I don't trust Miracle Grow, their newer organic products look decent). Something pelleted so it doesn't clog up my soil.
• Humic Acid: I just started using this, so I haven't seen an effect yet, but my understanding is it can lower the PH making ferts more absorbable and increase CEC helping nutrients hang around longer in the soil, thus requiring less ferts and reducing the salt content, which facilitates water uptake with transpiration and consequently photosynthesis and healthy growth.

I know other people use other additives, such as...

• Chelating agents: I think dyna gro has most micronutrients in sufficient amounts and available forms.
• Micronutrients: As I said above, I think I have most covered. Though I don't think Dyna Gro has boron, which I was just reading about in a plant physiology textbook. I know a lot of people add calcium.
• PGR: I've experimented with this briefly on a few test plants, but not certain of the outcome.
• Mycorrhizae: I tend to think the spores from nature will make their way into bonsai, but I also get the point that they may be less prone to thrive in inorganic soil, if we use chemical ferts, if the soil humidity is less consistent... and if you repot frequently, so I could imagine there could be some benefit to certain plants.
• Bacteria: same as above... I think mycelium and bacteria are reasons to consider not bare-rooting plants, especially once they have an established nebari/root ball. Many of my plants are too young and get bare rooted each repotting.
• PH+/-: as I mentioned in regard to humic acid, making ferts more available allowing you to reduce the quantity you use would seem beneficial to transpiration and photosynthesis, but I haven't gotten into measuring and adjusting my water PH.
• Rain water: I've thought about getting a barrel, but I have limited space. There are benefits like reducing chlorine would could harm your soil ecosystem, but tap water has important nutrients.
• Type of pot: pond basket or bonsai bag for air pruning? Nursery pot because it warms up the roots for faster growth? Unglazed ceramic for water wicking? Plaster/Mica for longevity? Some people swear by the type of pot they use. I have mostly plastic bonsai pots but may try some bonsai bags or pond baskets, especially if I decide to put a plant in the ground and want the pond basket to facilitate digging it up.
• Other?

I know some of you use all the above and others was to keep it simple, but wondering what you think makes the biggest benefit.

Very little of your list matters. I don’t store rainwater. I’ve never applied humic acid. I’ve never added michrozzae. Never used bags. Never even heard of PGR...

keep it simple, man.

I use inorganic soil and organic fertilizer. I don’t use turface.

what’s more important than any of the “stuff” is attention to detail about what’s going on with your trees, and knowledge of what to do, and WHEN to do it.

 

[JonW]

Very little of your list matters. I don’t store rainwater. I’ve never applied humic acid. I’ve never added michrozzae. Never used bags. Never even heard of PGR...

keep it simple, man.

I use inorganic soil and organic fertilizer. I don’t use turface.

what’s more important than any of the “stuff” is attention to detail about what’s going on with your trees, and knowledge of what to do, and WHEN to do it.

I agree that the most important thing is timing. That's something I'm always attending to and trying to keep track of the effects, as well as getting better at just listening to the trees. As I get better at this, I seem to naturally add to the things I do - I don't experience it as complexity, but a natural progression. I went from indoor plants in potting soil to outdoor bonsai benches, inorganic soil, liquid and CRF fert, over the course of some years. I think that stuff is simpler than the timing! Like I said in the original post, I figured I'm doing more than some people (who'd consider what I do to be unnecessarily complex) while others have a much more scientific approach - I'm curious to see opinions like yours as well as what others think is essential that I am not yet doing.

 

[BobbyLane]

I had the formula written down on a piece of paper somewhere, give me a moment

 

[coh]

Never even heard of PGR...

Me neither. @JonW , what does that stand for? Some kind of growth regulator?

