moss grown on the surface

Antrox

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Hi,
can you tell me if the moss that is naturally growing on the surface of my soil is bad or not?
I am usually using potting grit on the surface of my pots because I like it and therefore, I do not have this problem.
But when I do not use topsoil, a thick or sometime very thick moss is growing.
For instance I attached 2 photos
20211208_115027.jpg
20211208_115134.jpg

Is it better to remove it or not? what is useful for?

Thanks
 

Colorado

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Moss is beneficial. Some of us go to great lengths to grow nice healthy moss on the surface of our soils!

The moss stabilizes the surface of the soil and also regulates the water column in the container to prevent the surface from drying out too much faster than the bottom of the container. It has also been discussed that moss can help filter the water to some degree as it enters the container.

Looks like a good moss surface you have going there. I definitely would leave it until you are ready to repot the tree.
 

Antrox

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Thanks Colorado.
I always heard about sphagnum moss for bonsai, hence I was not sure if this type of moss is growing on my pot was good.
That's great so.
I have also noticed that I can scrape the moss and re-place it in a new pot without killing it.
 

rockm

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Alternatively, moss can be a problem.

It is seasonal, it dies off. It is NOT permanent. That die off can produce a layer of dead moss that will act like a roof over your soil, preventing water from penetrating below. Dead moss also dries out and becomes very hard to re-wet...

Additionally, what makes the moss happy may not make your tree happy. Moss is typically happiest when there is a constant supply of water. With bonsai, trees need water, but their roots also need oxygen. Soggy-ish soil that supports moss can kill off tree roots. Moss has no roots, so it has to stay in contact with moisture beneath. That constant moisture can be an issue for the tree.

Also, in Japan, moss is used only temporarily during exhibitions. It isn't really encouraged otherwise. It is grown separately and laid out like a carpet for a given exhibition and removed afterwards.

BTW, what I see in your pot is soil that is compacted and could be having drainage issues, hence the new moss... Sphagnum moss is sometimes used as a loose top layer for recently-repotted trees. Its fibers keep humidity levels high in the top layers of the soil to encourage new roots from recently-pruned roots. It is not kept on the surface for more than a month or so...
 

Colorado

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Alternatively, moss can be a problem.

It is seasonal, it dies off. It is NOT permanent. That die off can produce a layer of dead moss that will act like a roof over your soil, preventing water from penetrating below. Dead moss also dries out and becomes very hard to re-wet...

Additionally, what makes the moss happy may not make your tree happy.

Sphagnum moss is sometimes used as a loose top layer for recently-repotted trees. Its fibers keep humidity levels high in the top layers of the soil to encourage new roots from recently-pruned roots. It is not kept on the surface for more than a month or so...

I don’t agree with any of these points.

All of the bonsai professionals that I am aware of advocate for intentionally growing moss on the surface of the soil. Ryan Neil teaches use of a top dressing comprised of 50% sphagnum moss and 50% collected green moss.

I have never heard of putting sphagnum moss on the soil after a repot, leaving it for a month, and then removing it. Is there a particular source that recommends this?

I also find that the type of moss that occupies the container will be a type of moss that thrives in that condition. The moss that thrives on a Japanese maple might be a different type of moss than the moss thriving on a ponderosa. It is important to collect different types of moss for this reason. Collect mosses from sunny areas, dry areas, shady areas, wet areas. If the soil is staying too wet, then I would say that is a problem with the substrate selection. Not the moss.

Team Moss.
 

rockm

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I don’t agree with any of these points.

All of the bonsai professionals that I am aware of advocate for intentionally growing moss on the surface of the soil. Ryan Neil teaches use of a top dressing comprised of 50% sphagnum moss and 50% collected green moss.

I have never heard of putting sphagnum moss on the soil after a repot, leaving it for a month, and then removing it. Is there a particular source that recommends this?

I also find that the type of moss that occupies the container will be a type of moss that thrives in that condition. The moss that thrives on a Japanese maple might be a different type of moss than the moss thriving on a ponderosa. It is important to collect different types of moss for this reason. Collect mosses from sunny areas, dry areas, shady areas, wet areas. If the soil is staying too wet, then I would say that is a problem with the substrate selection. Not the moss.

Team Moss.
Applying yamagoke/sphagnum moss is common after a repot. Do a search. It comes up on Ryan's feed...I choose to remove the shredded moss after a month or so, or more depending on root development. I don't want moss on my soil. I have found over the years, it greatly complicates watering and can create dead spots underneath. Despite the health benefits that Ryan and company show, there is a significant downside to having moss, particularly thick mats of it on bonsai.

Case in point:

I ran into this issue with my big collected live oak last year. The moss on the soil (which I had allowed to grow in the belief that it was beneficial because Ryan said so...) was shedding water away from roots. That situation eventually killed off significant sections of root mass. Thankfully, the tree needed a repot and the situation was discovered and resolved before it caused significant decline in the tree's health (although top growth was slowing and weakening in some places). The tree spent the last year recuperating at a bonsai nursery. It's been scrubbed of all moss and I don't plan on allowing it again.

I bring this up because the "because Ryan (or whatever expert) says so" is a bad way to do bonsai. sure they know what they're talking about, BUT bonsai is a highly localized thing. What works in the PNW, may not be great other places and for other species.. Moss is not a great idea in my climate from my experience.

Also add to this, beginners just starting to understand their trees are distracted by moss. They tend to want to keep it alive at all costs, including at the expense of the tree's health. Sometimes moss is a symptom of a problem that needs to be understood, instead of encouraging growing moss. This tree looks to have some soil issues that need to be addressed. It looks mucky and needs to be changed. Telling them the moss is beneficial skips past a significant issue that isn't going to get better with more moss.

