Can kanuma soil be mixed with regular potting mix?

I bought kanuma soil and i decided i don't want it to be just kanuma alone, i want some organic matter in there so it will be ok if i water it once a day or even every other day. (this is for an azalea)
So i was wondering should i mix 60% kanuma and 40% lime free potting mix. Or instead of potting mix should i combine the kanuma with sphagum peat moss and some mulch.
I was told to be careful with kanuma soil because it turns into dust or compacted if handled roughly. If there's more i should know i would greatly appreciate it. Thank you =]

hi,
you'll find there are as many soil recipes and advisors as there are varieties of azalia !

I use pure kanuma for my satsuki - it hold loads of water so no need to worry about it drying out - even though at first glance it looks like stones they are actually porous honeycombes. The one reason kanuma is so good is due to a property i have not found in any other soil ingredient - the fine roots penetrate into the grains to use the moisture held within, and can pass right through searching further into every grain of soil.
Other fired soils do not allow this complete penetration, so can actually limit the amount of possible root growth to the spaces between the grains. (my Acers and beeches thrive with kanuma mixed into the soil too - but it holds much too much water for pines).

if you use kanuma you need to feed very well as it has no nutrients the plant can use. Adding the organics you mention would supply some nutrients to the tree, so you could feed a little less, but it would not aid in watering (or lack of) - composts once bone dry are actually much harder to re-wet. If you have very very hot days all soils would dry out, so cover the soil surface in moss or finer soil - this layer will maintain more moisture below.

you will get several alternative answers though, as my observation is that japanese soils dont seem to have that many American advocates on the forum. If you have 2 trees experiment for yourself - one in pure, one in a blend - it takes 2 or 3 years for an azalea to decline so just watch them closely for yellowing leaves and skinny bare branches.

cheers Marcus

katsols wrote:
instead of potting mix should i combine the kanuma with sphagum peat moss and some mulch.
I was told to be careful with kanuma soil because it turns into dust or compacted if handled roughly. If there's more i should know i would greatly appreciate it. Thank you =]

Hello,
Better no garden soil in a bonsai pot, you need a good free drainage.
Your second option looks fine to me, but a local member will be able to tell more on the special percentage of the mix.
One thing about kanuma is that it can fall apart after a frost period and leave you with a failing drainage,
some winter protection is good.
Is it a young azalea and is it in 100% garden soil on the moment?
If this is the case you could change the pot mix over two repots, take care to place the roots from the start in a radial manner.
Sunip ;)

sunip wrote:
Is it a young azalea and is it in 100% garden soil on the moment?
If this is the case you could change the pot mix over two repots, take care to place the roots from the start in a radial manner.
Sunip

It's not too young, it has a nice almost 2 inch trunk i bought it from a nursery so it's in garden soil. My plan was to keep it in a training pot for a year with a bit kanuma soil mixed with regular soil.

marcus watts wrote:
if you use kanuma you need to feed very well as it has no nutrients the plant can use. Adding the organics you mention would supply some nutrients to the tree, so you could feed a little less, but it would not aid in watering (or lack of) - composts once bone dry are actually much harder to re-wet. If you have very very hot days all soils would dry out, so cover the soil surface in moss or finer soil - this layer will maintain more moisture below.

Thanks a lot, it really helps me understand kanuma soil a lot more. =]

Hello,
If you plan to repot now, remove all flower buds.
The tree will have all energy to root again.
Good luck.
Sunip

Well, in Kanuma, we planted satsuki in straight Kanuma soil. Some of the satsuki, especially cascades or semi-cascades, would become potbound very quickly (smaller surface area). When we removed them from the pots the bottom half would be free of any roots, and the granules just as fresh looking as when it went into the pot despite being there for at least 2 years and going through freezing winter temperatures.

We mixed Kanuma soil with akadama and other components for the other bonsai. Oh, and I've never felt compelled to buy and use Kanuma soil, akadama, or anything else from Japan here in the states.

