Potting Mixes Presentation
     At California Bonsai Meeting
By Gary L Castagnola
January 6, 2004
     Revised 3-2-05
Resources
John Naka Manny Martinez De-ionized water source:
Marybel Balendock Pacific Industrial Water
Cheryl Manning PO Box 3039
Ernie Kuo Fullerton, CA
800-720-7080
Roy Nagatoshi  714-680-8800
Fuji Bonsai Nursery
13170 Glenoaks Bl "Miniatures Bonsai"
Sylmar, CA Herb L Gustafson
818-367-5372 Sterling Publishing Co.
     Source for red volcanic rock
Yamada Co (nursery supply)
706 W Gardena Blvd.
House of Bonsai  (Victoria) Gardena, CA
5214 Palo Verde Ave 310-327-5668
Lakewood, CA 90713
562-804-6481 A - 1 Grit
     Prescreened decomposed granite, 909-792-5681 (San Bernardino area)
    Korean granite, Akadama, Red Lava rock, Source for turkey grit; call for directions
    Pumice, Hyuga, sand, premixed blends
New England Bonsai
Lindsay Shiba 914 S Main St (Rt 126)
Mt Fuji Garden Center Bellingham, MA 02019
1555 W. Foothill Blvd. 508-883-2842
Upland, CA 91786
909-985-2219 Chikugo-En Bonsai Nursery
     Source for red & black volcanic rock 18110 S Western Ave
Gardena, CA 90248
American Horse Products 310-3232-4011
27959 Cabot Rd Masaru Ishii
Laguna Niguel, CA 92677, tel 800-500-0799 Gary Ishii
Dry Stall (small grit pumice)
UAP West
1011 E Third St
Kruse Feed & Supply Corona, CA
1459 Santa Anita Ave. 800-777-4388
So. El Monte, CA 91733, tel 626-575-6000 Source for "AXIS" regular grit size for potting mix
     Dry Stall (small grit pumice)
Gail Material
DiMario's Builder's Supply 1256 Magnolia Ave
8020 Phlox Corona, CA (adjacent to Magnolia & I-15 exit)
Downey, CA 909-279-1095
Builders Material Brick & Block Yards Source for Turfas potting mix (NVP grit size)
     Source for # 12 grit river sand
Interviews
Roy Nagatoshi, Fuji Bonsai Nursery,
About 16 years ago, Roy began experimenting with red volcanic cinder rock.  Over time
he has come to use the red rock almost exclusively for all bonsai potting, except
azaleas and other similar plants.  Why cinder?  It is a hard mineral material that doesn't
break down.  When first used it is found to be high in sodium, but that washes out
over time.  So, it is very important to wash it thoroughly before placing it in your potting
mix.  Testing the rock in actual pots, Roy determined it tends to hold heat longer,
thereby helping in promoting root growth.  The time frame for roots to grow is expanded
and the extent of growth within the pot is more efficient, rooting throughout, not
just at the edges of the container.  Cinder rock is lighter than decomposed granite,
easier to wash than D.G.  Roy never mixes cinder with D.G, just with other organic
materials.  Available in either red or black (grey), choice is a matter of  personal
preference.
 
Ingredient mix ratios:
Standard mix for pines, junipers, similar trees
70% to 80% cinder rock with the balance of organic potting mix (bagged,
typical prepackaged available in nurseries, including peat moss, redwood soil
conditioner, etc.) 
Deciduous trees… reduce cinder to 60% to 70% with balance in organic
prepackaged mix. 
Word of caution, he has found that it is best to not use less than 60%
cinder rock. 
Other thoughts:
I questioned Roy about the use of decomposing redwood, soil builder. 
Some have said it robs the soil of nitrogen, or that it is not good for
flowering or fruiting trees.  Apparently, when mixed with cinders, he  has
not encountered any problems.
Roy avoids the use of fir bark because he finds over time in the pot, fir bark
gets slimy, not healthy for the tree.
For plants in training containers, 5 gallon cans or larger, etc., Roy uses
a mix of 50-60% sandy loam, with a balance of any organic mix available.
Kellogg Topper Soil amendment is an example.
Akadama?  Kanuma?  With his current mix noted above, Roy has found
no need for either of these imported soils. 
Peat moss… favorite brand is "Sunshine."
Best tip of the day:  Keep your tools clean.  When pruning, he washes
any tools he used on previous trees.  Recommends a 50 - 50 mix of water
and Lysol disinfectant.
Roy does not recycle his mixes.  Trees are watered by hand,  once a day.
Ernie Kuo
Noted for an excellent and varied collection of bonsai, especially California Junipers,
Ernie relies primarily on agricultural pumice that has been thoroughly washed, three
times to be sure it is really clean.  Pumice is used exclusively with the California
Junipers. 