The water stuff...most municipal water systems are OK for most trees. They do tend to adjust the pH to be somewhat on the high side (7.5 - 8.0) to protect pipes, but whether that has a significant negative impact on your plants depends on many things - what types (and how much) dissolved stuff is in the water, types of trees, etc. I've played around with modifying the pH of my tap water during winter since I sometimes have foliage problems on my tropicals. I've used sulfuric acid (basically battery acid from the auto store) and vinegar. Vinegar is obviously safer but if you're reasonably careful, the battery acid is fine (but it takes only a tiny bit to adjust a gallon or two of water). Honestly, though, I've never noticed any significant impact.

Some day I might put together a rain capturing system. Problem is, I go through a lot of water and would need a lot of storage. I might wind up just using it for some plants that seem particularly sensitive. But keep in mind that rainwater has it's own issues. You can wind up with contaminants (from a roof). Rain water is also very pure with almost no mineral content, and bonsai soil is pretty inert so you have to make sure to provide the plants with all the minerals they need via fertilizer.

 

[JonW]

Me neither. @JonW , what does that stand for? Some kind of growth regulator?

The water stuff...most municipal water systems are OK for most trees. They do tend to adjust the pH to be somewhat on the high side (7.5 - 8.0) to protect pipes, but whether that has a significant negative impact on your plants depends on many things - what types (and how much) dissolved stuff is in the water, types of trees, etc. I've played around with modifying the pH of my tap water during winter since I sometimes have foliage problems on my tropicals. I've used sulfuric acid (basically battery acid from the auto store) and vinegar. Vinegar is obviously safer but if you're reasonably careful, the battery acid is fine (but it takes only a tiny bit to adjust a gallon or two of water). Honestly, though, I've never noticed any significant impact.

Some day I might put together a rain capturing system. Problem is, I go through a lot of water and would need a lot of storage. I might wind up just using it for some plants that seem particularly sensitive. But keep in mind that rainwater has it's own issues. You can wind up with contaminants (from a roof). Rain water is also very pure with almost no mineral content, and bonsai soil is pretty inert so you have to make sure to provide the plants with all the minerals they need via fertilizer.

Yes, PRG is plant growth regulator.

Not that I plan to do this, nor do I think it'd be practical but, about a year ago, I saw a youtube video where a guy made his own well. If I recall, he used an auger or something to dig out a hole wide enough for a 4-inch PVC, backfilled with some gravel to filter out dirt, and dropped in a pump. I thought that was pretty cool and would be an interesting experiment if I had the space for it. We are by a river, so the water level is just below my foundation.

So what is your regimen - slight adjustments to tap water, and fertilizer? Inorganic soil?

 

[coh]

Yes, PRG is plant growth regulator.

Not that I plan to do this, nor do I think it'd be practical but, about a year ago, I saw a youtube video where a guy made his own well. If I recall, he used an auger or something to dig out a hole wide enough for a 4-inch PVC, backfilled with some gravel to filter out dirt, and dropped in a pump. I thought that was pretty cool and would be an interesting experiment if I had the space for it. We are by a river, so the water level is just below my foundation.

So what is your regimen - slight adjustments to tap water, and fertilizer? Inorganic soil?

I started out (about 8-9 years ago) using turface-based soils. Basically a mix of turface, poultry grit and bark. I had OK results but gradually transitioned over to the "Boon" mix of akadama, pumice, lava. Sometimes I throw in some bark, sometimes some horticultural charcoal. I've had good results using this mix. It is quite expensive to have bags of the components shipped here so I understand people who are looking for cheaper ingredients. If akadama became too expensive or unavailable I'd just go back to using more bark and charcoal (maybe some DE) and would probably be fine.

I don't adjust my tap water at all during the summer. Last winter I did start using vinegar to lower the water pH for my tropicals (a couple of willow leaf ficus and a rain tree). The ficuses always start to look ratty by the end of the winter no matter what I do so the lowered pH hasn't been a magic bullet. I do have a few trees that start to look "autumnal" earlier than they should and that could very well be due to water pH issues. But they don't seem to be weakening over time.

Fertilizer...I use a combination of "blue powder" fertilizers (miracle grow type stuff, the one I use most is called growmore I think). I also use tea bags with organic stuff. I don't use any of the standard bonsai brands like bio-gold, I just buy bags of components like cottonseed meal, blood meal, etc and mix up my own. Generally use the inorganics about once a week and just add the tea bags when I get around to it.