Russell Coker wrote:

Oh, and I've never felt compelled to buy and use Kanuma soil, akadama, or anything else from Japan here in the states.

Really? may i ask why out of curiosity lol.

Because I'm very happy with the results I get with our own soil mix, and I like to spend money on other things!

Russell Coker wrote:

Because I'm very happy with the results I get with our own soil mix, and I like to spend money on other things!

Russell, care to share your recipe? I want to be prepared when I work on my (tiny) azalea. Thanks!

Poink88 wrote:

Russell Coker wrote:

Because I'm very happy with the results I get with our own soil mix, and I like to spend money on other things!

Russell, care to share your recipe? I want to be prepared when I work on my (tiny) azalea. Thanks!

Nothing mysterious here. Just turface, red lava and sifted pine bark. I start with equal parts of each, but may add more bark or even potting soil depending on what I'm potting and how far I need to stretch it. The red lava, or 'flower rock' has become hard to come by in these parts.

The point is that you don't have to use Japanese soil to grow anything here. Don't get me wrong, if I had a cheap source I'd happily add them as components. Now, I think my bank would appreciate me making mortgage payments instead.

Russell Coker wrote:
Nothing mysterious here. Just turface, red lava and sifted pine bark. I start with equal parts of each, but may add more bark or even potting soil depending on what I'm potting and how far I need to stretch it. The red lava, or 'flower rock' has become hard to come by in these parts.

The point is that you don't have to use Japanese soil to grow anything here. Don't get me wrong, if I had a cheap source I'd happily add them as components. Now, I think my bank would appreciate me making mortgage payments instead.

Thanks Russell. I am with you and always looking for the best value.

Russell, I wonder when do you use potting soil/coco peat/peat/sphagnum moss or whatever it is you use and when do you go 100% substrate?

I also wonder a bit about pH. What is you use 100% inert substrate like lava stone, turface or perlite?

I use 1-1-1 peat, perlite, pine bark. I do have a hard time finding coarse peat here, which is desirable. Here in Europe we have black peat and white peat. So far all the stuff I had has been black peat and milled. So I tried some white peat. But it's also milled and it doesn't really look any different.
Also, the pH on the bag is 3.5. I don't know if this is too low.

So now I mix that peat with cocopeat/coir instead. The coir is actually more coarse, though still not ideal and has a pH of 6.

I am also considering using something that's harder and bigger than the perlite I have alongside. My perlite is very dusty and breaks apart easily.


One more thing about pine bark. I have heard some people talk about it acting like a sponge for salts and it itself releasing manganese and/or absorbing nitrogen(causing chlorosis). Apparently pine bark that decomposes too quickly can not be good. And overfertilizing when you have pine bark can be worse than if you had peat?
Now my douglas fir bark is supposed to be perfectly safe because it decomposes safely. Do you have any insight in this Russell?
I saw one person on some other forum that had his azaleas in 50% pine bark and they had both chlorosis and fertilizer burn symptoms on the leaves.

The surface of my soil mix dries out pretty fast. Now the root balls of my plants are still filled with peat as they are nursery plants and not bonsai. So not really sure about how much I should water.
Now all my large azaleas are non-bonsai. I repotted many plants and they are all ok except for 2. I don't really know why this is.
One never came out of dormancy while my other plants of the same cultivar in the same potting mix did. Maybe it was damaged by frost even though I moved them inside for the most intense frost.
Had something similar on a plant last year and that one died.
I suspected that these two plants were underwatered and watered them a lot but it seems that wasn't it.
Now one also had some branches die back, but I think it may have been that that plant was not actually 1 big plant but many cuttings fused together and me raking open the root ball destroyed the root system for some of them.

I hoped to cross with this plant. It would have been my only large white satsuki-type seed parent that is fertile and I got it through a French mail order. I am supposed to become an azalea expert but I have precious plants die on me
Still I have plenty perfectly healthy ones left.

Ok that's all azalea related I have for now.