For other trees, which he refers to as being less fussy about their potting mix,
Ernie uses a blend of the following ingredients:
Prepackaged organic potting mix (such as, Home Depot's products)
   none of the organic is screened before use.
Perlite
Vermiculite
Orchid Bark (for good drainage)
Turkey grit crushed granite (similar to # 12 sand)
   used with all of the above to some degree or another
Akadama (with crushed granite for Pines)
Ficus trees are potted with primarily organic materials.  Oaks with primarily
pumice and little organic.  Lantana with pumice and turkey grit.  Bougainvillea
receive mostly pumice.  Hibiscus, maples, elms in mostly pumice but
also more organics than other trees in his collection. 
Water:  once a day during warm weather, during the late afternoon, early
evening.
Other comments:
Ernie's trees are very healthy and obviously well cared.  What is unusual
in this area, inland, warm and hot during the summer, is the extent of lush
moss growth on the soil surface.  While he attributes this to being fortunate
in that moss grows readily in his yard, I suspect it has something to do
with his weekly fertilizing feeding with Miracle Grow.  Recently, he started
using imported fertilizer pellets, with continuing success with moss growth.
The moss is removed from the soil surface once a year and it grows back
vigorously.  De-ionized water is used exclusively on the azaleas and maples.
Tap water on everything else.  Ernie does not recycle his mixes
House of Bonsai, Vickie
Vicki is a very enthusiastic bonsai artist and owner of a commercial nursery
in Lakewood, CA.  This interview was important to me because she has
a variety of tree material that we do not normally see in southern California.
Her basic mixes are different according to both the age of the tree in addition
to the variety of tree. Generally speaking, younger trees, and those that will
be sold to beginning students, are potted with lots of organic material.
Because of their age, older trees are potted in less organics.
Older trees, receive a larger proportion of rock and / or decomposed granite.
Trees planted in nursery cans for general stock are planted in a mix of mostly
compost (80%) and course builders sand, and even normal ground soil.
(Her nursery is located on a old riverbed plane, soil tends to be sandy loam)
For compost and organics, she uses most anything she has on hand.  Cedar
bark is good but difficult to find.  Fir bark - forest humus- shredded
wood shavings are typically used with good results.  One exception
regarding the use of redwood shavings is that she has found redwood to be
toxic to flowering and fruiting trees. Un-screened wood compost is trucked in to
her yard. 
When potting pines, she uses Akadama and includes some of the original soil
from which it being repotted. She may also use an imported product, Korean 
decomposed granite.  It is a harder rock than our local D.G. and does
not easily break down.  In place of Korean rock, she uses red lava cinder
rock.  Generally, then, with pines, she pots with a 50/50 mix of Academa and D.G. or lava.
Vicky also uses the cinder rock and Korean granite for the bottoms of
bonsai pots to promote easier drainage.  Most of her premixed potting products are already
screened.  However, some to the prepackaged commercial bags of humus need prescreening.
Basic mixes can range from equal parts compost (humus), sifted # 12 sand, and
lava rock ( or Korean granite); to a blend of 80% Red lava and 20% Akadama. 
The blends vary with the type of bonsai material, age, and geographic location.
With azaleas and camellias, Kanuma is used with organics.
Like most of the interviews, good soil drainage is emphasized.  Dust and
small grains of soil must be removed.
A word about Hyuga: Apparently, folks in northern California use this material as a key
potting mix ingredient.  It is a hard, rock type substance, and comes in 3 grit sizes.
Orchid growers in southern California use it in their mixes.  As it is somewhat new to
us in this area, it will be interesting to learn of its applications for Bonsai enthusiasts
in southern California.
Frequency of repotting depends upon many variables.  In general, loose
guidelines are as follows:
Repot during the spring after the threat of frost is no longer.
Depending upon your geographical
location and unique micro environment, from late January
to late May.  Non fruiting / flowering trees can be repotted
in the fall (October - November)
Deciduous trees are repotted when the buds begin to swell,
or after the new leaves harden later in the spring.
Olives & bougainvilleas are best potted in mid summer (strip
the leaves).  Flowering / fruiting trees are done just before the
flower opens.
Except for pines and deciduous trees, most everything get
repotted every three to four years. Pines are repotted on
a four to five year schedule, elms and maples every year. 
Flowering bonsai are done every three years (they show best when
root bound).  This is especially the case for wisteria.
Podocarpus are best done in June.
Azaleas, are repotted just prior to the blossom bloom and every
three or so years.  It helps to debud the new flower buds prior to
bloom.  This will push the tree to produce better blossoms the
following year.
John Naka, Marybel Balendock, Cheryl Manning
An interesting interview with three of our top bonsai artists at one time. 
