I have long been on a quest for the perfect bonsai soil. Many bonsai folks claim to have found
this and will gladly sell you some for a premium price. Some will give you their magical secret recipe sometimes even for
free. The problem is finding the same ingredients in different locations and having them readily available and at a reasonable
cost can be tricky at best.
My bonsai soil concoctions came after much searching through books
as well as the internet, and much frustration. When I found the article that finally turned my research into practice - I
can’t remember the location or the source now but it was a well written article that I enjoyed reading it. The point
of the article was that all of the debate, secrets and high prices mixing around about bonsai soil are nonsense,
just get the three key elements:
(1) Drainage keeps the roots from standing in water or soggy
wet soil both of which will cause health problems including root rot and the eventual (depending on the species sometimes
very quick) death of the bonsai.
(2) Water retention. The absorbency of the soil which keeps
it from drying out too quickly and also gives it the ability to hold nutrients and minerals.
Air capacity. Roots absorb oxygen from the air found in pore spaces between soil particles. So the particles used for the
drainage or the water retention or both must have the ability to breath.
Many books show perfect bonsai soil of some strange material in the photos and then tell you
to use grit and organic soil varying the amount of organic soil dependent upon the plant and how free draining it needs to
At this point I tried many different grits from coarse sand to tiny sand blasting gravel and
added peat moss for water retention. This worked out as a good method but I still killed the occasional bonsai tree from too
much of one or the other ingredient for the particular tree variety. I’ve lost some pretty amazing trees over the years
and it’s always painful. The other problem was that the peat would break down rapidly and compromise the condition of
the soil forcing me to repot often.
I once went to a bonsai nursery where every tree the owner had (and there were a lot of them)
were planted in red lava rock. The concept of using one single ingredient was new to me and I liked it. The problem was, the
nursery was far from home and I never was able to source the tiny grained pumice like open pored lava rock. For a while I
was purchasing the common landscape red lava rock and screening it for the small desirable grains. This turned out to be a
lot of work and it still dried out faster than I liked in hot weather. I tried using coarse perilite but didn’t like
the starch white artificial look whether it was wet or dry old or new.
In the end I ended up
settling with screened red lava rock mixed with small amounts of organic soil to amend it.
used this recipe for several years until I decided to pay a visit to one of my favorite bonsai sites and see what Harry Harrington
of "Bonsai 4 Me" was using for his soil.
I found this page AN INTRODUCTION TO BONSAI SOIL and read through it particularly interested
in his talk about inorganic soils. This is when I learned that the strange miracle stuff my imported Satsuki Azalea bonsai
tree had been happily growing in for the past 4 years was Akadama. And soon after this I ended up on Harry's “Kittydama”
(his joke derived from Akadama) page where he is taking the time to give this super bonsai soil it’s world
wide availability variations!
I read down and found the USA version and minutes later I was standing
in Napa Auto Parts excitedly asking for a bag of their Super Absorbent. (Which by the way they have two kinds of. One being
made of corn cobs and then the other the amazing diatomaceous earth variety.)
I potted several
species of bonsai in it and have at this point (6-7 moths later and well into the growing season) had perfect success!
You just have to be certain to fertilize right off the start because inorganic soils do not have the necessary nutrients like organic soils do.
I have since found the exact same product in a different package at Walmart for about 60% le$$ (in my location) sold
as “Special Kitty Cat Litter”.
This diatomaceous earth Kitty litter or “kittydama” has all of the elements of an excellent
bonsai soil. It warns you when it’s drying out by turning white, it looks great when it’s damp, it has pest fighting
capabilities and insulating value which perhaps could even help protect the shallow roots of your favorite bonsai tee.
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