 

[M. Frary]

The tree is!

 

[JonW]

I started out (about 8-9 years ago) using turface-based soils. Basically a mix of turface, poultry grit and bark. I had OK results but gradually transitioned over to the "Boon" mix of akadama, pumice, lava. Sometimes I throw in some bark, sometimes some horticultural charcoal. I've had good results using this mix. It is quite expensive to have bags of the components shipped here so I understand people who are looking for cheaper ingredients. If akadama became too expensive or unavailable I'd just go back to using more bark and charcoal (maybe some DE) and would probably be fine.

I don't adjust my tap water at all during the summer. Last winter I did start using vinegar to lower the water pH for my tropicals (a couple of willow leaf ficus and a rain tree). The ficuses always start to look ratty by the end of the winter no matter what I do so the lowered pH hasn't been a magic bullet. I do have a few trees that start to look "autumnal" earlier than they should and that could very well be due to water pH issues. But they don't seem to be weakening over time.

Fertilizer...I use a combination of "blue powder" fertilizers (miracle grow type stuff, the one I use most is called growmore I think). I also use tea bags with organic stuff. I don't use any of the standard bonsai brands like bio-gold, I just buy bags of components like cottonseed meal, blood meal, etc and mix up my own. Generally use the inorganics about once a week and just add the tea bags when I get around to it.

When I started, I also used Turface, granite (poultry grit) and bark. I think they call it's Al's Gritty Mix. I still have a Crepe Myrtle in that, but I'm also not a big fan. The granite holds too much water on its surface and I have mixed feelings about bark. Akadama costs more than I'd like to spend and I've had some tropicals do fine over summer, then start dropping leaves overwinter when I'd really rather not repot. However, I found that the akadama, while gritty on top, had broken down at the bottom of the pot - it dried out fast enough during summer, but was holding too much water for winter.

I have a few plants in lava, pumice, bark and charcoal, and they seem to be doing well. I think I'm going to try the American Bonsai Supply mini soil, which isn't to bad at $9 a gallon if you buy enough for free shipping. I've mixed my own, but I don't have a ton of time, and I tend to do it in my basement in the winter (to prep for spring repotting) which makes a big mess. I don't actually think mixing my own save much money - the cheapest ingredient was Turface MVP at $25 for 50-pounds, and half the bag was too fine. I've been going threw 1-2 bags a year plus equal amounts of pumice and lava. The pre-mixed stuff just makes more sense to me currently.

My ficus tend to do fine in the winter - the Benjamina pouts a little sometimes, but I just sold it anyway. But I sometimes have the opposite issue with leaves turning "autumnal." Especially last year, all the in-ground trees had lost their leaves and my broadleaf deciduous trees were still green. Many of them, I keep under my storm doors (I don't have space to kneel them in and cover with mulch), and I had to bring them in before they dropped their leaves. Not sure what that was about...

 

[just.wing.it]

Patience is the most important component for bonsai.




Edit:......hehe, look at me getting all fortune cookiey haha!

 

[SantaFeBonsai]

I used humic acid once on a western juniper,,, it turned 100% juvenile for 6 months lol.

 

[JonW]

I used humic acid once on a western juniper,,, it turned 100% juvenile for 6 months lol.

Oh no! I've heard its easy to overdo it. I used a moderate amount and didn't notice any immediate ill or beneficial effects.

 

[0soyoung]

Inorganic soil: Lava, pumice and turface, which has a balance of drainage and holding moisture. Turface increases CEC. I might try American Bonsai Supply's Mini

Per my internet sources

• Turface CEC = 35-ish
• lava CEC = 15 to 45
• pumice CEC = 75-ish

I agree with Adair M's point of keeping it simple.

I like to spend my spare time (away from bonsai) wandering the local forests, and thinking about ...

I use nothing but Turface and Osmocote Plus in modest amounts. Volunteer mico shows up in my pots/baskets. I wash and reuse my MVP. I have 50-some different species in my collection plus a dozen or so more that I didn't find interesting enough to replace after I mistakenly killed them.
Organic fertilizers are shit as far as I am concerned.


I do fiddle with PGRs.

 

[JonW]

Per my internet sources

• Turface CEC = 35-ish
• lava CEC = 15 to 45
• pumice CEC = 75-ish

I agree with Adair M's point of keeping it simple.

I like to spend my spare time (away from bonsai) wandering the local forests, and thinking about ...

I use nothing but Turface and Osmocote Plus in modest amounts. Volunteer mico shows up in my pots/baskets. I wash and reuse my MVP. I have 50-some different species in my collection plus a dozen or so more that I didn't find interesting enough to replace after I mistakenly killed them.
Organic fertilizers are shit as far as I am concerned.


I do fiddle with PGRs.

Interesting - from a few sources I saw, turface was moderate to high CEC and pumice was low to medium. I though clay-based components tended to have the highest CEC.

What keeps you using turface? I've had pretty good luck with it. I tried a few trees with 100% turface last year and they did well. The tropicals seemed to want a little less moisture in winter, which lava helps with. I got nice, fine roots, but some people say turface isn't as porous as lava and pumice, and consequently you don't get as much division in the roots.

What PGRs do you use and what effect do you notice?

 

[Davidlpf]

Most important components for bonsai?

Common sense : Any material won't work properly if you don't know how to use it.

Greetings

 

[Schmikah]

I'm not talking about skills etc, but the material components for good growth. For example...

• Inorganic soil: Lava, pumice and turface, which has a balance of drainage and holding moisture. Turface increases CEC. I might try American Bonsai Supply's Mini
• Fertilizer: I use dyna gro foliage pro 2x a week at half strength, and some CRF in the spring. Currently, I use Osmocote Plus, but I might switch to something organic, like Jobes (and while I don't trust Miracle Grow, their newer organic products look decent). Something pelleted so it doesn't clog up my soil.
• Humic Acid: I just started using this, so I haven't seen an effect yet, but my understanding is it can lower the PH making ferts more absorbable and increase CEC helping nutrients hang around longer in the soil, thus requiring less ferts and reducing the salt content, which facilitates water uptake with transpiration and consequently photosynthesis and healthy growth.

I know other people use other additives, such as...

• Chelating agents: I think dyna gro has most micronutrients in sufficient amounts and available forms.
• Micronutrients: As I said above, I think I have most covered. Though I don't think Dyna Gro has boron, which I was just reading about in a plant physiology textbook. I know a lot of people add calcium.
• PGR: I've experimented with this briefly on a few test plants, but not certain of the outcome.
• Mycorrhizae: I tend to think the spores from nature will make their way into bonsai, but I also get the point that they may be less prone to thrive in inorganic soil, if we use chemical ferts, if the soil humidity is less consistent... and if you repot frequently, so I could imagine there could be some benefit to certain plants.
• Bacteria: same as above... I think mycelium and bacteria are reasons to consider not bare-rooting plants, especially once they have an established nebari/root ball. Many of my plants are too young and get bare rooted each repotting.
• PH+/-: as I mentioned in regard to humic acid, making ferts more available allowing you to reduce the quantity you use would seem beneficial to transpiration and photosynthesis, but I haven't gotten into measuring and adjusting my water PH.
• Rain water: I've thought about getting a barrel, but I have limited space. There are benefits like reducing chlorine would could harm your soil ecosystem, but tap water has important nutrients.
• Type of pot: pond basket or bonsai bag for air pruning? Nursery pot because it warms up the roots for faster growth? Unglazed ceramic for water wicking? Plaster/Mica for longevity? Some people swear by the type of pot they use. I have mostly plastic bonsai pots but may try some bonsai bags or pond baskets, especially if I decide to put a plant in the ground and want the pond basket to facilitate digging it up.
• Other?

