Sunken acid bed | Raised acid bed
Sunken acid bed
In areas where the soil is limy, an acid soil and peat bed is necessary to grow rhododendron, camellia, azalea, pernettya and other lime-haters. It can be of any size, even small enough for just one plant.
Rhododendrons need acid soil
Raised acid bed
A more simple approach, likely to be more successful, is to simply heap up the acid soil/peat mixture on the existing soil surface to a depth of about 25 centimetres. The sides can be retained by stones, turf sods or timber, or the heap can be graded back to the existing soil level.The acid soil and peat bed actually acidifies the soil beneath over a period of years. A raised bed is ideal for a grouping of lime-haters, but needs to be about two metres in diameter to be effective. Even one vigorous rhododendron would eventually fill an area of this size.Peat beds are prone to drying out because they are raised and they need watering at a rate of at least 70 litres per square metre per month in drought periods. Topping up with peat or well-rotted, organic material such as leaf mould should be carried out every two or three years. An application of sulphate of iron at up to 70 grams per square metre, and 30 grams of Epsom salts, if desired, can be made if the plants show signs of yellowing. Or use seqestered iron, available from garden centres.