#1 and most important of all… Screen and sift and clean
all of your ingredients before use!
The basic organic ingredient in their mix is a commercial grade bagged
cactus mix.  The brand sold by OSH is currently in favor and also is said to
be used by the L.A. County Arboretum.  Before blending with the other
ingredients, the humus is screened through a 1/4 inch to a window screen
size, reserving the larger particles for the blended mix. Cactus mix
is more porous and faster draining than commercially bagged humus mixes.
Their basic mix ratios are as follows:
60% Akadama to 40% screened OSH humus mix
50% crushed granite to 25% Akadama to 25% OSH mix
Maples receive 50% OSH mix to 50% Akadama
Marybel's famous liquid amber grove was last repotted  1-25-02
in 50% OSH, 25% Akadama, 25% D.G.
Elms get 60% OSH, 25 % lava cinder rock, 15% decomposed
granite
Pines are repotted in a mix of 50 / 50  screened D.G. &  Akadama
Reportedly, some pines do not like red lava rock.
Pomegranates were last repotted May 1, 2002 with 60%
Akadama, 30% OSH, 10% D.G.
An alternative for D.G. is turkey grit
When using Akadama, the frequency of repotting must be
more closely watched as the soil breaks down sooner.
When repotting, remove the bottom first, then about 1/3 to 2/3
of the remaining soil.
Distilled or de-ionized water is used on all trees except for
California Juniper, and elms.
Cheryl has recycled her potting mixes in the past by spreading
the castings onto a warm concrete driveway during the summer.
It is covered with a plastic sheet and "cooked" for several days,
then recaptured for future use.  Some people bake it in an oven for
an hour or so then reuse it.
Marybel said "life's too short to mess with it."
Lindsay Shiba
Another advocate of lava cinder rock, Lindsay uses the black or dark
grey variety.  With the lava he adds L & L Brand cactus mix in various
ratios depending upon the material being repotted.
Pines 1/3 lava cinder rock
2/3  cactus mix (standard prepackaged bagged)
Older pines & Potted in 100% cinder rock
Calif Juniper
Azaleas & Same as above but also add course peat moss
Camellias
Maples 1/2 'n 1/2 cinder to cactus mix
Lindsay has found that lava promotes slower growth and more back budding
than mixes with higher organic blends.  Because summer weather is warmer
than the coastal regions, watering is done twice a day on a drip system. 
Liquid Ambers require shade during hot days to keep the root structure
cool to their liking. 
Fertilizer is applied about every six weeks.  Ammonium Phosphate is used
almost exclusively from February through December. The NPK is 16-20-0
13% sulfur.  It dissolves quickly and the trees are able to absorb it more
efficiently.  Each tree receives about a tablespoon each feeding.
Sometimes he supplements with an organic liquid plant food.
He does not use solid organics like bone, blood, or cotton seed.
When repotting he does use plant vitamin B-1 (1 to 2 teaspoons per gallon)
Frequency of repotting:
Deciduous every 2 -3 years
Evergreens every 5 years
He does not recycle soil mixes.
He does not use copper wire. Copper coated aluminum is okay. 
General purpose nursery canning uses a commercial grade planting mix
in bulk form together with course sand.
 Manny Martinez
Manny is the person who introduced some of the newer potting mix ingredients to me. 
These include Turfas and AXIS, products used by the agricultural and professional
landscape industries.  In addition, I learned about the Magnetizer water conditioner
system from him. More about the Magnetizer a bit laterin the presentation.
For the past six years or so, Manny uses a simple potting mix blend that seems to
work well for all of his collection. He blends equal parts of the hard fired AXIS
and Earth Gro (red label) organic bagged potting soil.  He buys AXIS from UAP in
Corona, CA (see Resources at the beginning of this summary), and Earth Gro
from Home Depot @ $1.99 per 1 c.u. bag.  He does not screen either ingredient.
He completes each potted tree with a blend of equal parts earth worm castings and bone
meal, which is then mixed with some of the soil mix, and then places a thin layer on
the soil surface.  He has noticed that since using this formula over the years,
he seems to encounter fewer insects and greatly improved moss growth.
Looking at his collection, his potting techniques have served his bonsai quite well.
Each tree appears vigorous and healthy. Even though he lives in a hot and dry
summer climate, moss growth is indeed prolific. 
Manny's collection includes deciduous trees such as maples, liquid ambers,
pomegranates, and evergreen tropicals and California juniper.  He does not
grow pine trees.  He waters during the late afternoon, allowing the water flow to
continue until it drains out of the bottom of each pot.
His fertilizer application technique is interesting.  Using a 1/2 inch diameter dowel,
he pokes holes about every 2 inches into the soil mix around the pot.  He then places
Agriform pellets into the holes and them covers them up with soil.  This ensures
full root feeding down to the bottom of the pot, and prevents the fertilizer from washing
away when watering.
