Azalea propagation substrates

Woodengun

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Hi all! I know Glaucus and Deep Sea Diver are very experienced in this so I’m aiming this question at y’all or anyone else who has satsuki propagation experience.
The past year I’ve been experimenting propagating satsuki varieties via cuttings. After A LOT of failures I have my method down. ( around 80% success ).
After rooting what is the best peat free option to grow the small whip / cutting in for the best success for future development?
I would like to grow 8-12” whips, then wire, then ground grow.

I talked with Jim Nuccio and peat / perlite seems to be the best but I’m really trying not to buy peat for anything anymore…
I have 10 rooted cuttings in pure kanuma, and 10 in a coir, perlite, worm casting mix. ( osakazuki). I just have not had a lot of luck with coir… so I’m wondering if there’s anything else to try? Kanuma is pricey and I’m reserving that for my mature azaleas. Thanks!
 
Azaleas and azalea cuttings grow really well down here in my standard bonsai mix - pine bark, sand with some zeolite, dolomite to adjust pH, slow release iron and fertiliser.
At the last property I had little success with Azalea but that turned out to be very acid well water. Ground water here is neutral and everything thrives.
 
Can’t help you. We use the same media Jim Nuccio recommended to us.

We use 60:40 peat: perlite in 2 1/4” plastic grow pots until our whips are 8-18” high.

Takes about 10 months to grow out Osakasuki in our garage in these pots. Properly handled, these
might get more on the 18-24” zone.

Once in 4” to 6” grow pots the media is 50:40:10 peat: perlite:small bark.

Cheers
DSD sends
 
I’m really trying not to buy peat for anything anymore…
You don't really say why - but if it is for sustainability reasons, you can buy sustainably harvested sphagnum moss that is more or less the same thing - you just need to break it down a little.
 
Ye
You don't really say why - but if it is for sustainability reasons, you can buy sustainably harvested sphagnum moss that is more or less the same thing - you just need to break it down a little.
yes for sustainability and environmental reasons. I actually don’t know about the differences between dried sphagnum and sphagnum peat, but do you think it would have the same benefits?
I could do a trial and post the results in this thread.,
I assumed the peat was like incredibly composted, and nutrient dense with a different water holding capacity.. has anyone tried?
 
Peat is composted sphagnum moss. It is acidic and supposedly more nutrient-rich than fresh sphagnum, but I have never used peat for fertilization. Sphagnum on the other hand is neutral pH, and highly water retentive (dry peat is actually hydrophobic). Both have natural anti-fungal properties.
 
Hmm…. Did a deep dive on this topic and posted it a couple years ago. Sustainability issues can be a real morass, which come down to arguments of personal belief, so will keep it as brief as possible.

But let’s short stop this part of the topic for a quick answer to the thought of using ground up long fibre NZ Sphagnum to mimic the properties of peat moss. While sphagnum moss does eventually decompose to peat moss after many years, this process normally requires an anoxic environment and quite a long time to decompose to have the same physical characteristics of peat moss.

On to Peat Moss and Sustainablity

Long and short of it the peat debacle over sustainability of peat harvesting many years ago when the bogs in Europe were harvested, drained and put to use for other purposes. This movement spread slowly across the world, until recently the Patagonia area eventually began to wake up and realize business as usual wasn’t environmentally sustainable.

This reveal caused a number of nations to overhaul their systems and processes towards sustainably harvesting peat. At present the leading countries seem to be Canada, Australia, Finland, Latvia, Estonia and Sweden. At least on paper these countries are recreating bogs as they go, restoring wetlands etc. That said it will take an awful long time to restore a peat bog. However in the case of Canada the amount of bogs under harvest/restoration is very very small.

@Bonsai Nut is correct in directing towards something that is truly sustainably harvested in many places across the world, with more coming, esp. New Zealand who is one of the world leaders in this area. However as stated above, the this product will not be able to directly mimic peat moss.

The problem with the living alternatives is the harvesting, processing and transportation environmental costs.

