Nicky, those 'Drippa' systems are rubbish!! I bought 2 at the beginning of last year and one of them is still packaged The best thing I've found is a 1l water bottle with the bottom cut off, and the lid pierced with a couple of holes, put it lid side down ¼ to ½ way down into the compost at the same time as planting your tomato. Then just fill the bottle daily and leave it to seep down into the compost.

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Sarah

“Tell me one last thing,” said Harry. “Is this real? Or has this been happening inside my head?”
“Of course it is happening inside your head, Harry, but why on earth should that mean that it is not real?”