Akadama, particularly when mixed with other media, is a great medium for growing bonsai (see “All about akadama” for details).
Over the course of the last year, akadama has become harder to come by for several reasons:
- Global demand has increased.
- Mining slowed down due to heavier than normal rainfall.
- Shipping congestion has delayed shipments.
As a result, it might be the case that not everyone looking for akadama will be able to find it. What are our options when availability is limited?
- When possible, postpone repotting. If I’m on the fence about repotting a tree and I don’t have the soil for it, I might wait another year. Although this isn’t an option when water fails to drain at a reasonable rate, it is an option when the primary reason for repotting is to change the pot or planting angle.
- Avoid using akadama for young trees. I have yet to find that akadama performs better for young trees so I no longer use it even when it is available.
- Re-use bonsai soil. If you don’t have problems with pests or pathogens in the soil, you can save akadama-based soils, dry them over summer, re-sift them to remove the dust, and then combine them with other ingredients to create mixes that meet your development goals.
- Use alternative soil mixes. A variety of mixes can serve as good replacements for akadama depending on the development goals.
Young trees can grow well in a variety of mixes. I use 100% perlite or 100% scoria (lava rock) for most of my pre-bonsai. I’ve also used mixes that are 60-80% pumice with the remainder an organic-rich mulch or bark.
Recently collected trees or trees dug from nearby gardens can go into 100% pumice for one or more years while the initial container roots get established.
For mature bonsai, I’d try a few mixes and see which work best for each species based on my growing conditions. I’d experiment with pumice, scoria, decomposed granite, and possibly organic ingredients like bark or mulch.
I’m curious how pines will do with 50% pumice mixed with 50% scoria. Pine growers in Shikoku, Japan, use 100% “sand” that resembles decomposed granite so I’d try using mixes that incorporate that too.
Chojubai growing in 100% scoria
I typically carry akadama-based soils on the Bonsai Tonight Online Store but have been out of stock for some time. I’m expecting more soil to arrive next year between February and April, but I won’t know when until closer to the arrival date. I’ll be sure to post updates when I know more about the timing.
Have your own strategies for getting by without akadama? Feel free to share them in the comments below.
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Great article, as always. On the re-use option, soil solarization (placing the substrate on a tarp, covered by plastic to heat in the sun) might be a great option to destroy pests or pathogens.
I heat treat in South by using the black preform concrete tub covered in plastic. 7 days of sun and done.
steve perea says
I have pines that do very well in straight Napa floor dry, I have mixes putting in scoria, pine bark and pumice, DE seems to work like Akadama. So far here in the PNW it all seems to be very happy, had some sand/compost mix used for landscape and my Italian Stone Pines just loved it, even some of the JBP, they all seem to love sand if it drains well and you keep them hydrated in summer.
Well close to 300 trees now, can’t wait for spring, my local black lava rock supplier is running low, hope they can find more.
Another vote here for DE as a substitute. I use it in various ratios with pumice and lava. Most of my trees are younger or collected and only recently placed in a bonsai pot. So about 5 years in DE at the most. I’ve used it with all sorts of deciduous and coniferous species. I’m also in the PNW. The main drawback I’ve had is the lack of different particle sizes. I find the NAPA Floor Dry tends toward too small, resulting in a lot of waste after sifting. The AXIS landscaping DE comes with fewer fines and a slightly larger particle size.
I recycle my soil as well by placing it in full sun on a black tarp sloping south, drying out completely, then sifting to obtain various grades. This year I’ll add see through plastic on top, to hopefully create higher yet temperature inside of such “sandwich”, which supposedly will kill all bugs and what nots. Of course, lots of sifting is required in this process.
Mert Çiftdemir says
Great post Jonas.
I have 2 questions. You’ve said that “avoid using akadama for young trees”, so what do you recommend for them? Second, what do you think about adding zeolite to soil mixes for deciduous trees?
Yves Rondeau says
Others options :
Sterilized at 200C of volcanic origin, Chabasai has the advantage of not swelling or disintegrating despite watering and the temperature variations;
C.E.C. of 220 meg / 100 gr. The Chabasai is one of the products with the C.E.C. the highest, making it a premium product;
The Chabasai offers water retention of over 40-42% of its weight. Its microporosity helps store water and nutrients inside the cells while allowing air to circulate freely between the grains. So the product offers a unique drainage / retention ratio;
The buffering effect of Chabasai maintains its neutral pH (7.0 to 7.2);
Particle size varying from 2 to 5 mm;
Chabasai is a natural, solid and permanent product which has qualities superior to other benchmark products.
