Potting soil

[Muhammad Arif Khan]

Should the potting soil be changed completely or addition of fertilisers is enough.
If a complete change is required how often should it be undertaken for Annuals and for permanents?

[Izhar]

Addition of fertilizer provides nutrition but the compaction of soil due to watering and gravity along with high density of roots makes the pot environment unfavourable to many plants... we must also consider that some plants need to get root bound to perform better but roots must get oxygen... annuals dont seem to bother.. they just need a good mix to start with and they happily perform with a dilute fertilizer on regular basis... succulents lie adenium does require complete soil change in 2 years.. other perennials and shrubs should get a complete change annually.... having said that we should also consider pot size.. pots less than 20 inch are easy to handle for changing soil... bigger pots for palms etc dont require soil change...

I am in my experiments (read: successful experiments) for growing without soil.. the outcome appears to be so promising that i may replace all the potting soil with other potting mix...

[Muhammad Arif Khan]

Addition of fertilizer provides nutrition but the compaction of soil due to watering and gravity along with high density of roots makes the pot environment unfavourable to many plants... we must also consider that some plants need to get root bound to perform better but roots must get oxygen... annuals dont seem to bother.. they just need a good mix to start with and they happily perform with a dilute fertilizer on regular basis... succulents lie adenium does require complete soil change in 2 years.. other perennials and shrubs should get a complete change annually.... having said that we should also consider pot size.. pots less than 20 inch are easy to handle for changing soil... bigger pots for palms etc dont require soil change...

I am in my experiments (read: successful experiments) for growing without soil.. the outcome appears to be so promising that i may replace all the potting soil with other potting mix...

First part of my question was, Should the potting soil be changed completely that is Old soil thrown away and a totally new soil used.
In case of annuals emptying the pot removes all compaction so just addition of any soil amender and fertilizer should be good enough.
Succulents do not mind bare roots, so change of soil is no problem, but how about other plants like passion flower, Allamanda, Crosendra, Caliandra or the Ixora shown below.
For a retired gardener these questions are becoming important.
For big and real big pots I have a solution in mind, every year take out 4 two inch diameter plugs down to the bottom and fill it with fresh soil, with the obvious advantage of root pruning and the addition of fresh soil .
What has Ifzal to say?