I know some of you use all the above and others was to keep it simple, but wondering what you think makes the biggest benefit.

my 2 cents. In my experience (which is still limited) a mix of organic/inorganic has worked the best. I started using a mix of organic and inorganic granulated fertilizers this year, as it is the first time I have a tree in an actual bonsai pot (it's still not fully developed but its teetering on the edge of pre-bonsai/bonsai). At the moment, and depending on the tree/size of the pot, I use about 5 or 6 to one organic-to-inorganic ratio. The main reason is I wanted all the benefits of organics but wanted to boost the NPK numbers on the developing trees without putting too much stress on the micro-biome. So for reference that's a 4-4-4 organic and a 12-10-10 inorganic.

Previously I was using a 10-10-10 liquid that worked fine, but the pain of measuring out fert into a 5 gallon bucket every time I wanted to apply was getting old. I still use a low pH fertilizer for some of the acid loving plants but I would like to get humic acid as a replacement.

Just a testament to how much more growth I've gotten after switching: I have a 'grey owl' ERC that I used the liquid fert on for most of last year. It seems to be more than 5 years old and had all mature juniper foliage. I cleaned up all weak/dead growth last year and it produced some new growth but it was pretty slow going. I pulled it from its nursery container last fall, just to check on mycorrhizae and see how root bound it is. It had almost no fugi in the soil that I could see but the soil still looked OK and it wasn't too rootbound so I decided to forgo the repot and give it another year in the larger container. This year I switched to the granule mixture and by the end of March it exploded. The thing is still pushing massive amounts of juvenile growth without any significant work being done to the foliage mass. I pulled it out of the nursery container again in mid July, colonies of mycorrhizae all over the place.

Obviously this is anecdotal but the massive difference from one year to the next without any real difference in care/watering seems to suggest that the reduction in inorganic fertilizer and/or the introduction of organic fertilizers is the culprit.

The same growth explosion also happened to my ficus and schefflera, but there are some other confounding factors so I can't say it was the fert switch that solely responsible.

 

[Trenthany]

Organic fertilizers are shit as far as I am concerned.

Roflmao he ain’t lying/wrong as my grandma used to say!

 

[JonW]

my 2 cents. In my experience (which is still limited) a mix of organic/inorganic has worked the best. I started using a mix of organic and inorganic granulated fertilizers this year, as it is the first time I have a tree in an actual bonsai pot (it's still not fully developed but its teetering on the edge of pre-bonsai/bonsai). At the moment, and depending on the tree/size of the pot, I use about 5 or 6 to one organic-to-inorganic ratio. The main reason is I wanted all the benefits of organics but wanted to boost the NPK numbers on the developing trees without putting too much stress on the micro-biome. So for reference that's a 4-4-4 organic and a 12-10-10 inorganic.

Previously I was using a 10-10-10 liquid that worked fine, but the pain of measuring out fert into a 5 gallon bucket every time I wanted to apply was getting old. I still use a low pH fertilizer for some of the acid loving plants but I would like to get humic acid as a replacement.

Just a testament to how much more growth I've gotten after switching: I have a 'grey owl' ERC that I used the liquid fert on for most of last year. It seems to be more than 5 years old and had all mature juniper foliage. I cleaned up all weak/dead growth last year and it produced some new growth but it was pretty slow going. I pulled it from its nursery container last fall, just to check on mycorrhizae and see how root bound it is. It had almost no fugi in the soil that I could see but the soil still looked OK and it wasn't too rootbound so I decided to forgo the repot and give it another year in the larger container. This year I switched to the granule mixture and by the end of March it exploded. The thing is still pushing massive amounts of juvenile growth without any significant work being done to the foliage mass. I pulled it out of the nursery container again in mid July, colonies of mycorrhizae all over the place.

Obviously this is anecdotal but the massive difference from one year to the next without any real difference in care/watering seems to suggest that the reduction in inorganic fertilizer and/or the introduction of organic fertilizers is the culprit.