Repotting frequency: Only when the roots start to lift the tree out of the pot.
Chikugo-En Bonsai Nursery
Meeting with Gary Ishii, we had an interesting discussion of the potting mixes used
in his family's bonsai nursery.  For bonsai, they use almost exclusively no organic
potting materials. Bonsai receive either Akadama or a blend of both pumice
and Akadama (50-50).
For planting in nursery cans and trainings in larger containers, a blend of top-soil
loam mixed with a packaged red wood soil builder is the medium of choice.
All ingredients are screened before use.  The Akadama is also sorted by size, small
medium, and large.  Depending upon the depth of the pot, the soil is layered into each
pot, largest on the bottom, smallest on top. 
A previous discussion of the issue of sorted or staged layering of potting mixes
indicates that recent studies show this may not be the most efficient way to pot your
trees.  However, Gary presents a compelling argument for layering Akadama and I suspect this
this is an exception to recent thinking about this subject.  Perhaps the porosity
or structure of Akadama prevents some of the problems we encounter when
layering our typical western style mixes.
Generally, Akadama is the mix of first choice.  Conifers are potted exclusively in
it.  Other varieties are potted in it along with screened and cleaned pumice.  Shohin
and accent plants are also potted in the same ingredients. Special care must be 
taken when watering as this mix holds water longer than might be expected.
Gary also stressed the need to be sure to clean the old soil away from the roots located
immediately next to the tree trunk.  Eventually, all of the old soil must be removed and
replaced.
In addition, he pays close attention to the PH level of both the water and soil.  His goal
is to maintain a neutral level of about 7.0.  In this regard, he uses a water treatment
product named HB-101.  He finds it helps maintain this PH level and makes their
water "wetter."  Using a Hozon brand brass hose siphon ( with a ratio of 1:15), he
mixes up a batch of 5 gallons of water to 30 cc HB 101 (equals a 1/10,000 proportion)
Incidentally, the siphon system is quite simple and nifty. It can be used to apply liquid
fertilizers with ease. (1 gal. = 3.17 liters.)
A commercial grade of michrochizza is added when potting up bonsai. 
Other sources: Water test kits, 800-248-8823, Hozan siphon available at Yamada Co.
see Resources section.
New England Bonsai
I first learned about the vastly different new potting mixes during my visit to this
nursery a few years ago.  This sparked my interest in creating this study.
In addition to bonsai, tools, and accessories,  New England Bonsai sells and ships 
soils and soil blended mixes.  The various mixes are uniform in size, thoroughly
screened and course to allow rapid drainage and air circulation.  You can purchase
the ingredients individually to prepare your own blend, or buy prepackaged bags.
There are three basic components mixed in various proportions according to the
need of a specific variety of tree.  These three include a sifted grey stone from Lake
Champlain, Vermont;  course river sand in three grades, #3 the smallest, # 4…
the size recommended for potting mixes, and a larger pea size # 5. 
The third ingredient is a clay particle called Turface.  This calcinated clay
is considered an essential component when mixing your own blends.
Premixed soils are as follows:
Original Blend - the primary mix for most trees.
All - Purpose - double screened, earthy color, general use for small to
medium tree.
Master All Purpose - triple screened, suited to medium to large trees, or
bonsai needing fast drainage.
Master Course Soil - triple screened with larger particles for fastest
drainage.  Good for larger bonsai and conifers.
Shohin Soil - smaller particles, still drains well, also good for tropicals
Tropical Bonsai Blend - contains a greater quantity of bark mulch
to retain moisture.  Good for medium to large size tropicals and sub-
tropicals.
In addition, they sell a hard-fired version of Akadama soil.  The soil particles are
brick red, and because of the hardened texture, it is especially suited for conifers and
for use in wet climates.  It comes in three different sizes.
They also have Kanuma soil, recommended for azaleas.  Their literature does not
describe the blend of materials in azalea mix, but says Kanuma is included along
with other ingredients.
Finally, New England Bonsai sells a Micorrhiza soil booster.  The beneficial fungus
helps plants to utilize nutrients thereby accelerating growth.  The threadlike fungi
attach themselves to the roots and also help to increase water retention.
 Basic Potting Mixes
It helps to know that there are only few types of soil blends that individual kinds of
bonsai require.  Now that we know that less organic material is needed in most of
our mixes, it should be relatively easier to determine what we need to do to modify
the basic blend to accommodate your special tree. Every bonsai enthusiast must,
to varying degrees, learn to adjust their basic mix by trial and error, and asking
others who share our interest.  Therefore, the following is but a relative guide from
which you will tweak to suit your needs and conditions.
  The basic blend.  Decide which course grit,non organic ingredient