Desert Soil for Phoenix, AZ it's 100 f - 38 c

[Taka]

Hi, This is NOT a "soil wars" thread. I have 13 starter trees in pots. Some of the pots have only inorganic soil. Some of the pots have 50% pine bark and 50% Diatomaceous earth. The trees are 4 inches, 10 cm to 8 in, 20 cm. The Mesquite are seedlings some have Cotyledons and a few are bipinnately compound leaves.
Soil items on hand: Diatomaceous Earth, Red Lava Rock, Decomposed Granite, Small Pebbles, and potting soil.
It's going to be 100 F, 38 C for Aug. and most of Sept. My little trees get morning sun then the patio roof shades them till the next day. A few of my previous little trees have gone to Bonsai heaven, broiled I believe.
Your advice about keeping my trees alive here in the desert will be great.

First the trees:
Ironwood
Chinese Elm
Texas Ebony
Catawba Crepe Myrtle
Dwarf Nana Pomegranate
Pink Melaleuca
Blue Palo Verde
Mesquite
Norfolk Island Pine
Australian Brush Cherry
Hibiscus
Arbequina Olive
Japanese Dwarf Juniper

Yes, I trust the Phoenix Bonsai Club to know what to do.
Yes, the knowledge of Bonsai on this forum is legendary and most helpful.

Now the advice from Phoenix Bonsai Club:

Two basic soil mixes for the Phoenix area
½ decomposed granite (1/4 minus) or chicken / poultry grit + ½ general purpose potting soil mix.
For conifers, use more granite.

Four parts chicken grit + four parts forest mulch + one part peat moss. For acid-loving plants, switch the last two ingredients to one part mulch + four parts peat moss.

“Cactus mix” might be too fine; pure perlite or even crushed pumice is better. Orchid bark is a recommended source for organic material in a mix. Less organic material in the mix is better here (down to even only 5 – 10%). You DO have to relearn to water with that low percentage of organic material — you’ll probably be watering your healthy trees more often. (Added 07/05/04)

Thanks for your advice,
Taka

 

[Anthony]

Interesting ------- the first is 50 % inorganic at 5 mm to 50 % general purpose potting mix ---------- by volume ?

[2] 4 inorganic [ 5 mm ? ] to 4 organic to 1 other organic ---------- by volume ?

for acid lovers - 4 inorganic [ 5 mm ? ] to 1 organic to 4 other organic ----------- by volume ?

Peat Moss holds 15 times it's weight in water.
If Forest Mulch is compost then it holds 20 times it's weight in water

So you have a high water reserve soil ?

Essentially you are using a similar mix to us, but we use less organic material , but maybe the same size
inorganic.

As usual test on expendables ------ cuttings usually.

All you can do is try.
Best of growing.
Anthony

 

[Bonsai Nut]

For what it's worth, decomposed granite IS poultry grit. If you go to a structural / building center for your bonsai soil components, turkey grit is known as #4 granite. chicken grit is #3 granite. I recently contacted a poultry grit supplier about this exact question about a month ago.

The Phoenix Bonsai Club rocks... but there are always soil options out there and everyone has an opinion. I like granite, and use it, but it is non-permeable and won't absorb water, unlike lava or pumice. I would think that in Phoenix that you would want to steer towards permeable non-organic soil mixes, but I don't live there

As far as "potting soil mix" goes, I'm not a fan. It is too easy to compact and clog your soil. If you go with organics in your soil, try to make them chunky like pine bark mini-nuggets, orchid bark (small), rough cut peat moss, etc. Part of the function of a good soil mix is to allow oxygen into the roots. You don't want any soil mix that might compact and suffocate the roots - particularly in a container plant where the sides and the bottom of the pot are already enclosed. That's where having a permeable non-organic base comes in. Even if it is 100 degrees, a trees roots won't dry out if the non-organic mix is holding water like a sponge.

Let me also add... for smaller trees in smaller pots, you want to maintain the same mix, but go with smaller particle size. When I sieve my pumice, I toss the fines and the dust, save the small pieces, and use the medium and large pieces for my standard mix. If I am potting up seedlings, cuttings, etc, I will go to my small pumice.

