The first thing I need help with is finding vermiculite in large quantities (4 cubic feet, which is about 30 gallons). I did look online today, because locally the biggest bags available are 2 cubic feet (and I've asked at the various local greenhouses, gardening shops etc.....this is what is available)

If I can find a site that offers the product itself at a reasonable price as well as a decent shipping rate, then it will be cheaper to order it online than it will to acquire it locally.

I realize that there are many threads about where to acquire the vermiculite. However I'm just not sure which type to use because the soil mixture I use recommends it as a fine textured vermiculite, whereas horticultural vermiculite is also supposed to be good to use in soilless mixtures too.

I'm not really sure which type to use, because I used perlite in my soil mixture last year, because that is what I could find. Since vermiculite is available, I'm going to use that.

For my soil mixture, I use a combination of fine pine bark mulch, spaghnum peat moss, vermiculite, lime, and slow release fertilizer (Osmocote).

I never realized there were so many different varieties with the textures of vermiculite. I found out there is very coarse, coarse, medium, fine, and very fine. Depending on what the texture of the vermiculite is, does this affect drainage and aeration of the soil (as in does a finer texture aerate the soil and provide better drainage as opposed to a coarser textured vermiculite, or vise versa)

I found something called Horticultural Vermiculite.

The grade is coarse to medium. However the 'soil' mixture I have recommends using a vermiculite that is finer in texture.

The horticultural vermiculite I'm able to find in bulk at a cheaper price, and the shipping is less expensive. For me it's more economical for to buy the materials for my soil mixture in larger quantities.

Does it really matter what the texture of the vermiculite is with the size? I realize that most people here would prefer to use the variety that has the finer texture, but it's just more practical for me to get the horticultural vermiculite.