I bought my mother a meyer lemon and potted it in Al’s 5-1-1 container mix. It drained so well that I decided to repot mine as well. One problem you run into with container growing is compaction of the mix and very wet medium. Citrus don’t like wet feet but they need regular watering. The 5-1-1 consists of 5 parts course fir bark (I used Repti-bark), 1 part peat moss, 1 part perlite. Add some lime (dolomitic-which is garden lime and I used the powdered version) and some coarse fertilizer.
The root system, when I pulled out the tree, looked fantastic:
I tried not to damage too many roots, I used the handle of watercolor brushes to tease them out. Then I repeatedly dipped them in water to wash off the soil. This was a seriously messy job. But so far the tree looks great. And it hasn’t dropped the flowers it had. Check out the deep green leaves: