Before you go crushing up all that lava rock call around to your local feed stores and ask for a product called Dry Stall. It is agricultural grade pumice and comes in 40 lb. bags for about $7 I think. I have been using it for several years here in CA. Feed stores sell it to horse people to spread down in stalls to absorb moisture. The particle size is about 1/8". I wash mine to remove the fines and it works perfectly in my bonsai and succulent soil mix.

Pumice should be easy to find...easier than finding appropriate pine/fir bark fines, anyway....

Of course, you *can* crush large lava rocks....but you'll end up with a lot of dust and waste.

Napa Auto Parts carries a product #8822 (I believe) that is similar to Turface and pumice.

Josh

What's the sudden fixation on 'pumace'? Did someone write a book, was it in a movie, some 'guru' say it was the thing to use?

Bob

Reply to head cutter. I'm no sure how pumice came to be so popular. It is not mentioned in most of the old books on bonsai. In CA the people who collect CA junipers started planting in it because it was reasonable in price and light so a big pot could be handled more easily and it drains really well. Then they started adding it to regular bonsai mix. Recently some of us have started using a completely inorganic mix. Mine is 1/3 pumice, 1/3 scoria and 1/3 Caladama (crushed hardpan). Scoria holds water better than pumice and contains micro-nutrients. Caladama contins micro-nutrients also and is very sharp and seems to promote root developement. I figure that the pumice is mostly a light filler. This mix drains very well but you have to be sure to wash out all the fines before potting in it. You also have to fertilize at least once a month and I use an organic fertilizer so organic material is gradually added back into the soil mix. Soil mixes with a lot of organic material break down quickly and you have to repot frequently (every 2 years or so). With an inorganic mix you may have to repot every 5-7 years.

I just didn't understand why it's become so popular or seems used so much. Amazing...I'd kill for a few bags of decent pine bark mulch...you guys are up to your eyeballs in it and going to using inorganic material. Go figure.

Bob

There is great advantage in having on hand and using at least 2 inorganic soil ingredients with different physical characteristics. Trying to keep the particle size around 1/8" ensures maximum water retention with no perched water. Using an inorganic material that has great internal porosity, and thus good water retention, in combination with an inorganic material with no internal porosity allows you to adjust the soils water retention. Using a soil of primarily organic ingredients, even those slow to break down, like pine bark, can present lots of problems as particle size breaks down and perched water becomes difficult to deal with.

I never use a soil with less than a 2/3 inorganic component because they are so structurally unstable and cannot be relied upon to drain properly during periods of prolonged rain or when inadvertently over-watered.

Al

Well, I as well as a number of others, used a mix of Haydite and screened Pine bark as soil mix. The mix was vaired to suit the type of tree, never had a problem with anything and the trees were very healthy. If the pot is good quality (drain holes) and the soil mix is good you can't really 'overwater' anyway. When the pot stops draining well it's time to re-pot the tree.

Doing something the simple way seems to work best for most people anyway.

Bob

That's a lot of 'ifs'. There is really no good reason to include a large organic component in bonsai soils. The greater the volume of inert ingredients, the more structurally stable will be the soil.

While doing something the simple way may indeed work best for most people, there's no way to correlate simple = best for our plants. While it's futile to argue about which specific soil recipe might be best, there is certainly room and rationale to allow us to suggest that having ingredients in the proper size and with physical properties varied enough to allow us to build well-aerated soils with excellent long-term stability that also are adjustable for water retention by the simple +/- of one or two ingredients while still maintaining an organic fraction less than 1/3 of the o/a soil volume is to be preferred to expecting one or two ingredients to meet all our plant's soil needs.

It doesn't get much simpler than equal parts (by volume) of
screened Turface
screened granite or quartzite chips
screened pine or fir bark

or other ingredients in appropriate sizes that allow the same versatility in adjusting water retention.

Al

Actually it does get simpler, 2 'if's' aren't a lot anyway.
1 part Haydite or screened Turface
1 part screened Pine bark
Vary mix according to type of tree: drier for conifers and most Junipers, wetter (more pine bark) for most deceduous trees.

Never knew of anyone having a problem with that mix. A normal tree only had to be re-potted every 3 to 5 years in that mix. More finished trees needed re-potting less often, up to 7 years or when pot drainage became a problem.
As with everything...it's a free country.