Expanded clay “Expanded Shale”, a sedimentary rock which has been heated in an oven to 2000oF;
Sterile, natural and non-toxic;
Does not swell or disintegrate, increases porosity and aeration, which allows oxygenation of the roots;
Its grain size is between 2 and 5 mm, which allows excellent drainage;
Water retention between 22 and 23% of its weight;
C.E.C. of 18 meg / 100 gr;
Its pH is neutral (6.8 to 7.0);
Its sharp, sharp edges help in root division.
Fábio Antakly says
I believe Chabasai is Zeolite.
Kyle Purvis says
Great post Jonas as usual! I have been experimenting with using expanded shale as an akadama with positive results! I use it due to the high humidity and wet summer in the south east and it has my trees thriving as well as has reduced issues due to excess water. Product is sold under the names stalite Permatill and Episome soil perfected, while heavier than akadama, seems to perform well!
It seems like it’s available if you’re willing to pay through the teeth for it (Amazon). I purchased some a few months back at around $45 per bag, I see now it’s hovering around $70 per bag. The kind I received was pinker than any I’ve ever used before, which is actually nice and pretty.
It’s crazy how the stuff only comes from one country. Kanuma can also be hard to find. I’m unable to find any large granule kanuma at the moment. Pumice and lava rock, at least you have alternatives. Kiryusuna looks a lot prettier than black lava though, and anyone who has used both hyuga pumice and USA produced (bright) white pumice will surely have a string preference. I dislike the white pumice that is still in some of my trees, it just doesn’t look as pretty.
I have used the Napa Diatomaceaous Earth labeled as floor dry. I use It I place of akadama. The only problem is that it is like the small sized akadama. No medium or large grains. Very good substitute for akadama. Especially for younger trees. I use it 50/50 with pumice for deciduous. Or in boon mix proportions..1/1/1. Greats results so far. But finished trees still use akadama when I can get it.
Terence Krista says
Thank you for your article. I’m no bonsai soil expert but I am sort of perplexed at the fetishising of akadama. Number one, it is very expensive and the carbon footprint dragging it over to the US is not small. Can’t we come up with something as good but more locally produced? I’ve been doing bonsai for 25 years and have always used a mixture of 2/3 agricultural pumice/scoria and 1/3 sifted fir bark fir both beginning and more developed trees. In the Bay Area where we often have no rain between March and November (unlike Japan where there is year round rainfall) I find the fir bark helps greatly with moisture retention. Pumice, scoria and fir bark are available locally and at a fraction of the cost of imported Japanese soils. My two cents.
Joel Cervera says
I’ve been using diatomaceaous earth. It’s labeled as floor dry from Napa. Just like the poster above. I’m in north SF Bay. I use it in place of akadama in my mixes for young trees and trees in development. Trees closer to finished get akadama. It has some similar properties to akadama in inretention and CEC. 50/50 with pumice for deciduous. 70/30 for conifer. Or 1/1/1 with scoria and pumice for a boon type mix. Great results so far. Cheap and available. Main drawback is small size of grain. O medium or large grain available. Also wear a dust mask when sifting! DE dust not good for your lungs
Don Pettit says
Great article Jonas. As a community, we need to find US alternatives to Akadama, as the cost to the planet is too great a burden to continue that practice indefinitely. From the shipping to the loss of soils in Japan, there has to be a better way. Some in Oregon are finding soils suitable for use as Akadama replacements. But we need to find better sources of durable volcanic clays, use and test them for applicability, and share that knowledge with the community. We have a similar geologic setting and no shortage of volcanic products…even though our climate is a bit different. Please scout suitable soils and use them in your bonsai. We can do this!
As stated above , I too have used DE Napa floor dry. Again, it’s small but I also feel there are other drawbacks. I think it retains more water than I like and it also does eventually break down. I have sourced a large quantity of pumice for
Myself to collect yamadori this spring. Maybe I should try to sell some of it to those in need.
Daniel Lepage says
I use the same mixture as Yves Rondeau Chabasai-Haydite and I add composted pine bark and a little Charcoal. The mixture is very stable over time with the gel. The price is also very affordable.