Soil Proportions

Watching one of the old Q+As, Ryan answered in a quick and orderly fashion what he uses for soil proportions and I thought I’d list them for everyone.

All of the following are akadama:pumice:lava except for muck which is noted.

Deciduous -
Solid akadama

Pines -
Single flush long needle, dry pine: no 1/16
Leave 1/16 for other pines

Junipers -
Leave 1/16

Spruce, Larch, Hemlock, Fir -
(Water loving species)
Leave 1/16

Muck Creation -
Keto:akadama:long-fibered sphagnum at 1:1:1
(Though absence of keto in later livestreams)

Just a little cheat sheet that I keep in my Notes on my iPhone that I thought others might get use of as we’re getting into repotting season.



Presume that size is screened 1/4 to 1/16th unless noted as “leave 1/16”…which means leave in the entire fraction less than 1/16”?

Everything is 1/4" to 1/16" except for the dry pine species which removes the 1/16" so they would be 1/4" to 1/8".

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Ok…that makes more sense. The short hand was getting me.

Yeah the shorthand is the particle size and up, to the next screen and the screens are at 1/4”, 1/8” and 1/16”.

Or in a maybe less complicated way to describe it, it’s the particle that gets caught by the screen (again with the assumption that your main screens are 1/4”, 1/8” and 1/16”).

And in metric that is (very roughly)

1/4” ≈ 6mm
1/8” ≈ 3mm
1/16” ≈ 1.5mm

The standard nomenclature for sieving materials is to specify both the smallest and largest sieve. In terms of mesh (wires per inch and occasionally wires per cm) the two sizes that Ryan uses are +8/-4 and +16/-4 which indicates the material will not pass through a 8 or 16 wires per inch sieve, but will pass through a 4 wires to inch sieve. This can also be listed in terms of the nominal particle size (what will pass between the wires). It is actually closer to 1 mm that will pass through a 16 mesh screen so the sizes would be +1/-6 and +3/-6 mm. It can be terribly confusing, particularly when you get down into the finer sieves with over 100 wires per inch.

I think everyone cleared up any sort of confusion on the particle sizing, thanks for the input!

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