If you are lucky enough, as we are, to have soil that is neutral or only very slightly acidic or alkaline then you can grow just about any plant you want without fancy composts and fertilisers. But, suppose you have alkaline soil and want to grow ericaceous plants then you are going to have to buy in special compost to grow them in.

Different fertilisers are made up with different proportions of nitrogen, phosphorous and potassium to suit the needs of a particular family of plants.

You are asking the question that I asked myself many years ago, Rogi, and the answere is NO!
I now make my own potting composts by mixing soil, grit and leaf mold (humus) together and adding a base fertiliser. You may like to look at my own blog from 29 November 2009 - "Potting Compost Mixes" - for more information on how I do it. Garden soil, on it's own, is not suitable in a pot as it will compact and not allow air and water to percolate.

Thanks Bulbaholic and moon growe for your answers. It was just something that went through my head last night. I think that there is a lot of money to be made from the producers of all these different types of soil and fertililzers making people to believe that without their products their gardens will be a failure. I´m just a "normal" type of gardener that don´t want to have "Super" crops of veggies or prize flowers, so I will try to make my own soils mixed with sand, compost etc, and if they don´t work then I´m not too bothered.....it will be trying by doing.

Bulba. and I don't use fancy composts in the garden becuase, as I've already said, our soil pH is almost neutral and we can therefore grow the plants we want to without problems. If we had alkaline soil we simply wouldn't grow acid loving plants as we wouldn't see the point. Taylor your plants to the soil conditions you have and you don't need any fertiliser at all - simply good humus rich compost.

There is indeed a lot of money to be made from selling gardeners products they don't really need!