Posted: 24/05/2013 at 08:26
That's a very good start. Organic material such as garden compost or mushroom compost help too, but be careful, mushroom compost is alkaline, so ericacious plants won't like it.
You can also add sharp sand and garden lime. If you don't want to make your soil more alkaline then use gypsum instead of lime. Get builder's plaster from your buiklders merchant - that's practically pure gypsum, and a lot cheaper than buying gypsum from your garden centre.