Team Common Sense
 

Colorado

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I bring this up because the "because Ryan (or whatever expert) says so" is a bad way to do bonsai.

Nice strawman. Never said to grow moss “because [insert professional] said so.” I articulated a number of independent reasons why I believe moss is beneficial horticulturally.

Moss is also superior aesthetically.
 

Wires_Guy_wires

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In my case the moss disperses water evenly and stops soil from hopping out when watering.

Yet I'm as much for it as against it. Sphagnum will always die, because it was either dead to begin with or/and hates the wet/dry cycle. If other mosses don't grow, it's because they don't like the conditions. I found akadama to be more moss friendly than the substrates I use. And the moss does attract birds, which is a constant uphill battle I don't like to be in.
Also arabidopsis is constantly seeding out and plagueing my plants, and moss provides the perfect germination station.

Moss can be a sign of standing water, it can be beneficial and it can be damaging. I do like seeing it, but I dislike what comes with it.
 

Antrox

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BTW, what I see in your pot is soil that is compacted and could be having drainage issues, hence the new moss... Sphagnum moss is sometimes used as a loose top layer for recently-repotted trees. Its fibers keep humidity levels high in the top layers of the soil to encourage new roots from recently-pruned roots. It is not kept on the surface for more than a month or so...

Thanks for the reply.
Are you talking about the starter tree (field maple on first pic) or the bonsai (japanese maple) ? or both?
 

rockm

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Nice strawman. Never said to grow moss “because [insert professional] said so.” I articulated a number of independent reasons why I believe moss is beneficial horticulturally.

Moss is also superior aesthetically.


Not a straw man. You implied that just about everyone agrees with what you're saying. That Ain't true.


for the record:

"All of the bonsai professionals that I am aware of advocate for intentionally growing moss on the surface of the soil. Ryan Neil teaches use of a top dressing comprised of 50% sphagnum moss and 50% collected green moss."

I articulated a number of reasons I don't use the stuff, including nearly losing a substantial 300 year old oak because of this issue.
 

rockm

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Thanks for the reply.
Are you talking about the starter tree (field maple on first pic) or the bonsai (japanese maple) ? or both?
Hi Antrox. I wouldn't actively try to cultivate it on either. That's just me though. Your mileage can vary
 

Antrox

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Hi Antrox. I wouldn't actively try to cultivate it on either. That's just me though. Your mileage can vary
Thanks rockm.
I read the whole discussion above but I do not have the experience on what to do or who's right or wrong : )
In any case, I am going to repot the starter tree next year in spring. The soil does not seem so compacted to me, it drained well but it should have passed more than 2 years from the time I potted there.
Maybe the damp weather and the fertilizer have contributed to that.
So, your suggestion will be to do not save the moss and throw it away. Or maybe removed it and cultivated elsewhere.
It would not be a problem since I am not aiming for an aesthetic result at this time.

cheers
 

rockm

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Thanks rockm.
I read the whole discussion above but I do not have the experience on what to do or who's right or wrong : )
In any case, I am going to repot the starter tree next year in spring. The soil does not seem so compacted to me, it drained well but it should have passed more than 2 years from the time I potted there.
Maybe the damp weather and the fertilizer have contributed to that.
So, your suggestion will be to do not save the moss and throw it away. Or maybe removed it and cultivated elsewhere.
It would not be a problem since I am not aiming for an aesthetic result at this time.

cheers
You can save the moss if you want.
 

Colorado

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Not a straw man. You implied that just about everyone agrees with what you're saying. That Ain't true.


for the record:

"All of the bonsai professionals that I am aware of advocate for intentionally growing moss on the surface of the soil. Ryan Neil teaches use of a top dressing comprised of 50% sphagnum moss and 50% collected green moss."

I articulated a number of reasons I don't use the stuff, including nearly losing a substantial 300 year old oak because of this issue.

Straw man.

My comment was simply a citation to reliable authority. Not blind reliance. Citation to reliable authority increases the credibility of a proposition. It is a technique that you apparently are not familiar with. :)

I think our debate has run its course. The original poster has heard both sides of the Great Moss Debate and can decide what techniques work best in their particular garden.
 

HoneyHornet

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If u remove it make urself a little moss bed.. I prefer to buy the trays that go under your pot but to repurpose them as a planter in themselves and I drill tons of holes in them you can make yourself a nice little Moss arrangement in something like that.

or remove partially so on n so forth.. What is ur soil mix..high drainage or primarily organic..the use of the word topsoil has me curious..the higher draining more inorganic mix can prob tolerate more moss ..in regards to tree health..than a mix tht is mainly organic n wet all the time..i love moss but usually inoculate small areas n let it spread on its own... as for it dying I have experience with my Moss lasting the winter and rejuvenating strong Following season but then certain types of collected Moss have died and become the detrimental lid to the pot as mentioned..def still have some moss that is multiple seasons old tho just sayin..

I also drill mad holes into my pots
 

HoneyHornet

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This is not The most impressive specimen but this Azalea has had this Moss for I think 2 years now it started as a little bit of moss around the base of the tree and spread nice and healthy as you see... what cannot be seen from the image is how much lava rock is involved in this mix and the very many holes drilled into the planting tray.. it drains like a sieve so I believe the most is beneficial in this instance

That's not to say that another blend for another species of tree or another climate and a different Moss will not equate to a different outcome
 

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HoneyHornet

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This is that Azalea currently as you can see it gets these brown little cat tail looking things but round come next season it will be bright green like the picture.. I do go over it and give it a little haircut but it seems to last
 

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