blue berries

i would probably make sure that you keep the rain water as long as possible to water them with - i had a blueberry bush inside just now - i hadn't got any rain water so i watered it for 3 days with tap water and the leaves curled. it's back to normal now with rain water, but it was a bit scary.

so i watered it for 3 days with tap water and the leaves curled

that was quick the leaves curling I mean, I'm defo gonna collect some rain water.  I did have quite a lot but the sun and sea wind must of evaporated it.  I'll use the bucket with the lid on.  And if the worse comes to the worse leave a bucket outside.

I can't remember where I found it but I have a note about my blue berries that says:-

"Water with rainwater or tap water left overnight with one teaspoon of vinegar in."

No doubt someone can let us know if this is going to help.

A bucket of tap water left outside allows any chlorine to 'disapate' and the water then becomes neutral rather than alkaline.

Chlorine to purify water is (IIRC) hypochlorous acid; chlorinated water is slightly acidic.  Certainly round here, tap water is alkaline because of dissolved minerals (mostly calcium carbonate and calcium hydrogen carbonate).   Neither will react readily with oxygen (in theory you could use atmospheric carbon dioxide to neutralise them, but it would take *ages*), so leaving a bucket overnight will do nothing to help correct alkaline ("hard") tap water.  Some plants are sensitive to the chlorine, though, so stale tap-water is better for them.

Boiling will reduce alkalinity a little, but not enough to make really hard water safe for ericaceous plants.  Distilled water would do, but isn't cost effective!  Bottled water tends to be very hard/alkaline anyway, as it tastes better and most traditional springs are very mineral heavy.  You're left with trying to add acid, either vinegar or commercial iron-based mixes.  Neither is terribly effective long-term, but will do to keep your plants alive in a drought.

I grew blueberry bushes for many years in the states and can say that they need acidic water, and so I second the suggestion of adding a wee bit of vinegar to the water.  They also need acidic soil.  If your leaves are curled and browning on the ends, that's low humidity.    Mist several times a day with regular tap water.  I fed mine with tomato feed in April  and then again once they set fruit.  They can take severe weather quite well if protected.  It was not unusual to have several feet of snow where I lived.  I would pile straw up around them and then wrap them in open burlap bags.  I would have taken the protectional stuff off by now, though, to harden them off some.  Lovely, easy to care for bushes.  Never need pruning, insects seemed to leave them alone.  Birds had a field day though, eating the fruit whole!  Who could blame them?   In the end, I had to put up a net cage around them!  One of mine became spent at 20 years!

I've read elsewhere they are hardy and not really for indoors, and that they last about 20 years.

I'm doomed if we don't get any rain water unless the vinegar method works as our water here is revolting, I can't drink it, think it is very hard.  If you leave it for an hour it tastes even more disgusting like a mouthful of chalk.  I drink bottle water much to my mother in laws disgust but it tastes a hell of a lot better.  I was quite happy to drink it when we lived in thornton heath croydon could leave it all night and tasted the same.  One of my OH aunts used to say the water in bognor regis was the only thing that made her stomach feel better she had stomach cancer s'pose it lined it.

Off the topic ever so slightly, but i made yoghurt and cheese recently and was googling to find out what i could do with whey (excess liquid). 

Seems that blueberries love it.