Best container soils will have a pretty significant textural component - like bark or turface or granite grit (preferrably all 3). As long as it has this kind of textural quality and drains well, it should be fine.

ps. Most container gardeners avoid MG potting soils like the plague!

Why? What's wrong with M.G.?

The key to successful container gardening is to provide both good aeration and fast drainage. That involves potting mix ingredients that are very textural and durable. MG lacks both of these qualities.....it is of too small and too uniform a particle size (not enough texture) and it tends to be overly moisture retentive (poor drainage).

You want something that includes peat or coir as only a very small portion of the mix, with more durable and textural materials - like fine bark, perlite or pumice or turface/granite grit - as major components of the mix.

You may have to water a bit more frequently with this type of potting soil but the overall health of the plant will be enhanced with improved soil consistency. And I prefer to provide fertilizer when I think it appropriate and of the type that provides a better range of nutrients rather than having the mix provide a less desirable formulation on an ongoing basis.

Well put Gardengal...

I wouldn't use that stuff if you paid me...

MIke

Can I purchase a well mixed potting soil with the above? Or do I have to add the bark/perlite/pumice, etc. ingredients to the mixes I buy? Are these available at the "big box" stores?

Kinda depends on where you are :-) Box stores would not be my first choice of a source......they usually mass market just the inferior stuff like MG but it varies from store to store. .

East of the Rockies, I'd hunt out Fafards Nursery or 51L mix. These are professional grade products but vendors will often bring in as special requests.

On the west coast, look for Kellogg Soil products, carried by better independent retail nurseries. They sell under the names Gardner&Bloome or Master Nursery. Both will have several grades of potting soil - imo, the best tends to be the priciest :-)

You can also customize less desirable potting soils by adding bark fines (about the diameter of a dime in size) sometimes sold as "soil conditioner" or in pet stores as reptile bedding. And add coarse perlite or pumice or turface (may be harder to find). I'd advise at least 1 part each of the bark and perlite/pumiice/turface to no more than 5 parts of the unadulterated potting soil. You can even up that ratio to less of the potting mix if you prefer.