blueberries and cranberries

Blueberries and cranberries are related to wild fraughan berries, all are bog plants, and like the conditions that heather on the hills like, namely boggy peaty soil, moist but draining and not drying out except for short periods. Cranberries need more moisture than high-bush blueberries.

They must have acidic soil with low pH 4.5 to 5.5. 

If you can supply natural conditions of drained peat bog or moist moorland, that is ideal, but very unlikely.

On acid soils, you can approximate to this by making a trench about 50cm deep and up to one metre wide and line it with polythene perforated for drainage and 5cm of stone at the bottom and backfiled. This will give moist but not waterlogged conditions.

On limy soil, the same trench can be dug out and filled with one part acid soil from Wicklow, Carlow, Wexford and other acid soil areas with blue hydrangeas and three parts lime-free compost or raw peat. Some Miraclegrow needs to be added to the latter at 40g per square metre.

More information at:  https://gardenie.wpengine.com/gerrycategory/blueberries/?id=5482