Bob

I wonder how much longer we can beat this horse. I use a potting mix that has been described above but I think that the best thing is to get familiar with whatever mix you choose and the trees you plant in it and your experience will allow you to be successful. I became convinced of this when I visited the Penjing Garden at the Beijing Botanic Garden last year and saw that all of their trees were planted in what appeared to be the sandy loam that was the local soil. It looked to me like they just shoveled up what was available and used it. The trees were all healthy and in good condition. I also think that they choose trees that were suited to their soil and climate. The majority were elms then Ficus microcarpa with Ginkgo, Murraya and Crape-Myrtle. There was not one pine and only four junipers in the whole lot of over 200 trees observed. This experience has forced me to look more carefully at my tree selection and I have decided that I can't keep maples where I am. It is too hot and dry and my water is not of good enough quality. However junipers, elms, Crape-Myrtles, Ginkgos, olives and Tamarix do well. So I am in the process of reorganizing my collection of bonsai. I also have a greenhouse where I have Ficus microcarpa and salicifolia as well as a collection of succulents. There is no substitute for patient experience with whatever soil and variety of tree you are attempting to grow.

I don't think anyone is beating a horse at all. As long as we're discussing the mechanics/physics involved in media, there is much to be learned.

I think the belief that "There is no substitute for patient experience with whatever soil and variety of tree you are attempting to grow." probably needs to be reconsidered because it doesn't hold up under examination. Experience means nothing if you do something poorly over and over again. I have helped hundreds (probably thousands) of frustrated container growers improve their growing skills markedly by simply providing them with an understanding of some of the physics involved in soil science and providing a few recipes as starting/reference points so they could build soils more appropriate than those they were growing in.

The soil is the foundation of every (conventional) container planting, and certainly for every bonsai planting. W/o a strong foundation, you'll be fighting the soil for the life of the planting, which makes about as much sense as avoiding discussions about soils in general.

While there is too much room for disagreement about what materials make the best mix, a good part of soil science is clearly defined and not so negotiable. A thorough understanding of those areas that do not change is a positive for every grower, not just to those recently attracted to bonsai.

Al

What is learned is, what works with your trees--in your pots and growing conditions--is best. Like every greenhouse, bench, garden etc. has a 'sweet spot' for certain plants/trees.

"I think the belief that "There is no substitute for patient experience with whatever soil and variety of tree you are attempting to grow." probably needs to be reconsidered because it doesn't hold up under examination."

Examination? Your examination? That is a close minded statement if anyone ever made one. Experience is a teacher, we learn by experience and grow, it doesn't mean you "do the same things poorly over and over".

Example: I moved to Vietnam...there is no 'dirt' in this country, no 'soil' no Pine bark no Orchid 'mix'. My Bonsai are tropicals because there are no other types of trees here. The 'soil' I use is sand mixed with small Basalt rock chips. It's what's available, there is nothing else except the red clay and some 'dirt' from rice growing and you can make bricks out of that stuff when it gets a little dry. Like others here my trees do very well in that but, I'd still love a few bags of Pine bark mulch.

Overwatering? Try 3-4 months of monsoon rains. The mix and pots drain well enough that there is no problem with overwatering. It's because I set it up that way from 'experience'...I learned.

Experience, a very good teacher.

Bob

There is nothing in what I said to indicate a closed mind, but much in what you said to indicate one. Science is science. There is no need to fear a discussion about physics or soil science, about the benefits of keeping your options open instead of trusting in a soil with little adjustability - the discussion cannot harm you. Even if you disagree and feel your soil is perfect, you don't discount the science behind the discussion wholesale, which is clear indication of the closed mind alluded to.

Experience CAN BE a good teacher, but not all learn from experience - especially those that equate repetition with experience. Those who truly have a closed mind and think experience is the only teacher or that experience can somehow trump knowledge obtained outside of experience are doing themselves a disservice and are the ones most in need of enlightenment. Those who regularly reap the harvest of knowledge are far more capable of progressing in life as experience validates what they have learned. Those who press for the acquisition of knowledge and have the experience to validate that knowledge leave those who rely on only experience standing in their slipstream.