Harvesting Coco coir a direct product of coconut plantations which are ravaging the environment in tropical areas. The plantations eventually are left an environmental wasteland after depleting the thin tropical soils which is left to erode, often the run off finds its way down onto the coral reefs. imho, from the experience of over fifty years of diving around the world, is doing much more environmental damage than sustainably harvesting peat moss is.

So it’s an issue of competing goods…. Of the not so good alternatives, which… using one’s present knowledge of each products overall environmental costs, is least damaging…

….And this is the crux of all sustainability situations. What item is slightly better environmentally than another item. All have an environmental cost which may be greater than one originally thinks… (include myself in the one please😉)

After years of working with environmental issues in my careers, I’d say… looking at all the possible alternatives for azaleas… small grain Kanuma (smaller than the small grain sold, but the 1;8” screen sifting for these) would be a really good alternative. The Japanese use this media for seedling and cutting grow out. (I believe they also put a layer of sphagnum in too…). The downside is kanuma is bereft of nutrients, so one has to add nutrients… which most often come from a combination of mining and the Haber-Bosch process which uses an extraordinary amount of energy to create agriculturally usable nitrogen.

Consequently we choose to use Canadian peat which is organic and holds moisture well. Then we toss the media into our compost once we are finished.

Cheers
DSD sends
 
For any medium: The carbon footprint will always be higher than if it was left alone. Same for pots, plants and all the other materials.

Sphagnum by itself is acidic - I've tested it. And NZ sphagnum can regrow from dried material. Other species of sphagnum can't do that. I have grown sphagnum for a little over a decade and a 20x50x70 (h x w x l) cm tub will produce enough for my annual demand, powered by rainwater and sunlight, but it does require a peat substrate to get started.
Peat moss and perlite are a good substrate for any plant. But perlite can't really reproduce itself, so I'm not sure if that would solve a sustainability issue.
 
For the rooting in the first weeks itself, mixtures that hold less water are pretty good. So containing sharp sand, perlite, kanuma, etc. If you close off the cuttings to have 100% humidity anyway, you want the soil mixture to be mostly drained of water, but the many air pockets inside the mixture to have 100% humidify. Since there's no roots yes, the cuttings won't draw water from the mixture anyway.

For growing out cuttings into larger plants, I am sure there's peat-free ericaceous potting mixtures available in Portland. I believe those will either have a lot of bark, or coco coir.
I am not fully sure if coco coir is actually good for azaleas. But overall, it seems like it has very nice physical properties. The issues would be that it is not acidic enough, or contains (sea)salt.
Now, you don't actually need a pH 4.5 potting mixture. 6.5 is good as well.
Tap water, time, and possibly fertilizer will raise the pH towards neutral over time, so for that reason having peat or ericaceous potting mixtures could be good, to act as a buffer for the carbonates in your tap water.

As for if coco coir is actually more environmental than peat, that's also up to debate and depends on a lot of factors.
There is a point to be made that Canada's peat bogs are large enough that they can grow more new peat each year that humans can possibly hope to harvest.
But my guess is that most bogs in Canada are not being farmed for peat. And that turning all peat bogs into farms rather than ecosystems is also not good.
In the UK, peat bogs were severely affected and it is literally banned now, I believe.. In the Baltics, it is also a concern.

Theoretically, peat is renewable while things like perlite and kanuma are not. Coco coir requires a lot of fresh water to wash out the salts, which would be rare and precious in the areas where coconuts grow.
And the coco coir needs to be shipped across the planet. It seems composted pine bark may be the best environmental alternative to peat.

It seems we may have enough perlite reserves for thousands of years. So maybe perlite not being renewable isn't really an issue at that level.

I do often get chlorosis on cuttings, and very rarely on seedlings. I believe now that cuttings should be grown grouped into larger trays. And not 1 cutting in an oversized 9cm 3inch pot.
And I see a huge difference between pots with few drainage holes and those with a lot. So you want to use the plastic pot with the most drainage holes.
I used about 200 or so pots that come with just 4 holes and no level difference in the foot. And these are consistently worse.