 

[Anthony]

@Bonsai Nut ,

interesting that you recommend a non organic mix, and the Phoenix Club recommendation is a water retentive mix ?
Why ?
Just curious ----------- no soil war intended -- pax.

Granite on our side comes from Canada, but we don't use it, as it negatively affects the tamarind [ acid preference ]
Suspect there maybe Sodium and Potassium decaying out of the artificially decayed rock.
Did a read up on Wikipedia, seems the granite has clay as well in it.
Now where is Scott ?

We never go past 40 -45 % humidity, heavy clay soils and nearness to the ocean.
So our organic maxes out 1/3 by volume.
Good Day
Anthony

 

[Anthony]

Oh did catch your bit on the chunky, save that those organics will compost and compact as
well. Did some checking with a New Jersey grower.
Said that the bark turned to mush in around three months.
Lots of questions apologies.
Anthony

 

[Anthony]

@Bonsai Nut ,

I figured it out, no need to respond,

Essentially to fit into the Ball Bearing Principle ------ freely draining / 02 and if the balls are
hydroponic clay pebbles ------- water retentive.

What you guys have is a Larger Particle Loam.

Loam = fine sand, decayed stone and clay with some organic matter---------- all fine particles not too good for Bonsai soil.

Loam at 5 mm = silica based gravel [ large sand ] - granite or other ------- akadama /oil seed meal

We used ------------- silica based gravel 5 mm and aged compost with crushed red earthenware brick [ 5 mm ]
as the second water holding material.

Now we have 8 mm water absorbing earthenware spheres and aged compost. Which is out performing our earlier soil
mix.

So if one were to attempt a change on the Phoenix Club soil, it would be an inorganic that absorbs water [ say red lava ]
and could replace parts of both an inorganic and potting soil / forest compost ?
Fascinating !!
Good Day
Anthony

 

[Bonsai Nut]

@Bonsai Nut
Now we have 8 mm water absorbing earthenware spheres and aged compost. Which is out performing our earlier soil mix.

I am specifically responding to conditions in Phoenix, since they are similar to where I live. Because of the heat and low humidity, we tend to water frequently and the ability of the soil to absorb water without clogging and becoming swampy is critical.

One of the problems with using "potting mix", as you pointed out, is that no one knows exactly what is in it My potting mix may be very different than yours. Potting mix differs from brand to brand, and from store to store. Here in Southern California "potting mix" can mean a lot of different things - but it typically means dark 100% organic soil with small particle size that compacts easily. I don't want it in my bonsai pots.

I don't have trouble with bark decomposing as quickly as other places, apparently. Pine bark for me lasts about 3 years. Rough cut peat lasts about a year or maybe two before it breaks down. So I use a similar type of soil to yours - water absorbing inorganic mix (lava and pumice) with chunky organic (small bark and rough peat). My mix is 80% inorganic and 20% organic for most trees. I might go higher on the peat for acid-loving plants like azaleas, camellias, and maples. The peat is important due to our crappy water.

The big question for me is what is the difference between pumice and similar-sized acadama? I have used acadama in the past, and stopped using it because it costs about 4x as much as pumice and I couldn't tell a difference in performance.

 

[Anthony]

Thanks for the reply @Bonsai Nut ,

I may accidentally insult your intelligence, with this response, but here goes,

when compost ages for us, it glues itself together to form a rounded and similar sized
material [ humus ? ] to the 5 mm silica based gravel we use.
This happens after a year of use. So it can't clog anything.

Peat moss first goes to fines in about 6 months, and the later composts and does the same
as mentioned above on compost.
So there is no chance of clogging.
But since compost making takes place above the soil's surface, we only use peatmoss on
azaleas, as when organics compost they first slime and it is uncertain what that does
to roots, since they may not be adapted to that stage of compost making.

Have observed the slime process on oil seed meal , tested on J.B.pine soil.
It will later break up or dissolve when the rains hit it.
Isn't Bonsai soil fascinating?
Good Day
Anthony

 

[Taka]

Anthony, I always get something from your observations and I'm always very interested in your questions. You approach this from a practical, scientific and zen-like (pulling weeds) perspective. Your appreciation for the land and living things is what my Grandfather (Pop) called Maké Washté (Lakota and prounounced Mak-kay Wash-tay the literal translation is "Earth/Soil Good," he'd say that it means, "this is good soil to grow things." I do not have enough Lakota blood to be considered Native American but he was very proud of his heritage and I of him.)