Logic dictates that if this statement is true "There is no substitute for patient experience with whatever soil and variety of tree you are attempting to grow" then it must follow that you should be able to grow pines in pistachio pudding if you are patient. Both ideas are equally absurd. There are substitutes for patient experience in all facets of life.

Al

Thank you Al...you took the time to prove my point very well once again. And, I must say, did it much better than I could (or would have taken the time to).
Actually I never said that (not really MY soil) was perfect, it worked very well and was simple. With so many other variables in the sport of Bonsai some things, when kept simple, cut down on frustration.

Bob

I think what I said is clear and makes very good sense. I'm happy to rest my case.

With so many other variables in the sport [sic] of Bonsai some things, when kept simple, cut down on frustration; and some things, when kept simple, add TO frustration. Both are understatements and of no value as an observation.

Al

Let me see if I've got this right. The last several entries in this forum have been between three guys who have experience in growing and training bonsai and as far as I can tell all three are successful at it. Each in their own geographic location has through patient observation and application of science and experience has succeeded. Did we do that out of mindless repetition of the same mistake? Did we do it by ignoring scientific principles? Did we do it by trying to grow redwood trees in oatmeal? (I hope not more than once.) Fellas we all do ok. There might be room for improvement but we know how to do it. We are all doing the same thing more or less. What's to argue about?

Right and one of us is learning all over again. Huge difference in everything between Pa. and Vn.

Bob

Jack - you accuse me of beating a dead horse, then go on to make a logically fallacious statement to which you're only now adding a list of qualifiers in an attempt to make the original fly. It's really not an important issue, but changing things after the fact doesn't make it right in the original. I wasn't talking about what you might think now after the fact, I was talking about what you clearly said to start this conversation.

As I said in the other thread, it's not important, but I just find it incredible that you or anyone thinks there is no room for discussion of known science when it comes to one of the most important things a bonsai practitioner will ever consider - soil.

Al

I think the operative word about beating the horse was 'we' and not accusing you (Al) of beating it. That's ok, you can take the blame and the horse will forgive you. The crux of the biskit here seems to be Jack using the phrase 'patient experience' in a post...that would suggest learning by doing...learning from your mistakes and making changes.

Al seems to think that humans can not learn from experience, ok so how? It comes from a book and the study of physics or not at all? I re-read those posts a few times and it comes out that way, at least to me and yes, English is my mother tongue so I think I understand the meaning of the words he used to discount the part about patient experience.

Al, soil is one important part of the Bonsai sport, a healthy tree and a good quality pot are the others. Yes, you need a good soil mix but, on the other hand, a poor pot can also lead to a sick or dead tree. Just the soil mix is not the end all of it.

We're having a discussion, it's just when someone doesn't agree with you...they're dead wrong. Get a grip...take a breath...

Your turn at the horse...

Bob

Lol. It's amusing to watch you twist and turn my words, and your own, to avoid dealing with anything I said in the original because you can't refute it. No matter.

I have no problem at all with a good argument/discussion. I don't mind being called wrong, and have no problem admitting when/if I'm wrong; but, unlike others near to this discussion, I tend to not operate beyond the limits of my knowledge. When I offer something, I'm pretty sure it will hold up to scientific and logical scrutiny. So, if you wish to call me wrong, I'm naturally going to be very curious to see if you have your ducks in a row .... or if you even have ducks. If I disagree with you, I don't get personal, I just explain why I disagree, but you're the guy who can't handle that. Arguing against the man doesn't gain you traction, but so far, it's your only argument. It's wearying, so I'll move on to something fun while I'm sure you'll have the last word you always demand.

Al

I was beginning to feel bad because I'd upset you (Al) so much and had some time on my hands today anyway (monsoon season)--all you can do is watch your trees get happy because of the rain and watch the pots drain--so I went back to 3 threads and read through the posts.

What I found was...I don't feel bad anymore.

I will agree on one point, you can argue about soil mix with 10 Bonsai people till the water buffalo come home and, in the end, you will have the same 10 people using the same 10 mixes. Each a little different because it works well for them. In my opinion that's because 'experience' has taught them that; in their area, with their conditions, it's the best...for them and their trees.

