Pumice a substitute for Diatomite?

[matty-j]

As the topic suggests, could Pumice be a substitute for Diatomite?

Cheers
Matt

[g.raft]

Hi Matt,

I will be watching this thread with great interest. Especially watching for those with so much more experience with soil substrates then me and their technical opinions on pumice.

Personally at this stage I love it! Holds moisture beatifully, and the brand I have at present, in my opinion looks better in the pot then diatomite.

I have however been blending it with diatomite as I don't know any better (hence why I'm keen to hear from others)

Pete.

[peterb]

Hi G-raft
I have some trees in pure pumice , trees love it and it holds moisture beautifully but alas it breaks down easier than diatomite is what I've found , you need to treat it gently
regards
peterb

[g.raft]

Hi Peterb,

What sort of time frame are we talking with the breakdown of pumice?

[GavinG]

I have trees in 80% 1-4mm pumice, 20% coco peat, and they thrive. It drains better than 50/50 potting mix and pumice, but seems to hold just as much water - they don't dry out any quicker. I use pumice because I can get 1-4mm grade, where the diatomite is 4-10mm - the smaller grades hold water better due to the larger surface area, but still drain very well. The surface of pumice is crinkly, so it may hold more surface water than smoother diatomite, but I haven't tested for it. I haven't had it break down on me.

Just my 2c.

Gavin

[Scott Roxburgh]

Never had breakdown by itself, but it can be crushed by extra vigorous 'chopsticking'

I have used various grades sifted to different sizes (2-7mm) and my experience with Pumice is that it grows roots better than Diatomite!

In a word, Yes.

[kcpoole]

Thanks Scott and Peter
Re the problems of the latest batch of Mt Sylvia i am intending on getting a batch and trying myself.

Ken

[matty-j]

Thanks for the feedback everyone!

As I am finding it difficult to obtain diatomite at the moment, I think I will reuse what i have and add pumice to the mix until a quality source of diatomite is available.
Also, what about vermiculite?

[kcpoole]

Never seen vermiculilte and never even considered it.

I woud go with your Pumice plan

Ken

[Isitangus]

I use vermiculite added into my mix-primarily for aeration and to lighten the mix.
I get mine from
http://www.australianperlite.com
There's some good info on vermiculite/perlite/pumice in the site as well

[fredman]

Love pumice. Im replanting all my Satsukis in pure pumice. Had one for two seasons as a test and it outgrows the others (mix of pumice/bark/ spaghnum) by a mile...
No breaking down at all.

[peterb]

Hi All
sorry taken so long to reply, what i meant with breakdown was if you are rough with the use of a chopstick when replanting it crumbles alot easier than diatomite , i just find i'm more gentle with it when i mix it with pine bark ( that's the only stuff i add to it ) and repotting . Haven't used it long enough to see how long it takes to break down in the pot
regards
peterb

[kcpoole]

Freeman, have you tried Kanuma for your azaleas?
I will not use anything else myself

[fredman]

Yeah I would like to have it , but unfortunately no Kanuma available in NZ

[kcpoole]

Yeah I would like to have it , but unfortunately no Kanuma available in NZ

now that is a bummer
interesting that you can get Akadama though The products come from the same mines so woudl have thought they are both there.

Ken