You will probably received as many ideas as people who respond. There isn't a right or wrong answer, just different ways to achieve the same end. The end goal is to have a soil-less mix that is relatively "fast" meaning it doesn't retain too much water or stay wet for days on end, which leads to rot. Some people achieve that by watering less frequently or using less water at at time. Others use various soil mixes.

Many people do not use vermiculite at all, so that is the first option you have. While the most standard AV mix is 1:1:1 (peat, perlite, vermiculite), some people use 1:1 peat to vermiculite. Some use other percentages of the same (usually using more perlite, but not always).

My first thought was that pumice and perlite are more interchangeable than pumice and vermiculite. I'll include a link at the bottom for a discussion here at GW in the Container Garden section where soil-less mix options are frequently discussed; the linked thread discusses the characteristics of pumice and perlite and exchanging them for each other. Vermiculite retains more water than either, as I understand it.

From my perspectice, a lot depends on how you water. If you tend to overwater, or even water other houseplants "just right", then it might be best to leave the vermiculite out and use either pumice or perlite. If using perlite, I'd rinse then screen it (use a strainer or something like that) while wearing a mask to make sure you get the excessive dust and smaller particles out. If using pumice, try to get a size that is uniform and around 1/8" in size if possible.

You could use the AV soil you bought and mix it 1 to 1 with the perlite or pumice, and add some gypsum (it contains magnesium and calcium which many fertilizers do not include and it won't change pH as much as using lime will). You'd have an easy fix, not much to buy, and it would most likely work quite well. If it doesn't work well (either too wet or too dry), then you know what to change next time. If too dry, you find some vermiculite after all or something else that retains water. If too wet, you use less peat and increase the perlite or pumice.

Here is a link that might be useful: GW thread on pumice

So long as you add a good amount of Perlite to the AV soil it will do in a pinch :) Just be careful of the Miracle Grow - they seem to add fertilizer to everything they touch so over fertilizing young plants might be an issue. I think up to 3 months without additional fertilizer has been advised by some.

I find vermiculite at the Blue Seal store (farm animal feed & supplies) or the local Hardware store so you might have luck finding in places not actually a plant/nursery store.

I'm in agreement with just add the extra perlite to any potting soil you buy. Perlite and Vermiculite are seasonal in many garden centers and you will need to wait until spring to find them again. Seems they get one or two orders and once it sells out, they don't reorder until the following spring. I had stopped using vermiculite because I didn't see a need but then I read that the vermiculite absorbs and holds the fertilizer, minerals, elements, so I started using it again. When you find it again, stock up! tish

Oops - just realized I wrote vermiculite in the second paragraph when I meant perlite = 1:1 peat and perlite. My apologies if that was confusing to the kinder_devonshire.

I love perlite. SO helpful in mixes.

Hi KD,
YOu can purcahse vermiculite and perlite from Cape Cod Violetry. John Cook is very good at shipping. You can email John for his caalogue, he will send it to you online or for 2 bucks you could get a paper copy. violets@cape.com
Fred in NJ

Okay, I will try to wait until spring, using liberal amounts of perlite. I was planning on changing my AVs from normal pots to oyama pots next spring anyway. We do have the crematic double pots here for violets, but I kept looking at them and thinking 'they are so expensive' and 'I can't see how they don't drown'. Right now I am working on getting my brother to build me a small plant stand with lights. I can live with what pots I have, but natural light is not going to be enough here in the winter. A couple are already reaching up...
Thank you all for the advice and links.
=^._.^=

kinder,
I am not a fan of those ceramic double pots...the soil stays much too wet because that clay is so pourous. They are beautiful to look at but (IMO&E) not the best thing to grow in.

I do have 2 that are beautiful though...so I put the clear plastic tray down into the inner pot and set the planting pot/cup into that clear tray. I water every few days - that way, I can enjoy the benefit of having the pot with having a better way to grow. Otherwise, about 75% of mine are community wick watered and the rest are individually wick watered.

Dora

Yes, I am staying away from them. Bad for the violets, and if I do a setup like my Grandmother had, you wouldn't see them anyways. She kept a ton of them on a 4' diameter round table. Only saw the pots on the edge. They grew like weeds for her.
=^._.^=

The Oyama pots are wonderful...for me anyway. My plants love them. I have too many to have every plant in one. I also have some ceramic two piece planters and they are very hard to get the mix light enough so the plants don't rot. Lot of perlite and low water level in the bottom part. It is easier to grow in anything else I think! Cape Cod Violetry is very good place to purchase, I recommend them. tish

You could also forgo soil altogether and go hydroculture; you'd never have to worry about drowning your babies again. :-)