I do take exception with you offhandedly discounting and treating with great ambiguities in discounting anything I have posted. There is a trait here of missing (or ignoring) most of what I have posted in the past to retort in only ambiguous cross posts then accuse me of character assination while waving a dubious banner of 'science'. The broad brush of blame while saying nothing in response but blame.

Two of us have been accused of 'twisting' our/your words. In re-reading the old posts (in my mind) we were trying to clarify a previous statement, add some reason/background/facts/truth to what we said. Guess that's not good enough.

Bob

As I said - I'll move on to something fun & hopefully helpful.

Al

I am looking for pumice or pumice substitutes but not for bonsai. As I have had no luck finding pumice I am following the suggestion of several people to try bonsai enthusiasts. My interest has to do with a somewhat particular lithophyte. Plants are impossible to come by in Canada so I am trying some seeds, which are pricey and hard to get, so I don't have the opportunity to experiment. So I appreciate all your comments. Joe

What are you trying to achieve? Haydite has physical properties quite similar to pumice. It would be helpful if you mentioned what important physical properties you're trying to build into the soil, and what size range (particulate size) you're looking for.

Al

thanks Al. The plant is a tropical bulb Worsleya procera. Pumice is recommended as a growing medium for it (instead of soil) by many succesful growers. It seems that the qualities desired are stability, porosity, and ability to retain some water (i.e. not really becoming dry) while ensuring that the roots don't sit in water. Sizes used are described as medium, or 5-10 mm.

I hope the bonsai-ists will forgive me for intruding on their forum!

Joe

You're in the right place. Does your soil recipe suggest an organic component?

Al

Hi Al. No. There is one site that I have found where the author says he grows Worsleya procera in soil, but everyone else says that is a recipe for disaster. Some people have some peat for water retention, but most suggest just pumice. Water retention will not be a problem here in Montreal anyways because it does not get bakingly hot here.

Joe

You're in Canada, so that probably messes up everything I'm going to say, because the products might not be available, or might be sold under different names. You may need to try to get in touch with someone from your nearest bonsai club & find out if they are familiar with the products I'll describe. I've used that approach dozens of times (bonsai contacts) when trying to find a suitable soil ingredient or substitute in any given area.

Haydite (it's like little pieces of brick)is a suitable substitute for pumice, size for size. The problem you may encounter is in the fact that Haydite holds little water. If it IS an issue, you can look for a product like Turface (calcined clay) or floor-dry/oil-dry products made of calcined diatomaceous earth. These products hold lots of water, so you can mix them with the Haydite, or the Haydite with the other ingredient you find, until you find the water retention you need.

The most desirable particle size will be around 2.5-4.5 mm. If the Haydite or pumice is a little larger than that, it's ok because the issue will be water retention & you can adjust that with the other, smaller and more porous product.

If you find these products, you really should come back and talk about your nutritional supplementation program.

Al

Ah, pumice! Delightful stuff, it is! Internal porosity (for moisture retention), structural stability, and a keen aesthetic...that's why I like it. Of course, this has been covered thoroughly in the previous postings.

When I mix "white soils," which have a larger volume of Perlite and Quartz gravel, I like to use light grey colored Pumice.

When I mix "brown soils," which have a larger volume of Bark, I prefer to use the dark red/sienna Pumice, as it matches the overall tone.

The only caveat I wish to re-iterate is this: Pumice holds significantly more moisture than one might think!

Josh

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Ok I have read all the fights out here (discussions I am sure ) so back to basics. I am about to bonsai a King Sago Palm & I have found many believe in the no soil aproach. I think this is what I want & I can see that many different mixs are used in Bonsai but I never read anything about what to feed them or how/often. I know this is an art but when no one will give a hint on enought of this to get started then what do us beginners do? I can buy a book but why when so many out here are probbably just as knowledgeable. Anyone wish to help me out? I am going to start with Heydite, Pearlite, #12 Sand. Thank you.

Ghost59,

Try Dyna-Gro Foliage Pro 9-3-6. I got mine on Amazon after not finding it at my local Home Depot. Tapla often suggests it in the Containers forum. I use the suggested proportions of 1/4 tsp of the Foliage Pro liquid per gallon of water, each time I water (about once a week).

Thank you Pixel Pepper