Hello everyone! I'm relatively new to succulents but the more and more i get into them the more I hear about pumice. So I stopped by a local landscaping place to buy some pumice. I'm used to using perlite so I'm not sure if my eyes are playing tricks on me but this doesn't look like pumice to me, almost more like some type of gravel.

this is it washed



this is it before being rinsed off

I know it as Sponge Rock.

Hmm... Hard to tell from the pictures because both gravel and pumice can have those little black mineral flecks. Pumice is full of air holes, so feels very light compared to regular gravel. Some is light enough to float on water.

How light does your material feel compared to a handful of gravel or pea gravel of the same size?

sumire said:

Hmm... Hard to tell from the pictures because both gravel and pumice can have those little black mineral flecks. Pumice is full of air holes, so feels very light compared to regular gravel. Some is light enough to float on water.

How light does your material feel compared to a handful of gravel or pea gravel of the same size?

I don't have gravel on me currently. But are the air holes visible? Because if so, I'm not seeing any. I guess what threw me off was the color because there's greens greys whites.

does this help at all?

I don't see any air holes either. Does it sink if you drop it in a container of water?

sumire said:I don't see any air holes either. Does it sink if you drop it in a container of water?

nope. All of it sinks

I suspect it is regular gravel.

Speaking as a geologist, that's not pumice. I'm seeing phenocrysts of quartz, feldspar, and biotite. I am not seeing the vesicles (air bubbles) which characterize pumice. It appears to be a crushed granitic rock. Both are chemically similar, but it is the low density and texture (pumice is very fine-grained to crypto-crystalline and vesicular), not composition, which makes pumice unique. Compositionally, perlite is nearly identical to both of these, but its vesicles are man-made by thermal expansion. All are essentially chemically inert.

Here is an image of a few of my orchids. If you tap on the image and blow it up a bit, you will see that material in the pots.


It is available in three sizes, seedling grade, medium grade and coarse. I use it with for bark 50%, 25% sponge rock and 25% charcoal as my mix.
If you squeeze it between your thumb and forefinger, it crumbles easily. If it's 'gravel' it won't crumble. Sponge rock crumbles easily.

Either way, pumice or granite gravel, its usable for mixing with soil for your succulents. I think people prefer pumice because a pot full of gravel and gets pretty heavy.

The supplier refers to it as Perlite-Sponge Rock.

Its not perlite or sponge rock. Its just gravel.

BigBill said:Here is an image of a few of my orchids. If you tap on the image and blow it up a bit, you will see that material in the pots.


It is available in three sizes, seedling grade, medium grade and coarse. I use it with for bark 50%, 25% sponge rock and 25% charcoal as my mix.
If you squeeze it between your thumb and forefinger, it crumbles easily. If it's 'gravel' it won't crumble. Sponge rock crumbles easily.

it doesn't crush whatsoever. I'm leaning on it being some type of gravel.

DaisyI said:Either way, pumice or granite gravel, its usable for mixing with soil for your succulents. I think people prefer pumice because a pot full of gravel and gets pretty heavy.

So it does the same thing as pumice? Any idea what soil ratio I should try out for let's say a Haworthia ?

This is a great conversation. You have 2 geologists, an orchidist and a grower of all things cactus answering your question. At least 3 of us agree about what you've got.

To answer your last question...

First determine if you really should repot. Haworthia aren't usually that big a plant. Find a pot just bigger than the root ball with a drain hole. If you are using regular potting soil, half and half. If you are using cactus and succulent soil, up to 1/4 gravel but, depending upon the brand and for a succulent, you could use it straight. How heavy handed are you with the watering can?

DaisyI said:This is a great conversation. You have 2 geologists, an orchidist and a grower of all things cactus answering your question. At least 3 of us agree about what you've got.

To answer your last question...

First determine if you really should repot. Haworthia aren't usually that big a plant. Find a pot just bigger than the root ball with a drain hole. If you are using regular potting soil, half and half. If you are using cactus and succulent soil, up to 1/4 gravel but, depending upon the brand and for a succulent, you could use it straight. How heavy handed are you with the watering can?

I found a big unlabeled haworthia species at my local nursery and there are a solid 4-5 pups on it. I was wanting to separate some of the pups, and change the mix because it seems very heavy in the organic side of things.

For my succulents i water very sparingly but when i do I tend to give it a nice water until some drips out of the drainage holes.

_sloth_ said:Hello everyone! I'm relatively new to succulents but the more and more i get into them the more I hear about pumice. So I stopped by a local landscaping place to buy some pumice. I'm used to using perlite so I'm not sure if my eyes are playing tricks on me but this doesn't look like pumice to me, almost more like some type of gravel.

this is it washed

It looks like pumice soil.
Just put pumice soil in your browser and then images and have a look.

Its so far down in the pot, I would lift it and add soil underneath. But I never separate plants - I like the huge pile affect. If you do repot, wait until you see active growth.