I KNOW what JaG is going to say. ;o)

Al

I KNOW what JaG is going to say. ;o)

What? That perlite is a hideous, ghastly, freakish looking white thing that stands out like a sore thumb in a potting mix?

:)

Go for the pumice.

More seriously, perlite is just fine, not every potting mix ingredient can have the same good looks as the sexy Turface and bark. :)

I believe that perlite holds no nutrients at all. Correct me if I am wrong.

I would go for pumice too, if I could get my hands on some locally...:-)

Perlite is virtually free @ $14 for a 5 cubic foot bag. I buy it at a farm supply store. It comes in three grades. I'd stay away from the fine, powdery one as it tends to clump and clog things up.

The nice thing about perlite is it holds moisture. "My" moisture is laden with nutrient and while the perlite itself does not provide anything (except a little phosphorus maybe), it gathers and holds whatever you stick into it.

When I want to switch crops, I merely wash it for three days in 30% hydrogen peroxide and it's good to go; no wee-beasties and the pristine white color comes back too!

Using it as a soil enhancement would give you the same results and while it is true that it floats, that only happens if you over water and leave standing pools.

It's great stuff.

As for pumice, I've never seen it used for anything except for scraping your heels in the shower. It is a lot more dense than perlite. Both are mined from the earth, but pumice is produced naturally by volcanic activity, while perlite is mechanically heated until it explodes like popcorn.

Hope this sheds some light on each.

If given a choice, I opt for pumice as well, simply because it doesn't 'float' to the same extent as perlite.

Sometimes, I'll hold back a small, perlite-free batch of mix to be used as a top-dressing in the container.

Josh

Great help and kind people!

But californian, in the end, it is important for YOU to figure out what "purpose" you are using perlite or pumice for, and why? You can even use both at the same time.

Each has its advantages and disadvantages as was pointed out...

Do you want it to hold nutrients,or to lighten a pot? Pumice is much heavier than perlite..
Do you want to use it for looks? White verses grey?
For the ability to hold its form, or crush over time and disinegrate?
For drainage or for moisture? How much moisture do you want to be held in your soil? Perlite holds alot less moisture than pumice for me.

I question the moisture thing.. If it holds moisture,then why did a soil I accidently made with too much perlite, dry out so fast, on cool days, but even more so, within minutes on warm sunny days? I had to amend it.
How long can a plant survive in a pot with mostly perlite?

I use pumice for moisture, and perlite for drainage.
My pots can go for days without watering, because of the ability for pumice to hold lots of moisture, while at the same time, not keeping the soil "wet" Have you ever heard of "turface". For me it works the same way...
I use perlite for drainage and to keep certain pots light.
In some I use both.

If you can get your hands on both, try growing a plant in 1/2 peat and 1/2 perlite, then 1/2 peat and 1/2 pumice, and you will clearly see what I mean.

Anyway,
I don't know what you are going to use it for.

It is up to you to decide for yourself:-)

Happy growing.....:-)
Thanks everyone for helping out!

It definitely has some good uses, I just wouldn't count on it to hold additional water and nutrients.

Here's some perlite info, mixed with a little about vermiculite, copy/pasted from one of my previous posts:

Perlite is actually a form of porous glass that is made from a mineral called obsidian (or an aluminum silicate rock). It's heated and kind of popped like popcorn. Vermiculite is mica that is treated in much the same way. Trapped moisture expands and creates lots of air pores in both products.

In soils, perlite promotes drainage and improves porosity. It's also effective for starting seeds & cuttings. Actually, perlite holds quite a bit of water @ about 3/4 quart per gallon of perlite. The dry weight of perlite is about 7 lbs/cu ft. Wet, it weighs about 18 lbs for the same volume, so it holds more than 2-1/2 times it's weight in water. Vermiculite is about the same density, and has a even higher capacity for holding water and a very high cation exchange capacity. It also contains magnesium and potassium that are available for plant uptake, but it is not very durable and will compress if handled when wet. It also has a slightly higher pH than perlite.

Al