[BobE]

True, but it is lime? ericacious means lime hater? Tom just needs a test for lime.

[compostqueen]

Do we really need to be doing a lime test before we water a blueberry with rainwater?  Cor blimey, life is too short 

[BobE]

I was reading about Blueberries which need ericacious  treatment and it advised not to use tap water because of the chemical content.  It set me thinking about water & the organic gardener.  Is it necessary to use only rainwater to be considered "organic" ?

Ericacious is for lime haters.  Tap water may or may not be laden with lime,(mine is, Thames Water), Its not to do with organics.

[Sparkyrog]

Do we really need to be doing a lime test before we water a blueberry with rainwater?  Cor blimey, life is too short 

You should be able to use rainwater NP

[JayG]

The UK standard for tap water is that the pH must lie between 6.5 and 9.5 - in practice the majority of us have slightly alkaline tap water although some of course will lie at the extremes of the permitted range.

Rain water collected directly into a non-reactive container has a nominal pH of 5.6 due to dissolved carbon dioxide, but it can be considerably more acidic than that due to dissolved sulphur and nitrogen oxides, most of which come from the burning of fossil fuels, although thunderstorms also create nitrogen oxides in the atmosphere which add to the background acidity (free nitrogen, but not enough to be able to dispense with the fertilisers!)