Perlite as Pumice in a bonsai mix

[Clicio]

As it is almost impossible to buy pumice in Brazil, my question is:
Can Pumice be switched by Perlite in a bonsai mix?
Regardless of color and lightness of the Perlite, of course.

 

[penumbra]

Perlite tends to rise to the top of the pot. It will work and I have used it but I will probably not use it again for bonsai.

 

[just.wing.it]

Sure....many people use perlite in their mixes.
Worst thing about it is, it floats.....

 

[Clicio]

Perlite tends to rise to the top of the pot.

Worst thing about it is, it floats.....

Thanks for your answer, but that was the meaning of my original question, regardless of lightness.
It floats, sure, but in a mix with other organics like peat I wish to control this "problem", am I wrong?

 

[just.wing.it]

Thanks for your answer, but that was the meaning of my original question, regardless of lightness.
It floats, sure, but in a mix with other organics like peat I wish to control this "problem", am I wrong?

I'd think it would stay put in a mostly organic mix. Just the loose stuff on top may float.

 

[penumbra]

Its cheap and available. Try it. You will definitely have a stark white surface that will be very loose but it may be fine for you.

 

[Sekibonsai]

Thanks for your answer, but that was the meaning of my original question, regardless of lightness.
It floats, sure, but in a mix with other organics like peat I wish to control this "problem", am I wrong?

Yes it will open your soil mix for better drainage should you choose to use organics. It does NOT however have the same soil chemistry/physical properties as pumice.

 

[Clicio]

It does NOT however have the same soil chemistry/physical properties as pumice.

Thanks, in fact this is my mais concern.
I've researched and it seems that even not having the exact same properties, they are close enough.
Example:

Perlite vs. Pumice

Many plants require well-drained soil to thrive. To keep their plants healthy, gardeners...

homeguides.sfgate.com

 

[WNC Bonsai]

Nigel Saunders has switched back and forth between pumice and perlite in his mixes. Last hear he was using pumice but this year it has been perlite. Seems to work well for him. Check out his YouTube channel The Bonsai Zone.

 

[River's Edge]

As it is almost impossible to buy pumice in Brazil, my question is:
Can Pumice be switched by Perlite in a bonsai mix?
Regardless of color and lightness of the Perlite, of course.

They are not that similar in properties as suggested by your quote. Grain size and irregular shape is important in Bonsai Mix. I would be inclined to use coarse sand or granite grit if available to keep organic mix porous. Would also tend to keep the organic percentage low in the 5% range.
However you need to experiment with the best sources you have readily available in your area and match the climatic needs for water retention versus your watering pattern.

 

[Clicio]

Would also tend to keep the organic percentage low in the 5% range.

Thanks Frank, but this percentage of organics doesn't seem to work in Sao Paulo. Summers here are wet but very hot, and lately very long, like 6 months of heat.
Winters are mild but very dry. So organics in the mixes the nurseries around here use are from 20% to 60% of the mix. Which seems to make sense as it will dry fast anyway, be summer or winter...

 

[Wilson]

Perlite works fine for me, just sift and it's good. It is great for developing stock, since it's so much cheaper.

 

[River's Edge]

Thanks Frank, but this percentage of organics doesn't seem to work in Sao Paulo. Summers here are wet but very hot, and lately very long, like 6 months of heat.
Winters are mild but very dry. So organics in the mixes the nurseries around here use are from 20% to 60% of the mix. Which seems to make sense as it will dry fast anyway, be summer or winter...

That makes lots of sense for your situation. That's why i mentioned marketing the right choice in your particular circumstances.
The nurseries around here use high organic mixes as well, This is for cost ( cheaper) and convenience( less labour costs ) watering.
It is true that inorganic mixes require more frequent watering unless adjusted to proportion. A higher percentage of akadama and pumice can make a big difference as well as sphagnum cover!
We are lucky to have a reasonable cost and ready supply of pumice.

 

[Potawatomi13]

Trees will blow over more easily from lightness and do not believe perlite holds H2O as pumice does. Personally would not use.

 

[parhamr]

I believe perlite has a cation exchange capacity (CEC) somewhere near 0% and pumice has a CEC around 10–20%. This measurement is roughly like “how much fertilizer can it hold in reserve.”

Organic soil contents tend to have a CEC around 80–100%, so that’s a useful addition to perlite.

 

[Anthony]

@Clicio ,

perlite smashes as it ages in soil , through root action.

Additionally, we repot in the dry season because the tree masters the
mix and when the rains begin, it is easily able to handle the extra
water.
We also slow the fertilising, once a month or use an osmocote type from
Israel, designed for 30 deg.C and lasts for 6 to 8 months.

Now the BIG SECRET -

Compost holds 2.0 times it's weight in water
Peat Moss holds 1.5 times it's weight in water.