Admin: you always come through. Your response to the conditions here in Phoenix is spot on. I will forgo the "potting soil" and put together some soil that has some chunky organic but mostly inorganic. I'd not thought about particle size so I will also follow through on that advice, good stuff.

Thank you both for responding. This is a great forum and you're really good guys!

PS. right now my objective is to keep my little trees growing. I got that advice firmly stuck in my head from many of the posts.

 

[milehigh_7]

@Taka

I am a huge fan of DE I prefer Optisorb which is about 20-30% bigger than NAPA 8822. On both of those, you MUST sift and get rid of the fines as DE actually holds more water than clay. I don't know what's available in Phoenix but if you can find pumice it is also gold. I think in the heat you are asking for trouble with organics and you won't need them if you use DE.

My mix is based on what's available to me, however, if I could have my ideal mix for the desert it would likely be 30% DE 30% pumice and 30% lava.

Right now I'm about 50% DE and 50% lava. There is a little bit of bark left over in the lava from the cactus mix I get it from but not much. I sift it all pretty well.

 

[Taka]

@milehigh_7
Perfect. Pumice is expensive even on Amazon. DE, Lava, I can do. Will keep checking for cheaper Pumice. My DE pots seem to hold water so that's really good to know.
You're a cool dude Clyde. Thanks much.
Taka

 

[milehigh_7]

You might be able to get it in bulk there bro. @AZbonsai @Ryan H what do you guys do for soil? Perhaps you can all go in together to buy in bulk.

 

[markyscott]

I'm a bit surprised that pumice is not available in Az - you live in a world of it there. Lots of volcanics everywhere you look, in fact.

A quick look on the web suggested it might be available- have you tried this resource?

ACME Sand and Gravel in Tucson:
http://www.acmesand.com/soil-amendments/horticultural-pumice/

The biggest pumice mine in the US outside of California I'm aware of is in Idaho (Hess - http://www.hesspumice.com/pumice-pages/hess-pumice/about-hess-pumice.html) and you can order from them direct by the bag or in bulk. There are a bunch in California- you can buy from them direct also (i.e. General Pumice Products - http://www.generalpumiceproducts.com/horticulture/). Or there are aftermarket folks from whom you can buy in bulk. Jonas at Bonsai Tonight is who I've purchased from before (https://store.bonsaitonight.com/collections/bonsai-soil).

Scott

 

[Bonsai Nut]

ACME Sand and Gravel in Tucson:
http://www.acmesand.com/soil-amendments/horticultural-pumice/

Now we're talking! One ton of pumice for $79!

I used to think a 25 lb bag for $10 was a good deal

 

[milehigh_7]

Now we're talking! One ton of pumice for $79!

I used to think a 25 lb bag for $10 was a good deal

Now holler at those other fellas find someone with a pickup and take a road trip to Tucson!

 

[markyscott]

I noted that they also have 3/16"- black lava cinders for $59/ton - maybe they'll sell you 1/2 ton of each and pour it right in the back of your pickup.

Scott

 

[milehigh_7]

I noted that they also have 3/16"- black lava cinders for $59/ton - maybe they'll sell you 1/2 ton of each and pour it right in the back of your pickup.

Scott

Yep do this and you are pretty much done!

 

[markyscott]

Yep do this and you are pretty much done!

Lol. The way I think I'm preparing to convince my wife that I need a new pickup in order to save money on bonsai soil!

S

 

[Anthony]

@Taka ,

I would love to know from Phoenix members you might visit -

[1] Does anyone use the soil mixes you originally posted ?

[2] How long they have been using it [ anyone with say 30 to 40 years experience ] ?
Any other comments ?

And how you do as time passes on.
Good Day
Anthony

 

[Taka]

@Anthony and @sorce Phoenix Bonsai Club meets again in Sept. My plan is to join and I will ask other long time members about the soil mixes on the website and will let you (and others here on BN) know what the verdict is. Thanks to both of you!
Taka