The same growth explosion also happened to my ficus and schefflera, but there are some other confounding factors so I can't say it was the fert switch that solely responsible.

That's great! I found I got better growth as I got better with plants and bonsai more specifically. I can't honestly put my finger on what causes it, but I thought this thread might help move from single anecdotes to seeing what works for a number of people. Another example - I used to kill orchids and now we (my wife keeps buying them) have probably a dozen that are almost always in bloom, and I have no idea what I'm doing differently.

More recently than just getting more vigorous growth, I've found I've been getting a bit better at more compact growth in terms of shorter internodes and smaller leaves. As referenced above, I think part of this is timing of work / pruning, as well as the fact my plants are 1 more year developed than last. Specifically on my schefflera and ficus microcarpa 'kinmen / tiger bark,' the internodes are way shorter than I've had them previous years. I may not even have trimmings big enough that they'd be worth propagating as cuttings next year, while this spring, I had numerous 12-inch cuttings from the schefflera and 8-inch cuttings from the ficus.

 

[Trenthany]

At my moms house/work she has a bunch of orchids that receive no care except regular waterings with the water we wash canoes with. It’s drawn straight from the river with lots of tannins and ultrafine organics suspended. I can’t wait to finish this house so she can retire here and I can get my bonsai there for the water! Between water and light to moderate fertilizing I think my biggest problem will be pruning and I’ll be able to take my trees from 30-40% bark to 10-20% or less I’m hoping. Plus living at work will allow me to water more often during the day instead of only in the morning and evening. I’ve had days where I come home after watering that morning on a hot windy day to dry soil which is terrifying! This is in FL by the way. So in my opinion there is no priority, just a list of best practices and paying attention to what you’re lacking. If your water is very alkaline then pay attention to PH, if your organics plug your soil switch to in organic or liquid organic. Etc. etc. etc. watch what works! The only thing I’m still trying to perfect propagation wise is cuttings. I can’t find the knack for a lot of the tougher trees. Hibiscus I can grow like weeds. So if anyone wants some of my hibiscus (I’ll take pics once they bloom, they were ripped apart and chopped way back after removal from nursery can) I’ll be happy to send rooted cuttings! Lmao

 

[0soyoung]

Interesting - from a few sources I saw, turface was moderate to high CEC and pumice was low to medium. I though clay-based components tended to have the highest CEC.

What keeps you using turface? I've had pretty good luck with it. I tried a few trees with 100% turface last year and they did well. The tropicals seemed to want a little less moisture in winter, which lava helps with. I got nice, fine roots, but some people say turface isn't as porous as lava and pumice, and consequently you don't get as much division in the roots.

What PGRs do you use and what effect do you notice?

I see articles that describe CEC=35 to be 'high CEC'. Regardless, in bonsai I fertilize continuously (more or less), so CEC really isn't a concern like it is in agricultural farming.

Turface is inexpensive and readily available locally. It produces very nice root ramification. It is heavier than water whereas most orgainic bits that accumulate in it float which makes it easy to clean by tossing it into a bucket of water, rinse and repeat, until clear, let dry and reuse. I've considered switching to using pumice with some pines and junipers but hort pumice not as easily available and is much more expensive, so I just haven't tried it. Had it been practical, I would have used in experiments that I was doing years ago on repotting in Aug/Sep versus 'as buds swell'. On the other hand, I have pines and junipers doing just fine, so I think the moral of the story is that I've decided to work on 'the art of watering' instead.

Root ramification occurs for lots of reasons, but an important one is that when the growing tip is deflected by a hard particle, it will branch from the outside of the bend. My conclusion from reading this paper, "Root System Architecture from Coupling Cell Shape to Auxin Transport", is that one shouldn't want roots growing straight through soft stuff like Akadama if they want root ramification. Growing through a hard particle of lava might be different, but I see nothing desirable about having my tree's roots embedded in particles of lava or bark, for that matter.

I fiddle with IBA, Ethephon, BA/BAP, GA3 and Cytocel.