Currently I have around 16 middle sized blueberry bushes growing in tubs. I have been thinking of building a couple of raised beds in order to transfer all the blueberries into. The raised beds will be approximately 12 feet long x 2.5 feet wide and 2 feet high. However I am conscious of the fact that it's going to take a lot of ericaceous compost to fill the raised beds and that stuff doesnt come cheap.
Do the raised beds need to be filled with pure ericaceous compost or can it be a mixture of soil and ericaceous compost? Also is there a way to making ericaceous soil or compost myself?