The Internet value which I left here, was to see if anyone cared.

We dried the materials and then did the test.

Someone dropped the decimal point on the Internet and
every site just copied it.

So when we mix 9 parts - 5 mm gravel with 1 part compost for
Ficus p. in a 1 inch deep pot, the tree, eats up the soil so well
that rain has no effect on it.
That tree was the major test factor.
Works on Ficus b as well.

The second test tree was the Tamarind, needs additional moisture.
Thus the use of half the inorganic mix in crushed porous red building block,
with the silica based gravel.

We have already tested 3 mm inorganic / aged compost
in 2.5 cm pots and Tamarinds.
To make the trunks look even larger.
Works.

All plants mentioned are in full sun and we are breezy,

Apologies for the deception.
Just wanted to see if anyone tested information.
Seems to be no - Sad.
Good Day
Anthony

Oh and this range of temperature - over 32 deg.C to a low of 17.8 deg.C
for days ------ can kill Sub-Tropicals.
It seems to be the pot heating up / soil / roots and cooling
to far down.

21 deg.C and above at night seems to have no effect.

Lost old Fukien teas, J.b.p pines, Ixoras, Chinese Southern elm and the Chinese serissas.

However the Sagereetia t, was un affected as it dwells in bright
light under a tall Poui tree.

Seems to have no effect on Ficus b, as the root runs as it wishes out
of the soil.

 

[eryk2kartman]

I used perlite and im happy with it, i agree, its light and can be blown by wind also it floats, but after while you will get some moss growing on it and both problems are gone.......
I used it with all my bonsai soil mix, together with sifted grit its great for drainage, i guess eventually it will break down but so far i was always faster with next repot so in 3 years time i cant see to much difference, and im in Ireland, it rains a lot here.
If you adding organic material to the mix, this will hold your nutrition, i wouldn't worry about perlite has a value near 0%
also very cheap - about 35 quid for 100L bag here, dont buy small 10L bags for 15 you will regret after 2nd bag

 

[WNC Bonsai]

Here is a good link for the properties of various soil mix components (http://www.just4growers.com/stream/growing-media/growing-media-101.aspx). While perlite does have its downsides they may be compensated for with other additives. For example, it does have a very low CEC and is well drained, but you can compensate by adding tree bark compost to the mix. It might take some experimentation to find the best ratios for various plants and climate but that is the fun part, no?

 

[Clicio]

Here is a good link for the properties of various soil mix components (http://www.just4growers.com/stream/growing-media/growing-media-101.aspx).

Excellent, thanks for the link!

 

[SU2]

As it is almost impossible to buy pumice in Brazil, my question is:
Can Pumice be switched by Perlite in a bonsai mix?
Regardless of color and lightness of the Perlite, of course.

Yes you can! I've had little issue with the floating, I mean yes it will tend to 'rise' to the top in the highest inch or two of substrate but this isn't anything that bothers me as I'm developing trees so the aesthetics of my substrate is of zero consequence (I wouldn't advise perlite for showing a tree of course, but for growing it's great stuff!)

I'm unsure how strong the capillary action of pumice is, I know I've found lava rock/scoria at ~3-7mm chunks to be sufficiently 'water-transferring' to use as a majority (even exclusively) component of a mixture, I can't say the same about perlite though - I've had more than 1 occasion where, upon re-/up-potting a specimen that was in a perlite-dominated mixture, I'll find that there's relatively-dry areas of perlite right-beneath my root-ball (on large specimen only, never seen this with some 2" trunked tree), am guessing that while perlite does 'wick' water, it does so insufficiently if&when you've got a rapidly-growing tree sucking the water out of the area, of course some moisture was getting to the center via capillary action but it was minimal and it made for weird root-masses (after the carvings they got they'll be fine / take shape again but I'd never again use or recommend it as anything more than 1/4th maybe, max, of an inorganic mixture that's not being flood-irrigated on a routine basis (I don't mean 1 flooding every day or two, at least here in FL I have the specimen I described where they're getting stunted growth because a good portion of the substrate(perlite) isn't wicking water sufficiently from the sides & down-through to fully soak that large flat area beneath your trunking!)

I do expect that adding a relatively minor % of coconut coir or sphagnum (woudl prefer spagh for its acidity, most irrigation water is alkaline as hell) to the perlite and ensuring it's thoroughly mixed/homogenous-as-possible would go a long way to rectifying it but I didn't care to pursue it, just dropped perlite% and upped organic% (mostly compost & wood-chips, some sphagnum & even less coir. Soon my DIY composts will be ready to use, have been laying composts on-top of inorganic containers and am now finding earthworms in many, many containers upon re-pots [and these containers are on benches lol!!!]