A higher pot with a lot of drainage holes and peat & perlite would be best for growing out cuttings quick;y. But for growing proper nebari, that would be bad.
You need lower wider pots for nebari. And removing peat from an azalea root ball is very challenging. Kanuma particles can fall off the roots and expose the roots and help you select the roots for nebari.
Lower, wider pots also lack enough gravity and the water table is closer to the roots and base of the tree.
 
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…. NZ Sphagnum moss listed as 4.8-5.0. Thinking the NZ sphagnum used might not as been moisture retentive as peat moss.

On the other hand N.Z. Peat moss is reported at 3.0-4.0. Also reported is that sometimes a batch can be up to 4.5.

Cheers
DSD sends
 
…. NZ Sphagnum moss listed as 4.8-5.0. Thinking the NZ sphagnum used might not as been moisture retentive as peat moss.

On the other hand N.Z. Peat moss is reported at 3.5-4.0

Cheers
DSD sends
 
Excellent conversation. Thank you so much. I’ve bought some fine hemlock bark today. I’ll be testing hemlock/perlite, coir ( rinsed) / perlite with some acidifier ( probably sulfur) , small grain kanuma, NZ sphag with perlite, and if I can find biochar rice husks I’ll try that too ( but it sounds too alkaline right off the bat but I don’t know too much about it. I also have worm farm so vermicast is something I can use to acidify / feed as well. Will likely take a few years and tears but I’ll update any findings in this thread 🙌
 
[...] and if I can find biochar rice husks I’ll try that too ( but it sounds too alkaline right off the bat but I don’t know too much about it. I also have worm farm so vermicast is something I can use to acidify / feed as well. Will likely take a few years and tears but I’ll update any findings in this thread 🙌

Right now, using either a lot of biochar, or replacing your perlite with normal rice husks is definitely bad. But theoretically biochar production can be tuned for acidiphiles. But normal biochar is indeed very basic (pH 8 or 9).
Also, the only decent biochar product that I can find now is almost 10 times the price of perlite per liter. So price-wise it is not an option right now.
I wonder if there is another organic-based, renewable method to produce something just as good as perlite. It just seemed to be that something like rice husks already has the right size. And if you can swell them up and make them more porous through pyrolysis, that would be nice.

Since you live exactly at the nursery capital of the world, and many plants are acidophiles, and most plants are produced in pots, the answer to whatever is ideal right now is exactly in your area. There must be a nursery somewhere that has decided to go peat-free. I would just copy those. And add in either perlite or kanuma the more it moves towards bonsai.

I don't think adding elemental sulphur to potting mixtures is good. Why select a certain potting mix, and then use elemental sulphur to very slowly change it over a period of 1 year? For me, after 1 year, they are ready to be up-potted.
Use elemental sulphur to lower the pH of the full ground. If you grow in a container, you are paying big bucks to be able to specifically select your potting mixture. And you are spending manual labour to repot it. Why do it with something you believe is not good, pH wise, and requires an additional very slow step (elemental sulphur, 1 year of bacteria 'eating it), to resolve? If you ever use elemental sulphur for containers, it should be to keep your pH from increasing over time. That could be a genuine use. I have not heard about such an application. It might be or become a thing if acidophiles are grown in coco coir, though. Not sure. But it is not for peat that's already at pH 4 to 5.


Oh, I tried germinating azaleas seeds and raising seedlings on 100% kanuma. And it was no good. It doesn't completely fail, and I have seen the Japanese use this method in their magazines. But sphagnum and peat just work way way better. It is not even close. But that's for seedlings. Mixing in fine grain kanuma for cuttings up to 100% should be perfectly fine. You just move from a potting soil-based regime to a substrate regime, in terms of watering and fertilizer. Peat and ericaceous potting mix/compost should be easy mode for just growing out azalea plants. And adding perlite is just very good to do. There's even people that claim that 100% perlite is the best growing substrate for pines. Osmocote removes most of my fertilizer concerns. And then I add in some cellulose-rich pine barks so I can believe I am pushing soil microbe balance towards more cellulose-eating fungi, but that is mostly an ease of mind thing.
 
