I exclusively use Mel's Mix for my containers. I use them for my potato bins and my tomato containers. Mel's Mix doesn't compact for any reason except stepping on it, hehe. I'm not sure what Al's Mix is but I'm not trying to say it won't work. Just that I had Mel's Mix left over and I'm using it. It works well.

For containers for my tomatoes, I'm using an SWC. Here's link to the blog post for the day I planted my tomatoes...

Here is a link that might be useful: Tomato planting...

Mel says to use his mix in boxes that are raised off the ground, so I think it would work in any container.

However, I'm not sure that I would use it for perennials or shrubs in containers, because the components are not particularly long-lasting. Most SFG is with annual vegetables and flowers, so that you can add compost every year, or more frequently if you do succession plantings.

Of the components of Mel's mix, the compost will decompose further; so will the peat. Al recommends using 5 parts fine bark to 1 part peat because the bark decomposes more slowly and is likely to be good for at least 2 years.

I am trying it. I have tomato plants in 5 gallon buckets with mel's mix. I figured something that could support a plant with just 6 inches of growing medium would be nutrient-rich enough to work in a pot. I just planted them this weekend, but they seem to have survived the monsoon we had in Maryland last night, and drained reasonably well.