Garden Q&A: How often should I use bluestone on potatoes?

Whether you're a gardening beginner or expert, Irish Examiner columnist Peter Dowdall has the answer to your questions 

How often should I use bluestone on potatoes for blight?

ANSWER

Bluestone is a form of copper sulphate which is effective at controlling a wide range of fungal problems, including potato blight. 

Mix it at a rate of about 15g per litre and spray it on the foliage of potato plants.

It is often recommended to be used every 7-10 days and I have seen copper sulphate referred to as an “innocuous substance”. 

However, my understanding is that it really should only be used once or at the very most, twice in the year. 

Like most things, too much of a good thing is not healthy!

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