Top layer of soil smaller particle size?

[Ply]

Does anybody here use, or has anyone heard of using a top layer with smaller particles?

Specifically to use a layer of substrate on the very top layer of the soil (roughly the top 1cm / ~1/2") with a smaller particle size than the rest of the mix (say: top 2mm / ~1/16" versus 6mm / 1/4" for the rest of the soil mix).

Obviously the top layer of the soil dries out the quickest, so this would remedy that to a degree. Allowing for a slightly more even moisture retention across the soil mix, and allowing for more time between waterings. Which can be useful for thirsty trees, especially in summer .

Ofcourse you can use spaghnum moss, which I often do on trees that are quick to dry out the soil. It's functional, but I can't in all honesty say that that looks even remotely good.

Either way, thoughts? Anybody here do this? Would it be beneficial/hurt the tree? I was fairly certain I've seen this come up in something I've seen or read before, but the search function gives me no results.

(Included freedom units for convenience of the reader)

 

[JudyB]

I do this on some of my trees, just know that the smaller particles can move down into the soil over time and change the drainage.

 

[Shibui]

Works Ok provided the small particles will not wash down through the larger soil particles below. Finer soil as a surface layer also helps establish moss if that's the look you want.

 

[jeremy_norbury]

I do this nearly all the time - purely for aesthetics.

 

[Paradox]

I don't believe it's beneficial or harmful to the tree honestly. I can see why people might do it for aesthetics.

I use the same particle size throughout mainly because I don't want to have to dedicate more storage for different sized soil other than what I already use for small trees.

 

[MaciekA]

This is essentially a mild form of top dressing.

I do this nowadays, because all of my teachers do it, and increasingly, my teachers are pushing me to properly top dress everything (i.e. w/ sphagnum) too, not just finer particles. Short of yamadori that still need a lot of root growth, even the pines get top dressed. Better surface roots, better moisture management.

YMMV in NL / farther north / maritime-influenced climate / differing horticultural practices / different containers / different soil, etc, but it works for me.

 

[ShimpakuBonsai]

I use 3 types of soil, very course grain on the bottom of the pot, medium grain on top of that and fine grain as a top dressing.

 

[Deep Sea Diver]

Used to do this, no longer as I’ve found it’s pretty easy to get mountain moss to grow and hold. The moss helps hold in moisture and actually looks really good. Yet if one can’t grow moss….

Also, in the back of my mind there does seem to be the niggling issue of placing smaller particles on top of media, with the constant watering eventually flushing the smaller particles towards the bottom of the pot?

Being of a science bent we tried out using very shallow rooted plants besides moss in the past three years. So far I’ve found two that work extremely well, holding in moisture, markedly enhancing tree growth while allowing good percolation. I’m very sure judges at a show would turn their noses up at these, yet they work.

The first type shown is an extremely small succulent, seems to like moss too.



The second was received from Julian Adams a couple years ago.



Radical departure from tradition, or merely an effective way to help keep bonsai healthy? Something to think about.

cheers
DSD sends

 

[Wires_Guy_wires]

I use fine akadama and other small particle stuff on top and it's working fine.
If bags of fine vulcanic rocks would be smaller than 40L, I would use that on all my soils. But unfortunately I don't have enough plants to finish a bag in one go and they're heavy too.

Moss doesn't like growing in my pots and I'm expanding my rooftop succulent collection to make up for it. Not sure if they would increase moisture content, but they will at least divert some of the heavy water sprays.

 

[cishepard]

Used to do this, no longer as I’ve found it’s pretty easy to get mountain moss to grow and hold. The moss helps hold in moisture and actually looks really good. Yet if one can’t grow moss….

Also, in the back of my mind there does seem to be the niggling issue of placing smaller particles on top of media, with the constant watering eventually flushing the smaller particles towards the bottom of the pot?

Being of a science bent we tried out using very shallow rooted plants besides moss in the past three years. So far I’ve found two that work extremely well, holding in moisture, markedly enhancing tree growth while allowing good percolation. I’m very sure judges at a show would turn their noses up at these, yet they work.

The first type shown is an extremely small succulent, seems to like moss too.

View attachment 496278

The second was received from Julian Adams a couple years ago.

View attachment 496277

Radical departure from tradition, or merely an effective way to help keep bonsai healthy? Something to think about.

cheers
DSD sends

What are the two shallow root plants?

 

[WNC Bonsai]

I have been trying this on a few trees this year after seeing Japanese growers doing it with their mame and shohin trees. But you do have to be observant that your top layer does not develop a crust.

 

[Deep Sea Diver]

What are the two shallow root plants?

Actually I looked and I acquired three. Two came for pots of trees from bonsai that were acquired by me whose owners are deceased.

One, however is from Adams Bonsai - Here’s the description and link.

DWARF SEDUM: Tiny and evergreen, smallest I've ever seen. hardy in cold zone 7. Hugs the ground and spreads happily. $5 each

Hope this helps
DSD sends

 

[yenling83]

I use smaller on the top layer if the tree's in a Bonsai pot.