[ContainerTed]

I used to collect all my store-bought potting soil onto a large tarp at the end of the season - one big pile. Then I would throw in some 10-10-10 fertilizer, some composted manure, and a few handfuls of dolomite lime. This would be mixed well and then bundled up for the winter. I also made sure the whole thing was not dried out, but was not overly moist. This was allowed to remain over the winter during which time I would open it up and carefully mix it again. The tarp kept the winter rain and snow from leaching out the nutrients and also kept any weed seeds from germinating and using up the nutrients.

In the spring, I would open it up and start filling up my containers. Using my largest wheelbarrow, I would add in more composted manure and a touch more lime and fertilizer (10-10-10). I would also add in some new potting mix. My goal was to replace about 30-40% of the original growing medium from the previous season. When all the containers were full, the remaining material was added to the flower beds. I would add MG crystals to the watering for the new season's tomatoes and peppers and enjoyed a lot of really healthy plants.

While this method did not get all of the really small, fine dust-sized particles out, it did get a very high percentage of them out. This was very good for ensuring the mix was not "compacting" itself into a "root unfriendly" environment.

Even now, I have a large wheelbarrow and a large screen sifter that I use to do the same thing for the containers I keep up near the house. And, yes, every three or four years I buy a new 30'X15' tarp. They seem to "biodegrade" into an unusable condition in that timeframe.