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@Glaucus is correct, any well draining acidic based media will grow azaleas.

The only hitch is which will foster growth of whips to height quickly…. Given proper light, water and nutrients etc

Biochar is used here in small percentages in kanuma and Akadama medias mainly to bump up the CEC,, but there are other benefits too.

Honestly the CEC of Kanuma is pretty darn high, so Biochar provides an additional boost. However for Akadama the CEC is not very high, thus adding Biochar has a much greater effect when using a blended media with Biochar.

Best
DSD sends
 
Right now, using either a lot of biochar, or replacing your perlite with normal rice husks is definitely bad. But theoretically biochar production can be tuned for acidiphiles. But normal biochar is indeed very basic (pH 8 or 9).
Also, the only decent biochar product that I can find now is almost 10 times the price of perlite per liter. So price-wise it is not an option right now.
I wonder if there is another organic-based, renewable method to produce something just as good as perlite. It just seemed to be that something like rice husks already has the right size. And if you can swell them up and make them more porous through pyrolysis, that would be nice.

Since you live exactly at the nursery capital of the world, and many plants are acidophiles, and most plants are produced in pots, the answer to whatever is ideal right now is exactly in your area. There must be a nursery somewhere that has decided to go peat-free. I would just copy those. And add in either perlite or kanuma the more it moves towards bonsai.

I don't think adding elemental sulphur to potting mixtures is good. Why select a certain potting mix, and then use elemental sulphur to very slowly change it over a period of 1 year? For me, after 1 year, they are ready to be up-potted.
Use elemental sulphur to lower the pH of the full ground. If you grow in a container, you are paying big bucks to be able to specifically select your potting mixture. And you are spending manual labour to repot it. Why do it with something you believe is not good, pH wise, and requires an additional very slow step (elemental sulphur, 1 year of bacteria 'eating it), to resolve? If you ever use elemental sulphur for containers, it should be to keep your pH from increasing over time. That could be a genuine use. I have not heard about such an application. It might be or become a thing if acidophiles are grown in coco coir, though. Not sure. But it is not for peat that's already at pH 4 to 5.


Oh, I tried germinating azaleas seeds and raising seedlings on 100% kanuma. And it was no good. It doesn't completely fail, and I have seen the Japanese use this method in their magazines. But sphagnum and peat just work way way better. It is not even close. But that's for seedlings. Mixing in fine grain kanuma for cuttings up to 100% should be perfectly fine. You just move from a potting soil-based regime to a substrate regime, in terms of watering and fertilizer. Peat and ericaceous potting mix/compost should be easy mode for just growing out azalea plants. And adding perlite is just very good to do. There's even people that claim that 100% perlite is the best growing substrate for pines. Osmocote removes most of my fertilizer concerns. And then I add in some cellulose-rich pine barks so I can believe I am pushing soil microbe balance towards more cellulose-eating fungi, but that is mostly an ease of mind thing.
Thanks Glaucus!
I had no idea sulfur took so long to break down to acidify a substrate. I may have to rethink the application..
In Portland, pumice is practically free. We haven’t talked much about that. In the same way that biochar needs to be kind of inoculated with microorganisms and nutrients, I’ve always wondered if pumice could function in the same way… just brainstorming but could you, for instance, soak or inoculate pumice with microorganisms and nutrients ( like vermicast) and sort of charge it like a battery.. with an acidic forward media then use that for the whips? I could be way off..
 
@Glaucus is correct, any well draining acidic based media will grow azaleas.

The only hitch is which will foster growth of whips to height quickly…. Given proper light, water and nutrients etc

Biochar is used here in small percentages in kanuma and Akadama medias mainly to bump up the CEC,, but there are other benefits too.

Honestly the CEC of Kanuma is pretty darn high, so Biochar provides an additional boost. However for Akadama the CEC is not very high, thus adding Biochar has a much greater effect when using a blended media with Biochar.

Best
DSD sends
Thanks deep sea d. I am growing the rooted cuttings in my green house ( hoping they will get long and leggy having diffuse light and no wind ). Do you think CEC is vital for long whip growth?
 
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